Car Body Frame Research Articles

FrameGraph: A Scalable Performance Evaluation Method for Frame Structure Designs Using Graph Neural Network

Abstract Multilayer perceptron (MLP) and convolutional neural network (CNN) encounter a critical scalability issue when applied to the performance evaluation task for frame structure designs. Specifically, a model of MLP or CNN is limited to structures of a particular topology type and fails immediately when applied to other topology types. In order to tackle this challenge, we propose a scalable performance evaluation method (called FrameGraph) for frame structure designs using graph neural network (GNN), offering applicability to a wide range of topology types simultaneously. FrameGraph consists of two main parts: (1) Components and their connections in a frame structure are denoted as edges and vertices in a graph, respectively. Subsequently, a graph dataset for frame structure designs with different topologies is constructed. (2) A well-defined GNN design space is established with a general GNN layer, and a controlled random search approach is employed to derive the optimal GNN model for this performance evaluation task. In numerical experiments of car door frames and car body frames, FrameGraph achieved the highest prediction precisions (96.28% and 97.87%) across all structural topologies compared to a series of classical GNN algorithms. Furthermore, the comparison with MLP and FEM highlighted FrameGraph's significant efficiency advantage. This verifies the feasibility and optimality of FrameGraph for the performance evaluation task of frame structures with different topologies.

Intelligent identification of differential subgrade settlement of ballastless track system based on vehicle dynamic responses and 1D-CNN approach

The millimeter-scale deformation control standards of high-speed railways make the monitoring and identification of subgrade settlement a key technology, especially for ballastless track systems. Addressing the uncoordinated deformation between track and subgrade caused by high track stiffness, this paper proposes an intelligent identification method for subgrade settlement based on vehicle vibration signals and deep-learning technology. Firstly, a high-speed vehicle-ballastless track-subgrade coupled dynamics model considering the track-subgrade nonlinear contact state is utilized, to obtain various vibration responses of the vehicle subsystem due to differential subgrade settlement. After data preprocessing, a multi-channel one-dimensional convolutional neural network (1D-CNN) is established to extract features from the vehicle vertical acceleration dataset and output subgrade settlement status automatically. Finally, the robustness of the model is verified using Gaussian white noise. The research indicates that the vertical accelerations of the car body and bogie frame contain dynamic characteristics caused by medium-long wavelength settlements, while the vertical acceleration of the wheelset is more sensitive to short-wavelength settlements. It is feasible to identify the degree of subgrade settlement using car body, bogie frame and wheelset vertical accelerations as parameterized multi-source input of the 1D-CNN network. The three-channel input model significantly improves the identification accuracy and demonstrates the robustness against noise interference compared to the single-input and dual-input models. This method can effectively enhance the identification capability of ‘concealed’ subgrade settlements in high-speed railways, offering a scientific methodology for status maintenance of ballastless track lines.

Ductile failure behaviour characterisation of HRT with GISSMO and crashworthiness optimisation design of VRB-HRT

In this paper, a generalised incremental stress state dependent damage model (GISSMO) is used to accurately characterise the ductile failure behaviour of hot formed steel under collision, which is the excellent material selection to improve the crashworthiness and lightweight level of car body frames. The deformation patterns, structural failure patterns, and key crashworthiness indexes of B1500HS hot-rolled tube (HRT) are validated by the comparative researches between experiments and simulations. To fully exploit the lightweight potential of HRT, a variable-thickness rolled blanks hot rolled tube (VRB-HRT) is proposed to perform its crashworthiness optimisation design with considering the ductile failure by the extended hybrid cellular automaton for VRB thin-walled structures (eHCA-VRB) algorithm. It is found that the optimal case of VRB-HRT with considering the ductile failure is easier to meet the actual performance constraints, even though possesses a lower weight reduction ratio. Therefore, the ductile failure of VRB-HRT should be considered to guarantee the structural reliability by a more reasonable optimal design.

