Passenger Car Bodies Research Articles

Analysis of stress state of passenger car bodies

Analysis of stress state of passenger car bodies

Analysis of procedures for assessing the technical condition of passenger car bodies after post-accident repairs

The rapid development of the automotive industry is associated with a large number of motor vehicles on public roads. As the number of active road users increases, the probability of a road accident increases. As a result of a collision, cars have minor or major damage, often related to damage to the vehicle's body structure. The paper discusses issues related to the assessment of the quality of post-accident repairs and their impact on the technical condition of the post-accident vehicle in further operation.

ОБОСНОВАНИЕ ПРОЧНОСТИ НЕСУЩЕЙ КОНСТРУКЦИИ КУЗОВА ВАГОНА С УЧЕТОМ КРИТИЧЕСКИХ НАПРЯЖЕНИЙ В ГОФРАХ

The issues are considered that are connected with substantiating the strength and stability of the metal structure of a double-deck passenger car body under the influence of both compressive loads and the effects of excessive solar radiation and other external factors. 
 A computational and experimental method is proposed for assessing the stability of corrugated sections of the roof slopes of passenger car bodies. Five variants of the structural design of the double-deck car roof covering are proposed. The stability of the covering for the accepted variants was evaluated by an analytical method using a tabular and rod finite element model. Based on the results of the calculation, a rational variant of the structural design of the car roof was determined. 
 The results of theoretical studies are confirmed by the data of full-scale bench tests of the metal structure of a new double-deck car body.

МЕТОД ИССЛЕДОВАНИЯ НАГРУЖЕННОСТИ КУЗОВОВ ПАССАЖИРСКИХ ВАГОНОВ С ДВУХСЛОЙНОЙ ОБШИВКОЙ БОКОВЫХ СТЕН

A method is proposed to estimate the loading capacity of passenger car bodies with two-layer side wall lining using the finite element method and mathematical modeling of the car movement along real track irregularities. The interaction of the side wall lining sheets connected by spot welding is described. Various types of two-layer lining are considered. The estimation is given to the influence of the method of the two-layer lining on the stress-strain state obtained by finite element calculation according to the dynamic parameters of the car when modeling its movement along real track irregularities. It is found out that when estimating the stress-strain state in the zones of welded joints, it is advisable to use detailed design diagrams with modeling of their geometry. When assessing the strength of the body bearing structure or the stress-strain state of large body components, it is advisable to use design diagrams describing welded joints with special rod finite elements. When assessing the dynamic characteristics of a car moving along the track irregularities using a hybrid dynamic model, design diagrams with the description of a two-layer lining with orthotropic materials are applied. Also, when using appropriate design diagrams in these types of studies, a sufficient degree of results accuracy obtained is ensured.

РАСЧЕТНО-ЭКСПЕРИМЕНТАЛЬНАЯ ОЦЕНКА ПРОЧНОСТИ ПАССАЖИРСКОГО ЭКСКУРСИОННОГО ОБЗОРНОГО ВАГОНА МОДЕЛИ 61-941

Experiment-calculated evaluation of the strength of the load-bearing body metal structure of a passenger observation car model 61-941 is done. The car is designed for tourist and sightseeing passenger trips. The project is created on the basis of a serial passenger car model 61-4179 as part of the capital repairs by Tambov Railway Car Repair Plant VRM. In accordance with the design andengineering specification, the body of the base car was significantly modernized, new planning solutions were applied for the internal equipment of the car, the frame of the car body was strengthened. Some theoretical studies using the finite element method were carried out to assess the compliance of the observation car model 61-941 with regulatory requirements. The strength and stability of the body metal structure is evaluated. At the second stage, full-scale tests of the car were carried out in static and dynamic conditions with longitudinal collisions. Additional attention is paid to the attachment points of passenger seats to the elements of the car body. The analysis of the results of theoretical and experimental studies shows their satisfactory compliance with the requirements of regulatory documents required for passenger car bodies.

