Recent Advances in Aerospace Engineering

Vibration-based health monitoring is considered as an important tool since any anomaly present in the system is manifested through its own vibration signature. This vibration signature is unique in nature. This uniqueness is very well established and being utilized in industry effectively for obtaining vibration response of industrial gear boxes and this forms the basis of diagnosis of the extent to which the gears are working at the intended level of accuracy. In this study, the mathematical model is developed and based on eight degrees of freedom governing differential equations are formed consisting time varying meshing force. Further, this time varying mesh force is diffused in terms of time varying mesh stiffness. The eight degrees of freedom are four rotational and four translational. During mesh in spur gear pair, the load sharing is variable with respect to time along the line of contact and it also depends upon the number of teeth pair in contact. Different faults in gear can be enlisted as crack, spalling, pitting, etc., each contributing adversely on the system characteristics, mesh stiffness being one of those. A cracked gear tooth is attributed by many features such as crack depth, crack length, initiation zone of crack and crack propagation angle. Amidst these, the study associated with the influence of crack propagation angle on gear tooth vibrations has been undertaken and the results are presented in this paper. Time varying mesh stiffness equations are formulated based on potential energy theory and it is solved by using a MATLAB code. TVMS plot is generated to investigate the influence of propagation angle on TVMS.

The advancements in technology have introduced us to concepts like smart cities, smart devices, etc. A city can be considered as smart if it is liveable, inclusive, and sustainable. Other factors like building bold, strategic view for development, inclusive and accessible urban spaces, and services, having trust in government, proper waste management, and pollution management are some of the key factors which contribute significantly to making the city smart. Without oxygen, it is impossible to comprehend how humanity would survive. Modern human culture has had constant growth that has had a negative impact on the quality of the air. Daily transportation and home operations churn up dangerous pollutants in our surroundings. In the modern day, air quality monitoring and forecasting have become cumbersome tasks, particularly in developing nations like India. Managing pollution is becoming the need of the hour. This paper showcases how pollution management can be carried out with the help of machine learning techniques. A random forest algorithm has been applied to the sample data for predicting air pollution. It can be said that if air pollution is predicted at an earlier stage, it can contribute significantly to making the city smart.

After the boom, we all have seen in Educational Technologies during the pandemic times, it has now become a new and more comfortable way for students to educate and up-skill themselves. Even though this has helped a lot during the pandemic times, this way of education is harmful and not appropriate for students in the long run due to various reasons, especially in India. Eduline will provide a platform to connect educators across the globe with students willing to up-skill themselves and solve all the existing problems that are faced by students and teachers with the current platforms. Eduline does not limit itself here, as it will provide more services as the students grow. It is a way of providing fast and high-quality education, counseling, and doubt-solving to students through live sessions and not just some pre-recorded videos. A student’s growth depends on quality teaching and guidance by a teacher; hence, we ensure that they learn from the top educators on our platform.

While travelling in an airplane where one searches for something entertaining to do or watch, despite watching any movie or show or playing a game which does not contribute to an intellect of a child, one can make use of this precious time by playing this game called ‘Net Quest.’ While travelling via air, there is a lot of time for an individual to put his/her mind to work in a good direction and this game provides a perfect experience of educational gaming, not only proving to be fun while playing but also educative while getting to know about important concepts throughout the game. We aim to make a fun 2D platformer game educating about networking concepts using the Unity engine and inspired by AWS Cloud Quest. This game has been designed to easily learn the rules and promote cooperative and competitive learning.

Future space missions are expected to be significantly impacted by developments in hybrid rocket propellant technology. Propellants that are more effective, sustainable, and good for the environment are needed to travel to more places in space and are cost-effective. In the current scenario, it is necessary to use high-performance propellant with the least amount of fuel so that space missions can reach their orbit and accomplished their mission. Sounding rockets, experimental airplanes, and space launch vehicles are just a few of the current uses for hybrid rocket engines. Due to a better combination of fuel/oxidizer and their benefits, such as a high specific impulse, improved safety, and simpler handling compared to conventional liquid or solid fuel rockets, hybrid rockets have the potential to be used in military weapons. The effectiveness of blend metal additions in enhancing the performance of hybrid rocket propellants has been the subject of much investigation. Metal additives can improve mechanical and combustion properties. This paper evaluates fuels such as paraffin and paraffin with additives aluminum and boron and oxidizer as liquid oxygen and discusses their combustion characteristics.

A code smell is a sign or indication that is introduced in the source code of a software program during the design or implementation phases, which may lead to more significant problems during software maintenance. The existing methods have limitations in extracting sufficient rich information from source code, as they frequently reflect various code smells using an easy-to-understand code representation. The objective of this research is examining the code smells with machine learning classifiers. This research suggests the use of metrics extraction software named as WekaNose for the analysis of code smells and training different machine learning models for determining the efficient algorithm. In this research we have used ML algorithms like Random forest, Decision Tree, SVM, Naive Bayes and boosted algorithms such as LightGBM and AdaBoost. The proposed approach performs remarkably well in single code smell identification according to the experimental results obtained.