The random dynamic performances of EMUs with polygonal damages

Polygonalization is a typical non-uniform wear phenomenon that affects the performance and comfort of the vehicle/track system. Therefore, the vehicle system performance could be strictly troubled by polygonal damage close to the wheel circumference at the wheel/rail contact. A 3D vehicle/track an EMU type train consisting of 8 coupled vehicles model has been established. The coupled model car body and bogie frame are considered rigid and integrated with the flexible wheelset, rail, and slab track to investigate the elastic deformation caused by the impact load induced by the wheel polygonalization. The flexible track can be incorporated into the multi-body vehicle model using the movable reference frame formulation. Uncertainty parameters are presented, such as passenger weight, wind force, coefficient friction, and suspension variation. The proposed research is validated based on the existing research work and shows excellent agreement. The simulation result deliberated the vertical wheel-rail force, wheelset acceleration, rail acceleration, rail displacement, and slab track acceleration. The results of this study show that as the wheel polygonal damage amplitude increase, the value of wheel/rail normal forces and the dynamic vibrational response of the wheelset axle increase. Additionally, polygonal wear-induced impact stresses may cause the wheelset axle to resonate. When wheel polygonal damage amplitude and uncertainty parameters are corporate into the system dynamics, the maximum magnitude of the wheelset, rail, and slab track acceleration increases. Besides, the train failure degree is comparable to the polygonised wheel harmonic order, defect parameters, and amplitude of out-of-roundness.

Design of Intelligent AGV Transport Car

Unmanned Guided Vehicle (AGV) is a new type of mobile robot that was applied in various fields. Aiming at the design of dedicated AGV transport vehicle for complex road conditions, this AGV transport vehicle is composed of chassis, traveling mechanism, lifting device, and removable components. By designing and analyzing the mechanical structure of the AGV transport vehicle, and it’s combined with statics theory, and the feasibility of the trolley structure is designed and discussed. The three-dimensional model of AGV transport vehicle is established by Solid Works software, and the cloud diagram of the stress and deformation of the wheel system structure is analyzed by Solid Works Smillation, and the traveling mechanism of the trolley is analyzed by statics. The rationality of the wheel system structure is verified by the deformation cloud diagram of the AGV transport vehicle under various working conditions. Based on the mathematical model optimization of variable density method, the car body frame is optimized and designed to these materials of car body. The design of the track tensioning structure and frame is obtained according to the four general engineering parameters of TRIZ theory. Finally, the modeling design of intelligent AGV transportation car is carried out by using the principles such as division, color change, and dimension change, etc. In order to facilitate the take-off and landing loading and unloading of goods for AGV transportation lifting device, and it is changed to the traditional handling mode of manpower-operated machines.

Subdomain hybrid cellular automata method for material optimization of thin-walled frame structure under transverse impact

In this paper, a subdomain hybrid cellular automata method is proposed to carry out the material optimization of thin-walled frame structure under transverse impact with minimum material cost, which is a typical optimal solution searching problem including many discrete variables. A nominal flow stress is introduced to convert the discrete design variables (cell materials) to be continuous for the update of cell materials. The global optimal searching ability of the proposed method is improved by the material update rule based on the step internal energy density target, which is adaptively defined during the material optimization to avoid the optimal solution jumping into a local one. PID control is employed to improve the robustness of the proposed method. The subdomain cellular automata model of a car body frame under transverse impact is constructed to separately perform the material and cost optimization by the proposed method and a parallel efficient global optimization method. The total material cost converges to CNY 1051 within 271 iterations using 32 CPUs by the parallel method and CNY 1101 within 8 iterations using 8 CPUs by the proposed method. The material optimization efficiency is significantly improved by the proposed method with good global searching ability.

Electric Car Frame Body Design Fullset Dynamo Capacity 3.000 Watt With Solidworks Modeling 2020

The problem of safety and comfort of the means of transportation is closely related to the construction of the main frame of the vehicle. In this study, the frame body of an electric car with a capacity of 3.000 watts is the object of study, in order to determine the simulation of loading on the frame body of an electric car with a capacity of 3.000 watts. The research was conducted using an experimental method with the help of the Solidworks 2020 software. The data analyzed was data from the results of testing the design drawing of a 3.000-Watt electric car body frame designed with Solidworks Software and simulated loading of 50 N, 100 N and 150 N. The simulation results of Von mises stress loading of 50 N with a maximum value of 1,670 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly that is 1,009 x 10-2 N/m2 marked with color blue on the simulation graph. The simulation results of Von mises stress loading of 100 N with a maximum value of 3.43 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 4.57 x 10-2 N/m2 is marked in blue on the simulation graph. The simulation results of Von mises stress loading of 150 N with a maximum value of 5.018 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 2.150 x 10-2 N/m2 marked with color blue on the simulation graph.

Electric Car Frame Body Design Fullset Dynamo Capacity 3.000 Watt With Solidworks Modeling 2020

The problem of safety and comfort of the means of transportation is closely related to the construction of the main frame of the vehicle. In this study, the frame body of an electric car with a capacity of 3.000 watts is the object of study, in order to determine the simulation of loading on the frame body of an electric car with a capacity of 3.000 watts. The research was conducted using an experimental method with the help of the Solidworks 2020 software. The data analyzed was data from the results of testing the design drawing of a 3.000-Watt electric car body frame designed with Solidworks Software and simulated loading of 50 N, 100 N and 150 N. The simulation results of Von mises stress loading of 50 N with a maximum value of 1,670 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly that is 1,009 x 10-2 N/m2 marked with color blue on the simulation graph. The simulation results of Von mises stress loading of 100 N with a maximum value of 3.43 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 4.57 x 10-2 N/m2 is marked in blue on the simulation graph. The simulation results of Von mises stress loading of 150 N with a maximum value of 5.018 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 2.150 x 10-2 N/m2 marked with color blue on the simulation graph.