Determination of the efficiency of the modernization of passenger car bodies

The authors determined the intensity of the increase in wear of various elements of the body. It has been established that the lower trim, the roof slope and the lower part of the side wall have the greatest wear. It is proposed to use aluminum alloys for the modernization of passenger car bodies. The advantage of such a technical solution is an increase in the corrosion resistance of the body. The reduction of tare allows to reduce the specific resistance to train movement, reduce fuel and electricity costs for train traction. To reduce operating costs using the basic provisions of the locomotive traction theory, calculations were made to determine the energy consumption for the movement of a passenger train according to the profile conditions of the real section of the regional branch of the Southern Railway by diesel and electric locomotive traction with the base variant and the variant of passenger cars with reduced tare weight) in composition of the train. It has been established that the annual savings in energy costs for the traction of passenger trains when using passenger cars with a reduced tare weight is about 1 million UAH.

TO THE ISSUE OF MODERNIZATION OF PASSENGER CAR BODIES

Passenger cars owned by JSC "Ukrzaliznytsia" have practically exhausted their resource. Improving the efficiency of railways requires the use of new innovative technical solutions. The article analyzes the technical condition of the bodies of passenger cars that have worked out their resource. A total of 540 wagons of different years of construction were inspected. In the course of the analysis, the results of inspections of the metal structures of cars were divided into five conditional groups depending on the service life. At the same time, the nominal values of the thicknesses of the structural elements of the car and the actual values were compared. The authors determined the intensity of the increase in wear of various elements of the body. It has been established that the lower trim, the roof slope and the lower part of the side wall have the greatest wear. It is proposed to use aluminum alloys for the modernization of passenger car bodies. The advantage of such a technical solution is an increase in the corrosion resistance of the body. This significantly increases the durability of the wagons and reduces the tare weight of the car. The reduction of tare allows to reduce the specific resistance to train movement, reduce fuel and electricity costs for train traction, and the operating costs of railway transport for energy consumption. To reduce operating costs using the basic provisions of the locomotive traction theory, calculations were made to determine the energy consumption for the movement of a passenger train according to the profile conditions of the real section of the regional branch of the Southern Railway by diesel and electric locomotive traction with the base variant and the variant of passenger cars with reduced tare weight) in composition of the train. In the calculations, it was considered that for the movement of passenger trains, a diesel locomotive of the TEP70 series is used for diesel traction, and for an AC electric locomotive of the ChS4 series. It has been established that the annual savings in energy costs for the traction of passenger trains when using passenger cars with a reduced tare weight is about 1 million UAH. Keywords: passenger car, body, resource, wear, modernization, economic effect.

СОВЕРШЕНСТВОВАНИЕ МЕТОДИКИ ОЦЕНКИ ВИБРАЦИОННОЙ НАГРУЖЕННОСТИ КУЗОВА ПАССАЖИРСКОГО ВАГОНА

The analysis of domestic and foreign studies in the field of evaluating the dynamic strain of passenger car bodies allowed us to find out that most of the methods are based on the evaluation of the vibration strain. An improved method is proposed to consider to evaluate the vibration strain of the car. As a method for determining the body's structural properties, a mathematical modeling method is proposed. On the basis of this method, a finite element model of the body is developed, which natural frequencies and forms of vibrations are calculated by Lanczos method. The results obtained by finite element model are compared with the data obtained during tests conducted by the Testing Center TIV. The discrepancy between the calculation and the experiment is 11.85%, which indicates the adequacy of the created finite element model. To define the dynamic load of the body the developed finite element model was reduced to four variants, each of which is transformed into a spatial hybrid dynamic model. The results obtained during the calculation are compared with the values of the running tests of the car. The analysis of the data shows that the fourth variant of the finite element model of the passenger car body, which takes into account the real distribution of the mass of the internal equipment elements and the interior has values more approximate to the data obtained during running tests. Based on this, it can be concluded that this option is most suitable for calculating the stiffness characteristics of the passenger car body.