The manuscript deals with the fabrication of fixed-wing UAV or drone with solar panel on wings. The research work is to increase the endurance of the UAV using the solar power. The research work begins with a suitable methodology to design a solar UAV. Once the design phase is completed, weight estimation was performed with the available design values. The estimated weight was taken as in the input value to predict the aerodynamic forces such as lift and drag. Further thrust was estimated using a test rig and UAV experiments. These performance values are experimental which was obtained using detailed design. Further the airfoil selection and rib design were made, and finally, the structure of wing was fabricated. Similar manner tail was designed and fabricated. All the components of wings and tail were manufactured using laser cutting technology. Finally, the performance of solar cell was discussed, and their performance values are recorded.

The agriculture drone booming up in the drone industry is making a real impact in the society. However, most of the drones used for these applications are imported from foreign countries. The motive of building and testing an agriculture drone in-house makes one feel native. This research work is one with such satisfaction which includes design, building, and testing of agriculture drone with pesticide spraying techniques and equipment. Complete methodology of design and building is explained, and the exact component selection has been decoded. The method of testing motor to obtain the necessary thrust required has been demonstrated. Finally, the successful testing of agriculture drone is done, and the research values are recorded.

This paper presents an overview of control systems for unmanned aerial vehicles (UAVs) and explores their advancements, challenges, applications, and future trends. The introduction provides a basic understanding of control systems in UAVs, followed by a discussion of different types of control systems, including manual control, flight stabilization systems, and autonomous control systems. The paper highlights advancements in control algorithms, such as PID control, model predictive control, and adaptive control and addresses challenges related to obstacle avoidance, path planning, and sensor integration. Applications of control systems in UAVs, such as aerial photography, search and rescue missions, precision agriculture, and infrastructure inspection, are presented. The conclusion emphasizes the need for ongoing research and development to meet the evolving demands of autonomous UAV operations. This paper contributes to the understanding and advancement of control systems in the field of UAV technology.

Tilt rotor unmanned aerial vehicles (TRUAVs) are a novel technology that is gaining popularity in the modern world for a variety of applications, including surveillance, target tracking, search and rescue operations, and civil engineering. The overall dimensions, estimated weight, performance, power needs, and UAV endurance of the aircraft were all computed and assessed based on the conceptual design. An appropriate propulsion system was chosen using these computed parameters. The UAV was given a 3D CAD model. It is designed in a way that it can land on water. The selection of the airfoil for this UAV is one of the most difficult parts which requires many numerical calculations such as trial and error, wing analysis at various angles of attack, and lift estimation and finally configured with NACA6420. In this paper, we discussed the aerodynamic analysis of the UAV under various conditions and obtained the results in reference to various aerodynamic parameters, velocity, and pressure calculations attained. We assessed the obtained results with the ideal conceptual results and reperformed the analysis and optimized the results. The whole data along with graphs are presented in this paper. The contour plots were shown to analyze the pressure distribution among the UAV, and also, the velocity streamlines are also presented to observe the airflow around the UAV. To conclude, this report discusses the potential applications of this particular hybrid UAV and wholesomely presents the conceptual approach, design, and simulation of a tri-ducted tilting rotor UAV.

In this research, the mechanical properties of composite materials were obtained and evaluated. The combination of numerical methods and experimental techniques were used to analyze these properties. Specifically, the mechanical properties at different fiber orientation were observed and discussed. Composite material has been made with the fiber glass and epoxy resin with different orientations (i.e., 0°/45°/90°, 45°/−45°, and 0°/90°). Tensile and bending tests were performed in accordance with ASTM 3039 and ASTM 7264 standards to determine stress, strain, tensile strength, elastic modulus, and bending strength at composite failure. The study found that changes in orientation of fiber have the vital role on the strength of composite material. The fiber oriented at 0°/90° in composite has higher strength (235 MPa) compared to orientation at 0°/45°/90° (226 MPa) and + 45°/−45° (221 MPa) with 2.99% and 1.28%, respectively. The experimental analysis of the composites mechanical properties has been validated with numerical model and ABACUS model. By comparing the values obtained experimentally those from the numerical model, the authors were able to identify areas for improvement and further development in enhancing the strength of composite materials.

Gel propellants, also known as gel fuels or gel-based rocket propellants, are a type of propellant used in certain rocket engines. Unlike traditional liquid or solid propellants, gel propellants have a unique consistency resembling a gelatinous substance. Characteristics of the ethanol gel changes from time to time as the ethanol starts evaporating from the gel propellant when kept in open atmosphere, thus changing the concentration of the ethanol in the gel. Thus, the aging characteristic of the ethanol plays a major role in its atomization and combustion characteristics. An experimental investigation on the aging characteristics of aluminum loaded and unloaded ethanol gel was performed. The atomization of the base gel prepared was also done through impinging jet injector for both the types of gel at varying pressures. The results of aging characteristics obtained for the loaded gel were found to be better than the unloaded ethanol gel. The trends of atomization were observed to be almost similar for both the types of gel.

The paper presents the design, calibration, and navigation of a bird ambulance drone equipped with an APM (ArduPilot Mega) flight controller. The research focuses on developing an innovative and ethical application of drone technology to rescue and assist birds and animals in distress. The study encompasses a comprehensive exploration of the drone’s structural and avionics design, ensuring efficient and swift response during rescue operations. The research further demonstrates the experimental weight estimation and thrust estimation to choose the electronic components wisely. The research work proceeds to the avionic design with configuration of drone which demonstrates the detailed explanation of motions involved in the drone. Then the calibration process involves precise configuration of the APM flight controller, enabling accurate and autonomous navigation through GPS technology. The proposed bird ambulance drone represents a promising solution for wildlife conservation and rescue operations, demonstrating the ethical use of advanced technology for the benefit of all living beings.

