Vehicle Structure Research Articles

Axial quasi-static crushing of composite tubes: An investigation on the influence of the modeling techniques

Carbon fiber-reinforced plastic (CFRP) composites perform remarkably as crashworthy structures in transport vehicles. They promise to improve the crashworthiness of vehicles in addition to weight savings thanks to their superior strength-to-weight ratio. However, designing composite crashworthy structures is challenging since predicting the energy absorption values and crushing behavior are not straightforward. Finite element modeling is a very effective numerical technique to predict energy absorption values and shorten the design process of composite structures, yet it is also quite hard to simulate the crushing of composite structures due to their complex damage mechanisms. This paper presents an investigation of the axial crushing behavior of composite tubes made of woven fabric CFRP and the influence of the different modeling techniques. Macro-scale stacked shell modeling approach is adopted to model the composite tubes. Various virtual debris wedge models are incorporated to obtain realistic failure modes in simulations. Simulated crushing morphologies and energy absorption values are compared with the experimental test results. Furthermore, the prediction capability of the models and the influence of mesh geometry used for rigid flat platen crushers are examined. It is found that the geometry of the virtual debris wedge and mesh geometry of the flat platen crusher affect the simulated crushing modes and level of the absorbed energy predicted.

The Effect of Landing Gear Dimension Variation on the Static Strength and Dynamic Response of Unmanned Aerial Vehicle (UAV)

This research discusses the static and dynamic analysis of the landing gear structure of an unmanned aerial vehicle (UAV). The dimensional study is conducted to investigate the effect of landing gear dimension variation on UAVs’ static strength and dynamic response. Static analysis was performed with Finite Element Method (FEM) software. The dynamic response of the UAV is analyzed using a single-degree-of-freedom vibration model. Based on the static analysis results, the landing gear stiffness and strength can be increased by increasing the width and decreasing the height, radius, and length of the landing gear structure. The energy dissipation in the dynamic analysis is described by hysteresis and viscous damping model. The dynamic response simulation results show that the increase in the stiffness of the landing gear leads to an increase in force transmission and acceleration of the UAV. Furthermore, the UAV response using the viscous damping model can accurately predict the system’s response with the hysteretic damping model for small damping conditions. However, the deviation was observed for large damping conditions.

Integrated Design and Flight Validation of Solar-Powered Unmanned Aerial Vehicle (UAV) Structure and Propulsion System

The development of solar-powered unmanned aerial vehicles (UAVs) primarily focuses on enhancing the efficiency of the propulsion system to minimize energy consumption during the conversion of valuable solar energy. However, due to the unique nature of UAV propulsion systems, there is limited cross-reference ability among existing solar-powered UAV systems. This paper proposes an integrated design approach for the propulsion system and UAV structure. Based on this approach, an overall design is conducted for the solar-powered UAV, including initial design goals and performance parameters. Aerodynamic layout design and performance estimation are carried out, and a prototype is fabricated and assembled for flight testing validation. The results demonstrate the significant importance of this approach in improving the efficiency of the solar-powered UAV propulsion system.

Radiation-Hardened and Flexible Pb(Zr0.53Ti0.47)O3 Piezoelectric Sensor for Structural Health Monitoring.

Piezoelectric sensors are excellent damage detectors that can be applied to structural health monitoring (SHM). SHM for complex structures of aerospace vehicles working in harsh conditions is frequently required, posing challenging requirements for a sensor's flexibility, radiation hardness, and high-temperature tolerance. Here, we fabricate a flexible and lightweight Pb(Zr0.53Ti0.47)O3 piezoelectric film on flexible KMg3(AlSi3O10)F2 substrate via van der Waals (vdW) heteroepitaxy, endowing it with robust ferroelectric and piezoelectric properties under low energy-high flux protons (LE-HFPs) radiation (1015 p/cm2). More importantly, the Pb(Zr0.53Ti0.47)O3 film sensor maintains highly stable damage monitoring sensitivity on an aluminum plate under harsh conditions of LE-HFPs radiation (1015 p/cm2, flat structure), high temperature (175 °C, flat structure), and mechanical fatigue (bending 105 cycles under a radius of 5 mm, curved structure). All these superior qualities are suggested to result from the outstanding film crystal quality due to vdW epitaxy. The flexible and lightweight Pb(Zr0.53Ti0.47)O3 film sensor demonstrated in this work provides an ideal candidate for real-time SHM of aerospace vehicles with flat and complex curve-like structures working in harsh aerospace environments.