ИССЛЕДОВАНИЕ ПАРАМЕТРОВ ИЗГИБНЫХ КОЛЕБАНИЙ И АНАЛИЗ МЕТОДОВ ИХ ПОДАВЛЕНИЯ В КУЗОВАХ СОВРЕМЕННЫХ ПАССАЖИРСКИХ ВАГОНОВ

The issues of increasing the passenger comfort level during railway transportation are considered. It is found out that the key factors for the comfort level are vertical vibrations of the body, and their intensity directly depends on the body bending stiffness. In turn, the first frequency and form of bending vibrations of the body can be taken as a criterion for evaluating bending stiffness. Design concepts aimed at increasing the comfort level of passengers and reducing the intensity of vibrations of car bodies are considered. Methods are analyzed that give the opportunity to increase the intrinsic frequency of the body bending vibrations by strengthening the metal structure of the body and making changes to the structure of its power frame, as well as by introducing specific inter-car connections. Methods of vibration isolation of the car bodies are reviewed by controlling damping in the car suspension system, as well as by reducing vibrations associated with the imbalance of wheel pairs. The experience of increasing the level of the com-fort due to the introduction of additional damping and the use of dynamic vibration damping systems has been studied. Advantages and disadvantages of the considered technical solutions are identified, as well as the experience of their use in real operation is evaluated. The analysis of the problem under consideration concerning engineering solutions for reducing bending vibrations of passenger car bodies shows the complexity of solving this problem, requiring the use of a set of theoretical and experimental studies, the choice of methods that take into account the features of the car designs and sources of vibration stimulation.

Basic functions of computational and experimental works for the implementation of the parameter management method of bending vibrations of passenger car bodies

Basic functions of computational and experimental works for the implementation of the parameter management method of bending vibrations of passenger car bodies

Effect of carbody flexibility on the dynamic performance of an empty freight wagon

The structural flexibility of passenger car bodies is paid most attention in research due to the effect it has on the passenger ride comfort. But as we are moving towards high speed and lightweight freight Railway stock, the issue of structural flexibility becomes essential in the case of freight wagons also. This paper investigates the effect of including the structural flexibility of the carbody of Indian Railway open freight car BOXNHL in the dynamic analysis. A mid surface meshed model of the subject carbody is developed using Hyperworks. Then, modal analysis is done using MSC FEA to identify the dominant flexible body modes. A simulation study has been conducted using NUCARS (New and Untried Car Analytic Regime Simulation) for an empty freight car on straight track and curve. Four types of carbodies have been considered for comparison- rigid carbody, flexible carbody having modal damping factor 0.04, 0.03, and 0.02. Vertical and lateral accelerations are chosen as the representative dynamic response parameters. The novelty of the present work lies in analyzing the effect of modal damping factors on the different response parameters (vertical and lateral accelerations) of empty BOXNHL freight wagon at different speeds. The field test results have been compared with the simulation results for identifying the modal damping factor with a minimum standard deviation.

Development and evaluation of a complex of studies to increase the frequency of bending vibrations of modern passenger car bodies

Investigations of the frequency of bending vibrations of the car bodies of 61-4440 model range, which includes compartment cars, staff cars, non-compartment cars, coach cars, restaurant cars and others, are described. The bodies of all cars of this model range have the same overall dimensions and are made of corrosionresistant steels (stainless) with flat corrugated sheathing of the lower (under the window) belt.To assess the influence of the design features of stainless steel bodies on its bending stiffness and the parameters of bending vibrations in the vertical plane, a computational and experimental complex of works was carried out.After analyzing the calculation results and experimental data, proposals were developed and implemented to increase the bending stiffness of the metal body structure with stainless steel skin. To check the implemented proposals, complex tests were carried out to determine the parameters of bending vibrations of the metal structure of the experimental body. The tests were carried out according to the combined method developed by the authors. For this, a vibrator, installed in the console parts of the body, and impulse excitation were used.The results of testing the metal structure of the experimental body in comparison with the results of testing the car bodies of 61-4440 model range showed the effectiveness of the implemented proposals, namely: increasing the frequency of the first tone of bending vibrations by 18 %; decrease in the amplitude of vertical vibrations of the body structure at the frequency of the first tone from 12 to 50 %; decrease in the amplitude of the vertical accelerations of the metal structure of the body during oscillations at the frequency of the first tone approximately by 2 times; significant reduction in horizontal acceleration in the area of the middle section walls. The effectiveness of the implemented proposals for increasing the bending stiffness of the metal structure of the experimental body allows recommending them for the entire model range of 61-4440 cars.