Simulation of nonlinear characteristics of vertical vibration of railway freight wagon varying with train speed

<abstract> <p>Traditional vertical vibration models of rail vehicle usually have high degrees of freedom, which affects the efficiency of numerical simulation. Regardless of the coupling effect between the vehicle and rail, a six degree of freedom (6DOF) quarter model with vertical displacement and rotation angle is selected as the dynamic model. This accomplished by comparing the simulation results of half model and quarter model of the railway freight wagon, and the vertical vibration characteristics of the railway freight wagon when the wagon speed is changed. To further illustrate the nonlinear vibration characteristics and evolution laws of the car body and bogie frame of the freight wagon, the bifurcation diagrams, maximum Lyapunov exponent curves, axis trajectory curves, phase plane plots, Poincaré sections, and amplitude spectras are drawn and adopted to research the dynamic responses. The simulations reveal the complex vibration behavior such as periodic, quasi-periodic, multi-periodic, and chaotic motion. Some research results can help the industry to better design the speed limits of such railway freight wagons, and deeply understand or utilize the vertical vibration law of railway freight wagon in future research.</p> </abstract>

STABILITY OF FREIGHT CARS UNDER THE ACTION OF COMPRESSIVE LONGITUDINAL FORCES

Purpose. The aim of the work is: a theoretical study of the car movement stability when exposed to longitudinal forces of a quasistatic nature; determination of analytical for estimating the longitudinal loading of cars in trains; the influence analysis of simultaneous action of certain factors on the value of longitudinal forces, at which the car movement stability is still preserved. Methodology. Assessment of the freight car stability when moving at different speeds along curved track sections was investigated using the analytical method. The most unfavorable schemes for applying compressive longitudinal forces in a vertical and horizontal plane are considered. Findings. Expressions are obtained for calculating the value of the car lift resistance coefficient by the longitudinal compressive force acting on the car as part of a freight train. The calculations were carried out in an empty and loaded state with a transverse run-up of the car body frame relative to the track axis in a guiding section of 50 mm in a curve of small radius taking into account the inertia forces from the unbalanced acceleration. Originality. In a theoretical study, the effect on the movement stability of quasistatic longitudinal compressive forces depending on the change in speed and the force value, as well as the effect of friction forces at the contact point of the wheel flange and rail and the eccentricity of fastening the tail of the automatic coupler, are considered. The influence of longitudinal compressive forces on the stability of freight rolling stock when moving in a curve of small radius with speeds up to a design value of 120 km/h is investigated. Practical value. The application of the results obtained by the above method will help to increase the stability of the freight rolling stock, which in turn will allow increasing the technical speed of train movement by removing some existing limits of permissible speeds. Using the described methodology for determining the car lift resistance coefficient will allow justifying the cause of wheel derailment, as well as to develop and put into practice the technical measures to prevent the lift of carriages, thrusts and shears of the track.

Composite material components damaged by impact loading: a methodology for the assessment of their residual elastic properties

Purpose: Detection and evaluation of damage due to impact or fatigue loading in components made by composite materials is one of the main concern for automotive engineers. We focus on damage due to impact loading on long fibre, plastic matrix composite, as they represent one of the most interesting development solution for automotive components toward lightweight structure that in turn means reduction of fuel consumption and of Green House Gas emissions. Design/methodology/approach: An innovative simplified methodology is proposed, based on the impact and repeated impact behaviour of composite material, for the evaluation of the induced damage and of material residual elastic properties. The investigated composite laminate is made of eight twill-wave carbon fabrics impregnated with epoxy resin. The methodology consists of two phases: at first the identification of the impact response. Composite plates have been impacted at different energy levels and residual elastic properties measured through standard tensile tests. The relationship between impact energy and residual elastic properties is obtained. Then the exploration impact load is identified, large enough to give a well-defined picture of the suffered damage but soft enough to do not induce further damage in the composite laminate. Findings: This exploration impact test and the Damage Index (DI) value, as interpretation key, leads to a prediction of the local residual elastic properties in the damaged area. The proposed methodology has been validated on plate specimens. A strict correlation is found between the predicted and the actual residual elastic properties of the damaged composite plate. Practical implications: Subsequently it has been applied to a composite beam, with a omega shape transverse section, that can be considered as a demonstrator for a typical beam used in the car body frame. Originality/value: A selection on the following alternatives will be possible: a – don’t care the damage is not affecting the structure performance; b – repair is needed but will be sufficient; c – substitute the damaged component as soon as possible.