Study on Ground Experimental Method of Stagnation Point Large Heat Flux of Typical Sharp Wedge Leading Edge Structure

In this paper, aimed at the problem of large temperature gradient thermal testing with the typical sharp wedge leading edge structure of a hypersonic vehicle, a subsonic high-temperature combustion gas heating (SHCH) test device is used to conduct a series of experiments on the heat flux simulation ability of subsonic high-temperature combustion gas in the stagnation point region. Firstly, for a hypersonic vehicle with a flying height of 24 km and Mach number range of 4~6.5, the stagnation point heat flux in the head area is obtained by numerical calculation of a typical leading edge structure, which is used as the experimental target of the thermal structure test. Secondly, an experimental specimen with a Gardon heat flux meter is designed with the same shape and size as the specimen in the numerical simulations to prepare for the subsequent SHCH test. Thirdly, a method to determine the combustion gas temperature based on a Kriging surrogate model is proposed. CFD numerical simulation is conducted using the SHCH test model, and the numerical calculation results are used as the training dataset. The Kriging surrogate model is used to establish an approximate fitting relationship between the stagnation point heat flux and experimental parameters under SHCH conditions. The corresponding combustion gas temperature values are found, respectively, with the hypersonic aerodynamic heat flux at Mach 5.0~5.4 as the target value. Finally, stagnation point heat flux testing of low-speed and high-temperature combustion gas is performed at different combustion gas temperatures. The experimental and target values obtained from hypersonic aerodynamic thermal simulations are compared and analyzed to verify the heating capacity of SHCH and the feasibility of hypersonic aerothermal simulation testing.

Control and Optimization of Pre-Transmission Parallel Hybrid Vehicle with Fuzzy Logic Method and Comparison with Conventional Rule Based Control Strategy

In this study, a model of a pre-transmission parallel hybrid vehicle was created in MATLAB/Simulink environment. A torque control strategy has been developed for the hybrid vehicle on the created model. The hybrid vehicle's torque control is provided by fuzzy logic and conventional rule-based control strategies. The control strategies of the hybrid vehicle have been developed based on four input parameters: accelerator and brake pedal position, battery state of charge and the operating mode of the electric motor. The regenerative braking system of the pre-transmission parallel hybrid vehicle has been provided with a fuzzy logic control strategy in both vehicle structures. In the fuzzy logic torque split controller, a control algorithm has been created in which the safety, performance and fuel consumption values of the vehicle meet at the optimum point. Under different driving cycle conditions, the effects of control strategies on engine operating points have been examined and average fuel consumption values have been obtained. In the control of the parallel hybrid vehicle with fuzzy logic method, it has been obtained that it provides 12.87%, 6.62%, 2.27% and 6.23% fuel savings under FTP-75, NEDC, EUDC and ECE-15 driving cycle conditions, respectively. It has been observed that the vehicle cannot provide sufficient performance in US06 driving cycle conditions with the use of conventional rule-based control strategy.

AUTOMOBILE CRANES QUANTITY DETERMINATION FOR MAIN GAS PIPELINES CONSTRUCTION AND REPAIR

Russia’s dominance in the global energy market is predetermined by the scale and development prospects of gas transmission infrastructure to ensure a continuous cycle of gas supply from fields to end consumers. Operating conditions of gas production, processing, transportation, storage and distribution facilities are associated with the influence of environmental factors, which varies greatly due to the length of pipelines covering all climatic regions of the country. The growth in the length of new pipelines and the need to repair existing pipelines based on the results of in-line diagnostics contribute to an increase in the volume of loading and unloading operations and the storage of pipes, therefore, studies on improving methods for determining the need for truck cranes when for constructions organizing technological processes and repair of main gas pipelines are relevant.
 The purpose of the study is to determine the efficiency of truck cranes operation in the process of main gas pipelines overhaul and construction.
 The scientific novelty is formed by the patterns of formation of the cost and labor intensity of loading, depending on the load capacity of a truck crane and the unloading pipes parameters.
 The research methodology is based on a systematic approach, methods for analyzing the technical operation of vehicles and proven data processing techniques.
 The recommendations made as a result of this study have been implemented to organize preparatory work at major main gas pipelines overhaul facilities and construction, which increases the efficiency of processes, optimizes the structure of special vehicles and reduces the cost of technological operations.