In the current study, point-mass trajectory simulation model (PM-TSM) has been developed using MATLAB. Parametric studies of an un-guided rocket at user given parameters and launch conditions were performed as a part of system studies for an un-guided rocket. While conducting parametric studies, a total of 39 cases were studied for GRAD, artillery rocket with varying launch conditions. It is found that GRAD performed better than S-13 T un-guided aerial launched rocket system at 1000 and 2000-m launch altitude with launch angle of 10 and 0 degrees, respectively. The range achieved by GRAD was more than 4000 m, which is considered as the maximum range of S-13 T rockets.

The ongoing demand for lightweight materials is a more promising example of a growth trend in aeronautical and automotive uses. Recently, carbon nanotubes with better mechanical properties are highly desirable for developing some advanced composites. Magnesium has tremendous potential to improve mechanical properties when used in composites due to its wide range of lightweight material properties. Consequently, a magnesium composite was developed by adding carbon nanotubes (CNTs) as reinforcement in a magnesium matrix. A modified form of the friction stir processing (FSP) technology was used to generate the composite to improve CNT dispersion. The perforations in the structure were spaced at 10-mm and 20-mm intervals. Furthermore, the effect of carbon nanotubes was studied and validated using various characterizations. The existence of native phases of the material was confirmed by X-ray fluorescence (XRF) research. The presence of carbon, magnesium, and oxygen elements in the XRF graph indicated that CNTs were implanted during fabrication. Scanning electron microscopy (SEM) was also performed to validate the visual structure of the CNTs, and a consistent distribution was seen across the sample. The hardness test was performed, which indicated that both specimens have more microhardness than the pure Mg. As a result, it has been found that surface composites produced with a higher percentage of CNTs exhibit better microhardness.

The current work proposes a single element of a microstrip patch array antenna that is performing well as a prominent radiation patch element and can be developed for monopulse tracking systems like seeker applications due to its broad bandwidth, effective directional pattern, low-profile conformal design, low cost, and ease of manufacturing. A single unit of a multilayer aperture-coupled microstrip antenna has been developed for the X-band frequency range with a bandwidth of 1 GHz. The single element of a multilayer antenna structure is designed to obtain a low return loss, wider bandwidth, better directivity, and better gain. For a multilayer microstrip antenna that operates at the center frequency of 10.9 GHz, the return loss of − 42 dB with 6.3 dBi gain, having VSWR < 1.5, has been achieved by analyzing using the CST Microwave Studio EM Simulator.

In the present study, various samples of jet fuel blended with 2-propanol have been prepared in different ratios. All the samples were used for the determination of heat of combustion (∆Hc, MJ/kg), and only one blending sample was chosen for determining the surface tension (σ, N/m), viscosity (µ, mmPa.s) and density (kg/m3) values using different analytical instruments. We measured surface tension, viscosity and density and did comparison with pure jet fuel properties. Heat of combustion was measured using bomb calorimeter, surface tension was measured using stalagmometer, viscosity was measured using rotational viscometer, and density was measured using digital electronic weighing balance. All the obtained data are discussed in the form of table and graphs in the article. From the obtained results, it was observed that binary blending of jet fuel and 10% (by weight) 2-propanol is better in terms of heat of combustion values and may be utilized as alternative fuel. Some catalysts were also added in the fuels samples, but the results were not very encouraging. However, these catalysts can be used in nano-form or in gelled fuels for better results.

This paper presents a control strategy for a quadcopter carrying a slung load. The Euler–Newton method is used for obtaining the complete non-linear model of the 6-DOF quadcopter system and a slung-load system capable of performing the swing motion along two directions. Both the system dynamics are coupled by adding the swing forces to the body forces of the quadcopter. This coupling leads to the undamped swing motion of the slung load which may cause unstable oscillations for the quadcopter, thereby degrading its performance. It is important to damp this undesired swing motion of the slung load. The objective of the controller is to allow the quadcopter to transport a slung load to the desired position without affecting flight stability. A combination of proportional-integral-derivative (PID) and non-linear PID (NLPID) controllers is used for the target position tracking control. A separate PID controller is used for damping the slung load’s oscillations.

This study focuses on optimizing propeller design for small unmanned aerial vehicles (UAVs) to enhance their mission-specific performance. As UAVs gain prominence, there is a growing demand for improved propulsion and energy management systems. Many vertical take-off and landing (VTOL) UAVs rely on fixed-pitch propellers, leading to compromises in mission execution. To address this, the study suggests adopting variable-pitch propellers with aerofoils featuring leading edge flippers to influence aerodynamic behavior and prevent stalls. These flippers are strategically positioned at the propeller’s tip and hub to enhance efficiency. Two propeller pitch configurations, 4 × 7 and 4 × 9, were examined, each with variations including no flippers, four flippers at the hub and tip, and eight flippers at the hub and tip. Through comprehensive testing, the study aimed to evaluate each design’s performance in terms of propeller efficiency, thrust, and torque under specific conditions. The results indicated a significant increase in efficiency, ranging from 60 to 70%, depending on the pitch. This comparative analysis helps assess each pitch’s suitability and effectiveness for UAV applications.