A NEW FASTENER TO ENSURE THE RELIABILITY OF A PASSENGER CAR BODY ON A TRAIN FERRY

To ensure the strength of the passenger car bodies during transportation on train ferries, it is proposed to mount fastening elements of chain binders on the body bolster beams. The principle of such an element is based on the hydraulic damper operation. The mathematic modelling was conducted in order to determine the dynamic loading on a passenger car body during sea transportation. The study established that the improvements mentioned made it possible to reduce the dynamic loading on the body during sea transportation by 30% in a comparison with that of a typical fastening scheme. The strength of an improved passenger car body was calculated. The maximum equivalent stresses in the body structure accounted for about 120MPa, i.e., they did not exceed the admissible values. The conducted research may contribute to ensuring the required strength of passenger car bodies during train ferry transportation, thus leading to a higher operational efficiency of train ferry transportation within the international transportation.

Improvements in passenger car body for higher stability of train ferry

The authors suggest that the strength of passenger car bodies under train ferry transportation can be provided by mounting fastening elements of chain binders on the body bolster beams. The principle of such an element is based on the hydraulic damper operation Therefore, the authors developed a mathematical model which considered displacements of a train ferry loaded with passenger cars under rolling motion. The model was solved in Mathcad software. The mathematic modeling was conducted in order to determine the dynamic loading on a passenger car body under sea transportation. The study established that the improvements mentioned made it possible to reduce the dynamic loading on the body under sea transportation by 30% in comparison with that of a typical fastening scheme. The strength of an improved passenger car body was calculated. The maximum equivalent stresses in the body structure accounted for about 120 MPa, i.e., they did not exceed the admissible values. Besides, the study presents the computer modelling of dynamic loads of the carrying structure of a passenger car body under train ferry transportation. Numerical values of the accelerations and their distribution fields relative to the carrying structure of a car were determined. The adequacy of the designed models was checked with an F-test. The research and proposed engineering solutions can ensure the adequate strength of passenger car bodies under their transportation by train ferries, and also conduct efficient international rail/ferry transportation.

Modeling of nonlinear shock deformation of passenger car bodies with emergency exits

Original design solutions for passenger car bodies equipped with emergency exits have been proposed. The operability and safety of the proposed structures is evaluated based on the modeling of the load bearing structures in emergency situations. Two options for the development of an emergency are considered: a collision with a car on a level crossing and rollover. The analysis of loading was performed by the finite element method in a dynamic nonlinear formulation. The finite element models of the supporting structures of the bodies of passenger cars with evacuation exits and without them have been developed. Model verification was performed by field bench tests. The dynamic loading was estimated in a dynamic setting by the explicit integration method based on the central difference method with keeping the accelerations constant within the step and quadratic approximation of the displacement vector for three consecutive moments of time. The data obtained as a result of the study on the stress-strain state of the supporting structure indicate the operability and safety of the proposed solutions. A variant of the body structure of a double-decker car is protected by a patent for a utility model.

ПРОГНОЗИРОВАНИЕ УСТАЛОСТНОЙ ДОЛГОВЕЧНОСТИ НЕСУЩЕЙ КОНСТРУКЦИИ КУЗОВА ПАССАЖИРСКОГО ВАГОНА С ПЕРФОРИРОВАННЫМИ ПОДКРЕПЛЯЮЩИМИ ЭЛЕМЕНТАМИ

The purpose of the work is a fatigue life assessment for bearing structures of passenger car bodies with perforated supporting elements through the methods of computer mathematical modeling. 
 The fulfilled analysis of investigations in the field of the fatigue life assessment for welded bearing structures of car bodies has shown that its assessment should be carried out in a dynamic setting with the development of a spatial dynamic model of a car body. 
 The fatigue life assessment in the most loaded areas of perforated supporting elements in car bodies was carried out with the use of two procedures: Serensen-Kogaev procedure and Bolotin one. There are considered ten versions of supporting element perforation in a passenger car body. The development of finite element models of car bodies with the mentioned options is carried out by the example of the body of a domestic passenger car. On the basis of the design strength computation results there are defined three most loaded areas of perforated supporting elements. The refined assessment of a dynamic stressed state of the areas under investigations is carried out through the method of an area successive accentuation. 
 As a result of the investigation there are obtained life values of the most loaded areas for a passenger car body bearing structure for all perforation options under consideration. 
 The results obtained confirm passenger car operation safety with the offered option of perforation and are evidence of the purposefulness in the application of the procedure offered for the fatigue life prediction of similar bearing structures.