Study on the deformation of inter-rib shell plate of reinforced conical shell structure under deep-water-explosion loading

The reinforced cylindrical and conical column structures are widely used structural forms in underwater vehicle structures. In this paper, the reinforced conical shell structure in the transition compartment of underwater vehicles was used as the research object. Based on the shock wave propagation theory and ABAQUS acoustic structure coupling numerical simulation method, the numerical simulation model of conical shell structure under deep-water explosion load was established.The deep-water explosion simulation of conical shell structure under the conditions of different water depths, charges and explosion distances was carried out, and the deformation and failure mode of small depressions in the shell plate between ribs of stiffened conical shell structure was obtained, that was, independent small pits were formed along the axis direction. According to the theory of elastic-plastic deformation of plate and shell structure, the small pits of shell and plate between ribs were approximated as the deformation of trapezoidal plate, and the deformation function of trapezoidal plate was obtained by coordinate transformation. The deformation energy of plate and shell was divided into bending deformation energy and midplane strain energy. By establishing the correlation between explosion energy and deformation energy, the theoretical calculation model of the small pit deformation mode of shell and plate between ribs was obtained.

Determination and Static Analysis of the Chassis Model for Electric Vehicles

Vehicle technology with an internal combustion engine emerged at the end of the 19th century. Although it is not very well known, the first prototype studies of the electric vehicle coincide with the same period. Today, factors such as global warming, pollution and the decrease in fossil fuel reserves accelerate the transition to electric vehicle technology. In this context, a new system structure is needed for electrically driven systems differently from traditional vehicle structures. In this study, a chassis design for an electric vehicle is carried out. While designing, the part where the battery pack will be placed has been modeled and simulated with the help of the ANSYS program to protect the battery and electronic components that are particularly sensitive to impacts. In order to be successful in abuse tests such as Crush and Crash tests specified in the regulations and standards, the material selection and design should be done correctly. In this context, the right materials are determined as a result of the researches and 3D simulations are made and crash tests are carried out in the simulation environment. As a result, tube type chassis was chosen among many chassis models and 7079 aluminum alloy was found suitable as raw material. According to the simulation results, it is seen that the design and the selected alloy are suitable.

Optimal Design of Electric Motorcycle Tubular Frame using Topology Optimization

This paper proposes a methodology for designing motorcycle tubular frames using simulation software such as MATLAB/Simulink and ANSYS, which provides an efficient and cost-effective way to approximate loads acting on the structure and topology optimization to meet performance and safety requirements. Using these tools, the design process can be simplified and reduce the number of costly physical prototypes and tests. The multi-body model developed in MATLAB® Simscape was used to approximate the loads and boundary conditions on the frame, while the ANSYS software was used for topology optimization. The resulting motorcycle frame was found to weigh 9.48 kg. The simulation results also showed that the proposed frame design met the required safety and performance criteria. The methodology presented in this paper is not limited to electric motorcycle tubular frames and can be applied to other types of vehicle frames or structures. The use of simulations allows for the exploration of different design options and the identification of optimal solutions with minimal cost and effort. The combination of MATLAB® Simulink and ANSYS is a powerful tool for the design and optimization of complex structures, providing accurate results and saving valuable time and resources.

Mathematical modelling of gear upshift and downshift schedule for two-wheeler amt transmission

Gear shifting strategy is the key for the successful working of an automated manual transmission (AMT) as it affects the driving experience, fuel economy and dynamic performance of the vehicle. Depending upon the driver’s requirement, AMT can be designed for maximum acceleration performance and fuel efficiency. This project involves generation of gear shift schedule for both the maximum acceleration and fuel economy performance. To generate the gear shift schedule, a mathematical model is developed in MATLAB environment which takes input parameters as: vehicle speed, acceleration and throttle position. For generation of gear upshift schedule for maximum acceleration and fuel economy equation relating acceleration with tractive forces and vehicle’s fuel consumption equation at different throttle position is used respectively. Fuel consumption equation relates to brake specific fuel consumption (BSFC) along with vehicle structure. In order to obtain BSFC data, a GT-SUITE model of motorcycle is developed which incorporates data like gear ratio, power, torque and motorcycle weight. Finally, a buffer zone is applied to generated upshift schedule for both maximum acceleration and fuel economy case to get the downshift schedule. The generated gear shift schedule can be utilized for the development of the retrofit AMT kit on manual transmission motorcycle.