The finite element method (FEM) is a popular numerical technique for solving partial differential equations (PDEs) arising in computational modeling. Several engineering problems, such as those involving fluid flows, electromagnetics, heat transfer, and structural analysis, have been effectively solved using FEM. It is the most powerful tool currently in structural analysis. Recently, machine learning (ML) approaches have been used to enhance the performance of FEM. The main aim of this study is to build an artificial neural network (ANN) model using deep learning, a popular and powerful ML algorithm that can estimate the elemental stiffness matrices of 3D 8-noded hexahedral elements with very high accuracy. The performance of the model is evaluated by comparing it with Cook’s beam problem. The model predicts the displacement of the beam with an error of 0.74%.

This paper investigates the control strategies for a quadcopter UAV controlled by a Pixhawk-based flight controller. First, the nonlinear mathematical model of a quadcopter has been derived considering its aerodynamic and rotor effects. From this model, it can be seen that the quadcopter is a nonlinear underactuated system which makes its control design challenging. Two control approaches for this quadcopter system have been chosen and analysed here, the linear proportional–integral–derivative (PID) control and the nonlinear Backstepping control approach. Both approaches were adapted for use in the PX4-Pixhawk-based controllers. Their performance was tested with a quadcopter dynamic model and the results were simulated. A comparison of the obtained results indicates that the Backstepping control technique settles > 5 times faster than the PID control and also provides more stability to the system making it the preferable control strategy for quadcopters using Pixhawk-based autopilots.

UAVs are transforming the global market as a compact, cost-effective product for various applications. These unmanned vehicles are easily accessible and gather valuable data from any desired location. However, the unauthorized use of these UAVs damages people and places’ safety, security, and privacy. Demand for new technologies to counter UAVs is crucial. Counter UAS (CUAS) have evolved to nullify the threats caused by these vehicles. While most CUAS use radar to detect and jam the drone’s signal, limiting the system’s operation to a particular area. The purpose of our project is to study and implement a mechanism that allows flying UAVs to be tapped using a net. An effort was made to develop a compact and robust mechanism to launch a net at the enemy drone to destroy it. Testing was done with different mechanisms and finally settled on a compressed air mechanism that propels four deadweights connected to each corner of the net using a solenoid valve.

The present study aimed to compare the effect of swirl injection on the regression rate and combustion efficiency of a hybrid rocket using two different lengths to diameter (L/D) ratios for the motor: 9.5 and 17. The fuel used was HTPB, and the oxidizer used was GOX. The significance of using a swirl injector is that it introduces an additional tangential velocity component, in addition to the axial component of conventional showerhead injectors, in the hybrid rocket motor. For the larger motor of 340 mm, it was observed that the improvement in regression rate was achieved only up to a length of 210 mm. This implies that the head end swirl injector was not capable of providing a swirling flow all the way to the nozzle end. When comparing the regression rates of the showerhead and swirl injectors for the 190 and 340 mm motors, an increase was observed in the case of swirl injection. Study revealed that in terms of combustion efficiency, the showerhead injector and the swirl injector exhibited contrasting results for the 190 mm motor. Specifically, the swirl injector demonstrated an 11% increase in combustion efficiency compared to the showerhead injector. However, for the 340 mm motor, the increment in combustion efficiency was comparatively lower at 6%.

A chemical rocket propulsion system that employs fuel and oxidizer in different physical states is known as hybrid rocket motor (HRM). HRM has some issues like low regression rate and less efficient combustion. Apart from these issues, the system has some special superiority like safest and cheaper system in comparison with other chemical propulsion system which makes it preferable for space tourism. So, diminishing this system’s concern can give extra boost in the research field of this propulsion setup. The offset grains can be a revolutionary step in the HRM. They can create recirculation zones due to change in alignment, and using multiport grain with it can also enhance the regression rate due to extra surface area exposure. The result showed that the regression rate obtained with offset grains having multiport was 2–3 times higher than the normal port grains. The combustion efficiency was also 20–30% higher than the normal port grain.

Pyrotechnic igniters are used to ignite the small solid propellant motor. The combustion of the pyrotechnic igniter plays an important role in building the pressure inside the combustion chamber of the solid rocket motor. The igniter should be able to generate pressure in the combustion chamber in a fraction of the time and should be efficient. This research paper examines the effectiveness of two metal fuels, magnesium and aluminum, in combination with potassium nitrate as an oxidizer for pyrotechnic igniters used in small solid propellant motors. The fuel-to-oxidizer ratio is maintained at 50:50. The study reveals that the Mg/KNO3 igniter mixture outperforms the Al/KNO3 mixture in calorific value, with a 7406.32 kJ/kg value. However, it is to be noted that the incomplete combustion of the Al/KNO3 mixture leads to a higher gas generation compared to the Mg/KNO3 mixture. These findings underscore the significance of selecting the appropriate metal fuel for pyrotechnic igniters to optimize performance, considering factors such as calorific value and combustion completeness. The outcomes of this research contribute to developing and improving solid rocket motor efficiency.