ОБОСНОВАНИЕ КОНСТРУКТИВНЫХ РЕШЕНИЙ НЕСУЩИХ КОНСТРУКЦИЙ КУЗОВОВ ПАССАЖИРСКИХ ВАГОНОВ С ПЕРФОРИРОВАННЫМИ ПОДКРЕПЛЯЮЩИМИ ЭЛЕМЕНТАМИ

As a method of investigations there is adopted a computer mathematical modeling based on the use of a finite element method. The choice of a type and perforation parameters is connected with the problem in the large array creation of bearing structure design models of passenger car bodies. The analysis of investigations carried out in the field of multi-variation computations has shown that the most efficient investigation method is a superelement reduction. Its use allows decreasing labor and time costs for the body design model development at the expense of the initial super-element with the perforation area for a new one. 
 The appraisal of the procedure offered on the choice of a body efficient bearing structure with the perforated profiles is carried out by the example of the body of a domestic passenger car according to the criteria of strength and assurance of the highest weight reduction of a bearing structure. 
 In the first stage of the work there are defined types and parameters of perforation possible for use in the structure. Finite element design models of car bodies are developed. On the basis of strength computation results the reinforcing elements of the structure are offered which have a margin safety for perforation application in them. Based on the analysis of car body bearing structure there is carried out a choice of an efficient unit of a finite element model which will be used as a super-element. In the next stage of the work there are developed and computed structures of car bodies with the perforation types under consideration and with the use of superelements. 
 The computation results have shown that maximum design stresses of car bodies for all perforation types under consideration do not exceed legitimate values. As an efficient bearing structure of a passenger car body there is adopted a car body with the sixth type of perforation ensuring the largest decrease of structure metal intensity and satisfying strength requirements. 
 The procedure developed can be used at designing modern bearing structures of passenger car bodies having improved technical and economic values.

構造物の補剛効果の定量的な予測に関するUstar（U*）の 一般的適用法の開発および急ハンドル時の車体高剛性化への応用

構造物の補剛効果の定量的な予測に関するUstar（U*）の 一般的適用法の開発および急ハンドル時の車体高剛性化への応用

General principles of control method of passenger car bodies bending vibration parameters

Weight reduction of passenger cars is a promising direction of reducing the cost of their production and increasing transportation profitability. One way to reduce the weight of passenger cars is the lightweight metal body design by means of using of high-strength aluminum alloys, low-alloy and stainless steels. However, it has been found that the limit of the lightweight metal body design is not determined by the total mode of deformation, but its flexural rigidity, as the latter influences natural frequencies of body bending vibrations. With the introduction of mandatory certification for compliance with the Customs Union technical regulations, the following index was confirmed: “first natural frequency of body bending vibrations in the vertical plane”. This is due to the fact that vibration, noise and car motion depend on this index. To define the required indexes, the principles of the control method of bending vibration parameters of passenger car bodies are proposed in this paper. This method covers all stages of car design – development of design documentation, manufacturing and testing experimental and pilot models, launching the production. The authors also developed evaluation criteria and the procedure of using the results for introduction of control method of bending vibration parameters of passenger car bodies.

An analysis of the active safety of a passenger car body during car use

Passenger car bodies made nowadays are most often self-bearing constructions. This is the reason why a change in the parameters of a car body during its use also affects other sets of component parts, which are attached to it. While a passenger car is driven, the car body is exposed to various factors which can cause sudden damage or gradual wear of the car’s technical condition. This paper contains an analysis of the influence of changes in the geometry of a car body on changes in the geometry of wheels. The study was carried out on C-segment cars produced by the same manufacturer. While making an assessment of the car body’s geometry, the location of base points on the floor pan and the upper parts of the car bodywork, within the motor chamber, etc. was assayed. All vehicles were constructed on the same floor pan. Measurements were performed with a Gysmeter made by the company Gys and supported by Autorobot Datasheet software, while the geometry of wheels was measured with a computerised laser device Autoboss A-860. Camber, castor and steering axis inclination were some of the wheel geometry parameters measured in our study.