Research on the Modified Echo Highlight Model for Underwater Vehicles with Combined Structures

Abstract The highlight model is widely used as a simple and convenient method in the radar field but its accuracy is not high. Based on the traditional highlight model, the algorithm has been improved to address the acoustic scattering problems of underwater vehicles with more complex line shapes. The basic idea is to partition the model into micro-bodies to calculate the scattered sound pressure, consider the phase interference of each part, and then synthesise the scattered sound pressure to approximate the target’s actual shape. A computational model of the wedge-shaped convex structure on the back of the underwater vehicles is developed using a highlight model of a trapezoidal plate. The results of the calculations using the highlight model approach are consistent with those of the planar element method. Utilising the modified highlight model method, the accuracy of acoustic scattering characteristics calculations for the stern and overall structures of underwater vehicles has proven satisfactory. Finally, fast acoustic scattering prediction software is developed for underwater vehicles, enabling the calculation of the acoustic scattering characteristics for individual structures, combined structures, and coated silent tiles. This software provides algorithmic support for the fast prediction of the acoustic stealth performance of underwater vehicles.

Multi-objective robust optimization of foam-filled double-hexagonal crash box using Taguchi-grey relational analysis

In this paper, a novel thin-walled double-hexagonal crash box is first proposed and then multi-objective robust optimized for better overall crashworthiness under multi-angle impact loading, using a proposed hybrid method combining aluminum foam-filling and Taguchi-grey relational analysis (GRA). Specifically, the finite element (FE) models of the regularly-shaped double-hexagonal column (DHC) extracted from original irregularly-shaped crash box under multi-angle impact loading, including hollow (H-DHC) and foam-filled (F-DHC), are first built and validated by experiments. On this basis, a comprehensive crashworthiness comparison is conducted to explore relative merits of F-DHC over original H-DHC under multi-angle impact loading. After that, the F-DHC is multi-objective robust optimized for maximizing overall specific energy absorption (SEAθ) and minimizing overall initial peak crushing force (IPCF0) simultaneously under multi-angle impact loading, using a hybrid method of Taguchi-GRA. At last, a bumper-crash box integrated crashworthiness analysis under multi-angle impact loading is executed to further verify the optimization. The optimal F-DHC and the optimized crash box within the optimal F-DHC demonstrate evident improvement of crashworthiness compared to their respective initial designs, indicating aluminum foam-filling combined with Taguchi-GRA could be an effective approach for multi-objective robust optimization of the novel crash box and other similar vehicle structures.

Designing discrete-time control-based strategies for pursuit-evasion games on the plane

Two-player discrete-time pursuit-evasion games are proposed with control-based strategies on the plane, where each player's position is determined by the discrete-time version of the kinematic equation related to the moving structure of vehicles. In this regard, the first game is built in a one-target fashion where the high-speed pursuer tries to reach the running evader in optimal discrete time, whereas the second game is constructed from a two-target perspective where the evader becomes an attacker whose ultimate aim is to build a control-based strategy to capture the high-speed pursuer who follows the shortest tracking policy within his target region. Each player's winning and losing strategies are designed under certain playability conditions. Later, the main results are generalized for players sharing various discrete-time speeds during the game. The motivation of the study is to investigate the losing and winning strategies of the evader against the high-speed pursuer, who tries to capture his opponent in optimal discrete time on the plane. Numerical experiments are performed on four different unmanned aerial vehicles (UAVs) flying at the same altitude with various airspeeds and turning radii, where several capture scenarios and control-based strategies for each UAV are constructed according to the main results.

Modeling of local electrode stresses and pressures in lithium-ion battery packs using three-dimensional homogenization

Battery packs in electric vehicles consist of several battery modules, each containing several battery cells with numerous layers (electrodes, separators and current collector layers. A finite element model that can capture the stresses on the layer level would be extremely large in order to resolve the details. In the present paper, a novel homogenization method is presented which is based on three-dimensional laminate theory. The number of finite elements for the simulation of stresses in batteries can in this way be drastically reduced. Based on a homogenized solution, layer-level stresses can then be determined in a post-processing step. The present formulation is adaptive and fast, eliminating the need to model individual layers. It allows for non-linear elastic behavior of active layers that undergo swelling and separator layers as well as elastic-plastic behavior of current collectors. Three realistic battery structures subjected to swelling in electrode layers have been simulated: 1. free jellyroll, 2. jellyroll enclosed by a stiff enclosure, and 3. battery module consisting of 10 cells. The presented homogenized method allows for the inclusion of battery cells as parts of larger models representing vehicle structures and facilitates studying the interaction between batteries and surrounding structures.