This research shall focus on the intensification of pre-existing manual drones equipping them with a variety of sensors making them autonomous, and capable, and proposing them for a variety of roles including thermal sensing, data collection, tracking creatures, forest fires, volcano detection, hydrothermal studies, urban heat, island measurement, and other environmental research. The system can function for reconnaissance, research, 3D mapping, and search and rescue missions. This study mainly focuses on automating tedious tasks and reducing human errors as much as possible by reducing deployment time and increasing the overall efficiency, efficacy, and reliability of the UAVs. Creation of a comprehensive Ground Control System UI (GCS) enabling less trained professionals to use the UAV with maximum potency. With the inclusion of such an autonomous system, artificially intelligent paths and environmental gusts can be avoided. The research paper aims to tackle and implement the above-mentioned goals.

Fixed tricycle landing gear for 3-ton Unmanned Aerial Vehicle (UAV) with a Main Landing Gear (MLG) as a spring-leaf structure is designed. The design process is divided into specific phases: design requirements, preliminary design, detailed design, and testing. Ground load conditions are calculated in the initial design phase. The modeling begins by adding different geometries of clamping the primary strut with mild steel as the material. It is observed that the design is notwithstanding the load obtained from the ground calculations. The design is modified with clamps and connecting rods to meet the expected maximum stress during landing conditions, reducing the working stresses on the strut considerably. The stress profiles obtained from the study show that for all the models, the Mises stress observed is within the allowable stress limit. In contrast, the displacement observed is not in the allowable range, which may lead to structural damage due to a lack of shock absorption during landing.

Vibration in a mechanical structure is of great importance as it can cause extensive damage to the structure’s property if not dealt with properly, especially in the domain of aircraft and aerospace engineering. If the natural frequency of an aerospace structure becomes equal to the externally supplied vibration frequency, the structure starts resonating, which can lead to the shaking of the flying vehicle and thus the ability to change its flying path or lead to its deformation. Therefore, the vibrational and structural analysis of an aircraft wing is one of the most important components during the aircraft design process. This paper’s study reports the formation and comparison of a realistic wing model of Lockheed C-140 aircraft wing that has Lockheed C-141 BL0 airfoil at its root and Lockheed C-141 BL761.11 airfoil at the tip, which is created on Autodesk Fusion 360, to that of a cantilever beam to determine its natural frequency, both by using simulation by ANSYS Workbench as well as conducting experimental testing by calculating the mode morphologies through experimentation of a scaled (1:61) 3D printed model of the wing and the beam in consideration. This study talks about vibration reduction methods to stabilize the wing using dampers or composites to structurally enhance it.

Dynamic stall is an inevitable complex flow phenomenon in rotorcrafts, wind turbines, supermaneuverable aircrafts and flapping- wings. Although experimental studies on dynamic stall pose difficulties, a great interest lies in understanding and mitigating its effects. Researchers opted for computational techniques and empirical/semi-empirical models for predicting the aerodynamic loads under dynamic stall conditions. The current study aims to understand the dynamic stall of an airfoil exhibiting pitching motion through numerical simulations and ONERA’s semi-empirical model. The numerical simulations are carried out for different reduced frequencies of range κ = 0.03, 0.05, 0.1 and Reynolds numbers Re =  $$3\, \times \,10^{4}$$ 3 × 10 4 , $$3\, \times \,10^{5}$$ 3 × 10 5 , $$3\, \times \,10^{6}$$ 3 × 10 6 . An open-source computational fluid dynamics software, OpenFOAM is used for the simulations, and the results are compared with experimental data and the ONERA model. The features of dynamic stall are examined effectively, and the results correlate well against the experimental data. With the decrease in Reynolds number, an increase in lift-curve slope is observed during the onset of dynamic stall.

In this study, we model an unsteady conjugate heat transfer problem of a solid square cylinder confined in a straight channel with adiabatic walls. In modeling of the problem, we use an in-house developed Lattice Boltzmann solver that can run on GPU. To validate the solver, we compare the obtained results with the data from two previous studies that are available in the literature by considering pressure distribution on the cylinder and spatially averaged Nusselt number along the cylinder edges. The results are in good agreement in general and promising for future studies to reveal unsteady and complex nature of the problem.

Gimbal bellows are used in the feed systems of the cryogenic stage of an indigenously developed launch vehicle for minimizing the actuator loads as well as convey the propellants to the cryogenic engine, whilst it is gimballed. Gimbal bellow is a universal joint in which two rotational degrees of freedom with specified stiffness are provided. As a part of design qualification of the bellow duct, structural capability of gimbal bellow with respect to pressure is required to be demonstrated through a burst test. Non-linear elastoplastic stress analysis is carried out for the estimation of burst pressure of the gimbal bellow. Burst pressure is estimated based on the pressure at which deformation shows an asymptotically increasing behaviour and the analysis un-converges. The instrumentation is designed for the measurement of displacements and strains at critical locations, and burst pressure test is conducted. The predicted burst pressure of gimbal bellow through simulation is 7.46 MPa compared to the tested burst pressure of 7.89 MPa. The burst pressure and the strain/displacement values matched very well with analysis predictions. The location of failure also matched favourably.

The paper presents an extensive review of the application of machine learning (ML) techniques, especially artificial neural networks (ANNs), in the realm of crashworthiness, hypervelocity impacts, and inverse analysis across various structural and aerospace domains. It delves into the prediction of stiffness matrices, contact stiffness, impact forces, and failure conditions, showcasing the potential of ML to streamline complex structural analysis processes. While the review highlights the predictive accuracies and computational efficiencies achieved by these methods, it also underscores the need for a more critical evaluation of model robustness, uncertainties, and real-world applicability. The review offers valuable insights into how ML can transform inverse analysis yet emphasizes the importance of addressing challenges and limitations to ensure the reliability and practicality of these innovative approaches.