Estimation of dynamic performances of the safe operation of high-speed electric train

The process of implementation of new developments, in particular, new generation rolling stock holds a prominent place among the range of measures for organization of high-speed passenger rail transportation in Ukraine. The example of permission for use and the initial phase of work with interregional NRCS2 dual-mode electric trains produced by Hyundai-Rotem Corporation is the illustrative one in this context. Due to the detection of macro-cracks in bolster beams of the car body frames of these electric trains, namely in the areas of mounting of anti-yaw dampers, these trains were taken out of service until the completion of the modernization of problematic nodes. The comprehensive study on the determination of the safety parameters of electric trains was conducted to determine the causes of destruction of bolster beams. At the same time, bolster beams loading was estimated depending on the characteristics of anti-yaw dampers by means of computer simulation of the dynamics of motion of trailing and motor cars. The feasibility of selection of parameters for anti-yaw dampers mounted on electric train cars was assessed. The results of work will improve the safe operation of high-speed trains and increase the efficiency of estimates regarding the loading of bearing structures of underframes of the of rolling stock.

Topology Optimization in Electric Car Body Frame Based on Optistruct

In order to optimize the structure of the electric car body frame, the static analysis of the car frame were carried on. For the goal of the frame’s weight minimum, OptiStruct software was used to topology optimization design. And the optimal material distribution program of the frame structure was got. Static strength before and after optimization was comprehensive compared through the stress, deformation. The results showed that the weight of frame after optimization was reduced by 18.96%, and the requirements of the strength and stiffness were ensured.

DEVELOPMENT OF RECOMMENDATIONS FOR EXTENDING THE USEFUL LIFE OF PASSENGER CARS

Purpose. The vast majority of passenger car fleet of «Ukrzaliznytsia» have cars with outlasted service life. In this regard there is a need to find methods to justify the extending useful life of passenger cars and to assess the car body frame residual life conformity to the operating load for the next life time. Methodology. The selection of cars enforced technical diagnostics of cars to detect the level of corrosion and mechanical damage. The following steps provided the car body frame strength analysis on the basis of experimental static and impact strength tests, the longitudinal force effect endurance tests as well as assessment and forecasting of conformity of car body operating life for the next period. Findings The car survey before testing showed that the technical condition of sleeper cars (SSC) is better than that of open-type cars (SOC). So, in SSC cars the thinning of the main load-bearing elements due to corrosion does not exceed 10%, there are no cracks, deformations, rack breakages, etc. At the same time in SOC cars the thinning due to local corrosion reached 35%. There are deformations and corrosion damage of side sill Zshape of both cars, single corner post breakages, damage to the joints of longitudinal tie rod and span bolsters. The conducted static and impact strength tests with following strength assessment of the car structural members showed that the strength of the latter is provided according to the normative documents, and these cars pose no threat to traffic safety. The impact endurance tests showed that all the cars passed the endurance tests without damage, which would prevent from testing and could not be removed during the next depot repair or overhaul, and had life length that allows them to extend the useful life for the next period. Originality. The results of experimental studies show that passenger cars after 28 … 30 and 33… 35 years of operation meet the requirements of strength and safety in accordance with regulatory documents and allow, provided the impact endurance, reasonable extending of the car service life. Practical value. The part of the car fleet, which was to be written off based on the service life, may extend lifespan without additional measures.

Bi-level optimization for the cross-sectional shape of a thin-walled car body frame with static stiffness and dynamic frequency stiffness constraints

In usual automobile practice, the structural optimization of a car body is based on changes in the topology, the shape, the cross-sectional shape and finally the thickness size successively depending on the development stages. However, design engineers mostly rely on their experience, intuition and data accumulation when making decisions on the cross-sectional shape of a car body frame. Therefore, a bi-level structural optimization model is proposed to determine the optimal cross-sectional shapes of each thin-walled beam and to achieve a lightweight car body frame with a high stiffness. Intermediate box sections are introduced to bridge the relationships between the two levels. At level 1, the car body frame with static stiffness and dynamic frequency stiffness constraints is optimized to obtain the optimal sizes of the box section, using a sequential approximate optimization method. At level 2, arbitrarily shaped cross-sections constrained with cross-sectional properties are optimized using a genetic algorithm. Component sensitivity analysis and manufacturing constraints promote this model to be closer to actual automobile practice. Finally, a numerical example, solved by the developed software Vehicle Body – Forward Design and Optimization, verifies that the presented method is effective in guiding the conceptual design of the car body frame.