A damage sequence interaction model for predicting the mechanical property of in-service aluminium alloy 6005A-T6

In the long-term service process, materials and structures will bear fatigue, ageing, and other degradation behaviours under environmental factors such as temperature, vibration, and radiation. Service damage makes materials and structures gradually deviate from the original design expectations. In this study, the material is decoupled into a two-phase system consisting of matrix and void phases. The different mechanical behaviours of material by the evolution of the void phase are analysed under the premise of the constitutive uniqueness of the matrix phase. Different characterisation methods of damage are discussed, and a finite element analysis–test combination method is proposed to identify the damage evolution function and the undamaged hardening, avoiding the influence of the necking effect and the accuracy of the test apparatus. A damage interaction model associated with the physical mechanism of microstructure evolution is constructed based on the ductile damage evolution function, discussing the influence of different damage definitions on the sequence interaction. The aluminium alloy 6005A-T6 commonly used in car body structures of rail vehicles is studied. The damage evolution function and undamaged hardening are established by testing undamaged specimens and verified by testing service-damaged specimens that bore a certain service loading. Then the damage interaction mode was determined. The proposed damage sequence interaction model provides an effective non-destructive testing method to obtain the hardening behaviour of in-service engineering materials. It can also extend to various existing constitutive equations.

Quasi‐static axial crushing of multi‐tubular foam‐filled carbon fiber reinforced composite structures

AbstractIn automotive design, a key aspect in limiting injuries in the event of collision is the ability of vehicle's structures to absorb high quantities of energy. Recently, automobiles have been designed with materials such as carbon fiber‐reinforced polymers to replace the conventional metallic materials, to boost structural safety and fuel efficiency. In this study, various combinations of carbon fiber‐reinforced plastic and Kevlar‐reinforced polymer composite tubes were assembled to form multi‐tubular composites and their crushing properties were investigated under quasi‐static axial compression. A total of five different combinations were designed and tested. The results showed that the addition of intermediate tubing system in the hollow composite tubes significantly improved the load‐bearing and energy absorption capabilities of the composite tubes. In addition, these configurations were also filled with polyurethane (PU) foam. It was shown that, apart from specific energy absorption (SEA), all the other parameters, such as peak load, mean load, crushing force efficiency, and overall energy absorption ability, were enhanced with the addition of foam. The SEA parameter showed inconsistent behavior, and this was attributed to the weight addition caused by the addition of foam in the composite tubes.Highlights This study examined the crashworthiness properties of multi‐tubular structures. Placing of intermediate tubing showed great improvement in absorption capacity. The system with carbon‐based intermediate tubes performed the best. Filling PU foam within the structures also improved the load‐bearing properties. The SEA was seen to reduce with the addition of PU foam.

Thermo-Structural Response Prediction of UHTCC Control Surface for Hypersonic Cruise Vehicle

One of the most complex issues that govern the design of a hypersonic vehicle is aerodynamic heating which is much more severe for an air-breathing vehicle as it operates within the atmosphere for longer durations. Due to the detrimental impact of aerodynamic heating on the vehicle structure, it is imperative to develop a robust thermal protection system that can protect the vehicle from high temperatures. However, the development of sophisticated TPS for slender components is impractical and, therefore, requires a hot structure system that can operate at substantial aerothermal loads. The aim of this study is to predict the impact of aero-heating on a UHTCC-based hot structure system of a hypersonic cruise vehicle through uncoupled thermo-structural analysis of the control surface. Validation of numerical methods implemented is done through literature comparison and grid independency tests.

Enhancing the Performance and Durability of Commercial Vehicle Cargo Box Frames through Modal Analysis

The cargo box frame (CBF) is the main structure of a commercial vehicle designed to handle loads and components during travel. The chassis is subject to vibrations caused by rough roads and the components mounted on it. This study proposes a procedure for analyzing and validating CBF structures using a combination of non-destructive modal analysis and finite element analysis to investigate the vibration characteristics of the four-wheel CBF, including its natural frequency and mode shapes. The CBF’s response to various load conditions, including stress distribution and displacement, was analyzed. The results show that the actuation frequency can affect a truck’s chassis due to the CBF’s natural frequency falling within the excitation range. The resulting mode shape can improve CBF strength, reduce weight, identify defective welds, and determine optimal mounting locations based on the center of gravity (CG) for components such as side-swing doors and cold room panels.

Application of laser welding to STS301L side structure of railway vehicles (II) - incidence angle welding conditions for laser beam based on multiple regression analysis of dummy variables

Application of laser welding to STS301L side structure of railway vehicles (II) - incidence angle welding conditions for laser beam based on multiple regression analysis of dummy variables