Thrust vectoring is the technique by which the jet coming out of the nozzle is made to deflect to control the vehicle. Fluidic thrust vector control by dual throat nozzle is found to have the highest thrust efficiency with minimum pressure losses. The present study involves the design and simulation of a dual throat nozzle (DTN), a DTN with injection (I-DTN), and a bypass dual throat nozzle with a V-shaped bypass duct (V-BDTN) and with an arc-shaped bypass duct (A-BDTN). The arc-shaped bypass duct design idea is taken from the author Wu and Kim (J Mech Sci Technol 35:3435–3443, 2021). It is found that I-DTN has the highest deflection angle of 12° for NPR = 4 and the highest coefficient of the thrust of 0.96. But implementing DTN with injection has the starting problem as mentioned in the research literature. To overcome this, A-BDTN and V-BDTN are introduced. Also, A-BDTN’s coefficient of thrust is very close to that of a DTN which means the thrust penalty for vectored state is negligible.

Ground infrastructure for space launch systems is designed against thermal, over pressure, acoustic and vibration loads. This paper focuses on studying the properties of aluminum–polyurethane foam (AL-PUF) sandwich composite using experiments and computational methods for precise prediction of behavior of material for space-based applications. AL-PUF panels were subjected to quarter point loaded four-point bending test to obtain the deflection for a range of loads in order to study the mechanical properties of the material. A theoretical model of four-point bending test, its associated loads and deflections are also described in this study. A computational model (FEM) of AL-PUF specimen under four-point bending test was developed to find deflection of material under a range of loads and subsequently obtain modulus of elasticity of the material. The modulus of elasticity calculated using experimental (0.53 GPa), theoretical (0.551 GPa) and numerical data (0.553 GPa) was found to be in agreement. The core shear stress and facing bending stress were obtained to be 0.20 and 14.89 MPa respectively. Further, specimens of the material were mounted to downstream of nozzle exit of a launch vehicle stage and subjected to different heat fluxes to study the behavior of material under thermal loads. A transient thermal model of the material specimen under radiative heat fluxes was developed to numerically (CFD) predict the results of experiments, and it was found that epoxy adhesive undergoes phase change including melting, burning and material degradation. The experimental data were in agreement with the results obtained numerically using CFD.

Composites are suitable materials to fulfil the multifunctional applications for the requirements of modern industry. The composites are fabricated by combining two or more materials whilst taking benefit of their individual properties. The composites fabricated with aluminium as matrix materials are known as aluminium metal matrix composites (AMC). The physical and mechanical qualities provided by AMCs for future material applications are remarkable. As per research findings, the inclusion of reinforcements into the metal-based matrices enhances the characteristics such as strength, stiffness, wear, fatigue and creep. Generally, ceramic particles are used as inclusions to enhance the above said properties of AMCs. Addition of Li to aluminium causes a drop in density and an increase in the elastic modulus along with significant improvement in strength. Al–Li alloys attract researchers because of their excellent wettability and the ability to be hardened by precipitation hardening. When ceramic particles are included in Al–Li alloys as reinforcements, the performance limitations of the alloys present a substantial improvement. The present article attempts to give an overview of the impacts of various types of reinforcements in Al–Li alloys. The review’s primary focus is to reveal the effects of different ceramic reinforcements such as SiC, B4C, TiB2 and Si3N4 on the mechanical and metallurgical characteristics of AMCs of Al–Li alloys.

Glycidyl azide polymer (GAP) is explored as an energetic binder/plasticizer for propellant due to its superior performance compared to hydroxy terminated polybutadiene (HTPB). GAP polymer contains an azide group which is very unstable, and at lower temperatures, the azide group tends to break making it an energetic binder/plasticizer. It can be mixed with low energetic and clean oxidizers such as AN, KN to improve the specific impulse and high energetic oxidizers such as ADN to reduce chlorine emissions for greener propulsion. The present study aimed to synthesize GAP as a plasticizer and increase the yield with an increase in temperature. The present work indicates that the increase in temperature of the aziadation process helps in increasing the yield of the GAP.

The curing process plays a crucial role in solidifying composite propellants, which consist of hydroxyl-terminated polybutadiene (HTPB) as a binder and ammonium perchlorate (AP) as an oxidizer. This paper examines and discusses the impact of curing time and temperature on solid propellant samples, considering factors such as burn rate, mechanical properties, FTIR characterization, and thermal decomposition analysis. Through experimental methods, it was observed that all the aspects were positively influenced. Specifically, increasing the curing temperature led to an enhanced propellant burn rate. Similarly, the mechanical properties such as Young’s modulus, hardness, and elongation at break for the sample with 60 and 70 °C curing temperature lie in the standard range, whereas the rest of the samples are beyond the range due to a higher curing temperature which makes the sample brittle. FTIR analysis revealed changes in the strength of the isocyanate functional group, indicating the formation of allophanate linkage at a curing temperature of 100 °C. Moreover, the thermal decomposition of samples with 60, 70, 80, and 90 °C curing temperatures indicated three major peaks, but in the sample with 100 °C curing temperature, one more peak was detected at around 370 °C shows that the decomposition process of oxidizer and binder has divided into two different peaks. Considering the overall perspective, it was evident that an increase in curing temperature significantly affected the propellant and its burn rate, mechanical properties, FTIR analysis, and thermal decomposition.