Study on Dynamic Performance of a Flying Car Body Frame Based on ANSYS

In this paper, In view of body frame of a flying car, the dynamic performance was studied.Firstly, geometry model of the body frame was built by CATIA software. Secondly, plotted in girding form was established by ANSYS software. Thirdly, loading and restraint were added on model and dynamic characteristic was analyzed. Finally, a better conclusion was obtained.

Research on Mechanical Engineering with Lightweight Design for a Car Body Frame

This paper develops a novel approach for the lightweight design of a car body frame. In this approach, the cross-sectional dimensions of a car body frame are treated as design variables. First, sampling points are created based on Latin Hypercube Sampling (LHS), and then Design of Experiment (DOE) is conducted. After that, an analysis is done to obtain those design variables affect the results most. Finally, Sequential Quadratic Programming (SQP) is utilized to solve the optimization problem while the amount of design variables is reduced according to the former analysis. The advantage of this method is that it reduces the burden of optimization algorithms and offers a practical way for the lightweight design of a car body frame.

A Lightweight Body Frame Conceptual Design of a Mini Electric Vehicle

To realize the lightweight structure, a car body frame conceptual design of a mini electric vehicle was performed with topology optimization and size optimization. Topology optimization was used to search load paths and size optimization was applied to model a simplified structure. Static stiffness, crash safety and free vibration conditions were considered simultaneously in both of the optimization phases. Due to the feature of conceptual design, crashworthiness cases were regarded as static stiffness ones with inertia relief analysis for a linear equivalent. The objective function in multi-objective topology optimization was defined by Compromise Programming Method in OptiStruct. Because of the characteristic of the geometry and the manufacturing constraints of profiles, the design variables in size optimization were defined as both continuous and discrete variables. The resultant structure outperforms the original one in many structure responses and most significantly, it reduces weight by 36%, which demonstrates the efficiency of the proposed method.

Evaluation of Sternocleidomastoid Muscle Activity of a Passenger in Response to a Car's Lateral Acceleration While Slalom Driving

Human factors are becoming one of the most important factors that are considered for automobile design and test. However, the ride comfort of a passenger or driver is mainly dependent on a subjective assessment by a test driver or questionnaire investigation, and, therefore, a quantitative evaluation of the ride comfort is being pursued as one of the research goals in the automobile industry. In this paper, actual-vehicle and driving simulator (DS) experiments were carried out to evaluate the sternocleidomastoid (SCM) muscle activity of a passenger in response to a car's lateral acceleration while slalom driving. Interestingly, the SCM muscle of the passenger on the side opposite the direction of the car's lateral acceleration contracts to keep the head stable against the body shaking. The electromyography (EMG) signal of the SCM muscle in a modified car was significantly lower than in a normal car, because the 1-10 Hz low-frequency vibrations of the body frame of the modified car during the slalom driving were decreased through improvements of the rigidity of car's body frame. A passenger feels more discomfort when the EMG signal of the SCM muscle increases, and less as the signal decreases. The DS experiment, with the addition of more experimental conditions, arrived at the same conclusion, which testified that the DS is a powerful tool with which to evaluate passenger discomfort. In conclusion, the EMG of the SCM muscle can be considered as an objective and effective method with which to quantify the effect of vehicle properties on human discomfort in both actual-vehicle and DS experiments for slalom driving.

725 鉄道車両の車体断面せん断変形をともなう弾性振動低減対策の検討 : コーナーブレースの適用効果

The previous studies, referring to improving the ride comfort of railway vehicles related to the carbodies' vertical bending vibration, generally focus on reducing so-called "first bending mode" of the carbody. However, not only the first bending mode of the carbodies, but the vibration with their shear deformation (i.e. the vertical section of the carbody becomes a rhombus shape) often affects the ride comfort of passengers. In this study, the authors have proposed "corner braces" which combine the floor/roof structures with the side structure to constrain the deformation of the section of the carbody. Excitation tests on the rolling stock test plant have been carried out for two types of test vehicles with stainless steel carbodies, one of which is carbody frame alone and the other is the complete vehicle with the same condition as the commercial commuter type vehicles. The effect on the carbody made of the aluminum alloy, have also been investigated by the normal mode analysis with the finite element model (FEM). The results of the excitation tests or the numerical analysis have shown that the proposed corner braces successfully improve the rigidity of the carbodies and the natural frequencies of the carbody have risen.