This research paper focuses on the application of Model Predictive Control (MPC) on a 3-degree-of-freedom (DOF) Marine Robot (USV). Marine Robots are multivariable, nonlinear, and coupled systems. Controlling these vehicle trajectories is a challenging task for the researchers. The MPC control algorithm is designed such that USV can track a desired reference point. The efficiency of the MPC control algorithm on the USV is examined in the MATLAB environment. Using the MPC control method, results demonstrate that the USV can successfully track the desired reference point.

Reentry from orbit is a critical phase in the entry trajectory. For a non-propulsive ballistic entry, static and dynamic stability plays an important role in the trajectory, especially for the safe deployment of parachutes, typically at high subsonic Mach numbers. Static stability of flight vehicles is being estimated through empirical methods, CFD and experiments. Longitudinal static and dynamic stability of a typical reentry body for subsonic Mach number of 0.6 is predicted using commercial software CFD +  + and presented here. Steady state simulations are carried out for low angle of attack at α = 0 and 2° on an unstructured grid using SST k-ω model. Transient simulation using forced oscillation method is used to compute pitch damping derivatives. Results for transient simulations are validated against test data.

Unmanned aerial vehicles (UAVs) have become immensely popular in various applications, from surveillance, monitoring to package delivery, search, and rescue missions. Efficient path planning is a crucial aspect of UAV operations to ensure safe and optimal navigation in complex environments. Given its efficient detection of ideal paths, the A* algorithm has drawn considerable interest in the world of path planning. This paper presents an extensive investigation of the A* algorithm and its application in UAV path planning. The objective of this investigation is to analyze the performance of A* in terms of path optimality and versatility across various test cases. The paper provides a comprehensive overview of the algorithm, including its underlying principles and heuristic search strategy. Through the means of this, we have tested the proposed algorithms on various test cases and obtained collision-free traversal.

Related to high-performance flapping micro-air vehicles (MAVs) or unmanned air vehicles (UAVs) has a significant impact on flight performance and mission capabilities, so the development of lightweight, compact, and energy-efficient flapping mechanisms is important. The substantial design validation and performance assessment are very much required for the realization of such a flexible as well as intricate flapping mechanism with the extra capability of producing thrust levels that bound to cruising forward flight and vertical take-off and landing (VTOL) situations. The development of a robotic bird still faces substantial challenges in simulating a bird's periodic main wing action to produce lift and propulsion. The processes like flapping, folding, bending, and twisting make up the major wing action sequences. Bird flight served as the model for the artificial bird's initial design, which was based on decomposing that intricate motion into a simple mechanism. The design made explicit use of the Festo Corporation's existing and distinctive “Smart Bird” flapping-wing unmanned aerial vehicle (UAV). In this paper, I and my colleagues design a version of flapping-wing UAV or an ornithopter and then fabricate it into a fully functional flying mechanical bird.

Intermetallic-based alloys due to their unique material properties are considered as most suitable modern engineering materials. The present study depicts the elastic, mechanical, and thermophysical properties of aluminides at nanoscale using ultrasonics non-destructive evaluation (NDE) technique. Ultrasonic method is one of the popular methods used widely to characterize the microstructural properties at bulk as well as nanoscale. To evaluate ultrasonic and thermophysical properties, the second-order elastic constants (SOECs) obtained via application of using the Coulomb–Born–Mayer interaction potential for the chosen material. The mechanical parameters have also been evaluated based on obtained SOECs. It is found that Young’s modulus for nanostructured aluminides matches with the reported range of 180–281 GPa. The better ductile behavior of nanostructured NiAl in comparison with nanostructured FeAl is confirmed by Pugh ratio. The ultrasonic velocity has been further utilized to find out the lattice thermal conductivity. All the computed parameters have been utilized to find out the thermal relaxation time, Debye temperature, and acoustic coupling constants for nanostructured aluminides. The ultrasonic theoretical model with well-established relations has been utilized to characterize the nanostructured aluminides. MATLAB as a simulation tool has been utilized to obtain the material characteristics.

The aim of the paper is to design the aerospike nozzle and analyse the flow over it for various conditions by carrying out flow simulations in software. Contour was obtained with the help of a MATLAB Code. Effect of different atmospheric pressure, varying with altitude, in correspondence with the design pressure has been studied through numerical simulations in order to understand the performance of the aerospike nozzle in conditions categorized as over-expansion, optimum and under expansion (Nazarinia et al., Design and numerical analysis of aerospike nozzles with different plug shapes to compare their performance with a conventional nozzle [1]).Also, how the changes in various parameters impacts the performance is studied. Thrust is a very important parameter in gauging the functionality and capability of the aerospike nozzle. The overall thrust generated is calculated with the help of the MATLAB code generated for 100% length spike. Overall thrust is a combination of the thrust that is generated due to that of the chamber force and the one due to the flow of the gases over the spike (Besnard et al., Design, manufacturing and test of a plug nozzle rocket engine [2]). The program build helps in quickly obtaining the thrust values for different conditions imposed. The outcomes of the analysis depict how the aerospike showcases good performance even during its operation at altitudes other than the optimum altitude.

The combination of robotics and aerodynamics has proven to be an interesting field of study, leading to advances in many fields. This brief presents a new approach to the design and control of a robotic arm that focuses on aerodynamics. The robotic arm uses an Arduino microcontroller for simplicity and ease of use. The aerodynamic design of the robot arm is designed to increase efficiency and effectiveness by reducing weight and improving lift. By using the aerodynamic structure, the structure of the arm is streamlined to reduce air resistance, resulting in more fluid and clear power. The choice of heavy and durable materials further contributes to the aerodynamic performance. The control of the robotic arm is used by the Arduino microcontroller, which provides various platforms to work and interact with various sensors and actuators. Control algorithms include real-time feedback from position and force sensors to make precise and responsive movements. Aerodynamic design principles are incorporated into the controller, which can adjust the configuration of the robotic arm according to atmospheric conditions. This research contributes to the field of robotics by demonstrating the benefits of integrated aerodynamics and Arduino-based control in the creation of human arms. These findings lead to the development of more efficient robotic systems and provide valuable insights for future research at the intersection of robotics and aerodynamics.

The demand of aircraft maintenance engineers (AMEs) is significantly increasing year by year as the growth of aviation industry is rapidly growing worldwide. The regulatory bodies have to ensure adequate training is provided to the prospective AMEs and licensed timely. The International Civil Aviation Organization (ICAO) stipulates the framework for its member states in regards to the civil aviation which includes AME’s and Air Crew’s licensing and further guides the states for mutual acceptance of licenses of member states. Still, it is found that the acceptance of Indian AME license holders by other regulatory bodies like FAA and EASA is found challenging due to lack of harmonization of licensing procedures, soft skills, and practical experiences. This paper aims to identify the challenges and the feasibility of Indian AMEs in the international aviation industry by analyzing the regulations stipulated by the ICAO and other prominent states. Based on the study, an economical solution is recommended that complies with international regulations and DGCA requirements.

The aircraft maintenance turnaround time is critical to airlines’ operational efficiency and profitability. This paper summarized the significance of quality control (QC) and quality assurance (QA) processes on aircraft maintenance turnaround time. The paper adopts a mixed-methods approach that combines a literature review and quantitative data analysis from a large-scale survey of maintenance personnel working in the aircraft maintenance domain within the airline industry. The results show that QC has a comparatively higher impact on lowering turnaround time of aircraft maintenance. The paper also identifies some best practices for improving QC and QA in the aircraft maintenance industry, such as standardization, automation, collaboration, training, and regulation. Conclusions in the paper include recommendations for improving aircraft maintenance quality and efficiency.

This review paper focuses on the technological developments taking place in the battle tanks used in defence technology. Battle tank is the primary offensive weapon. A tank must have high firepower to destroy enemy target with self-protection and mobility. To achieve these performances the design of a battle tank plays an important role. Various challenges need to be addressed during the development of battle tanks include protection, armament and firepower design, vibration control, providing necessary crew comfort, ammunition safety, gun barrel, suspension, and track design. Design constraints puts limitations for the realization in their development. These constraints are weight capacity, performance, and transportability. The objective is to review the design process parameters and how these are realized during a battle tank manufacturing.

The mechanical structure forms a crucial element of any engineered system as it determines the operational life of the system. For instance, the service life of an aircraft is decided by the properties of the airframe and the wings, and continuous loads acting on these structures can cause deterioration in their structural integrity. It thus becomes crucial to monitor the “health” of the structure to ensure that phenomena such as cracks can be quickly detected, and suitable corrective actions can be taken. This process is termed structural health monitoring (SHM), and it has received significant attention by industry. The SHM system involves the observation of a system over time using periodically sampled dynamic response measurements from an array of sensors and analyzing these measurements to determine the current health of the system. Traditionally, SHM has been conducted using techniques which require the system to be idle. In addition, the SHM of larger structures will require a proportionally large number of sensors to be used at certain locations in the structure. Thus, there is a need for an in-situ SHM solution which uses fewer sensors. The in-situ constraint thus requires that the structure health be monitored even in the presence of unknown inputs. To solve these problems, in this work, an unknown input observer (UIO)-based SHM solution is provided. This approach uses results from control theory and is demonstrated for a cantilever beam structure approximated as a set of two coupled spring-mass systems. It is assumed that the displacement and velocity of only one of these masses, on which the unknown input acts, are measured, and the states of the other mass are estimated based on these measurements. The advantages and limitations of the UIO-based in-situ solution are highlighted.

The issue of jet noise pollution from major airports has become increasingly significant. Recent research has indicated that incorporating a geometry-optimized chevron nozzle can effectively reduce jet acoustic power levels. Herein, we conduct a diagnostic investigation into the acoustic power levels of four different chevron nozzles. In silico studies are performed using a validated steady three-dimensional density-based k-ε turbulence model. Our findings reveal that among the four chevron nozzles (sharp, square, flat, and round edge), the implementation of a round-edged chevron proves to be the most effective design choice for mitigating jet noise in transonic aircraft. This design reduces the acoustic power level by 10% when compared to the base model of a classical high-subsonic/transonic nozzle (without chevron), while still maintaining the benefits of momentum thrust. The results of this study contribute to advancements in aero-acoustic research and provide valuable insights for the design optimization of chevron nozzles for transonic aircraft.