Investigation of Relationship between Train Speed and Bolted Rail Joint Fatigue Life using Finite Element Analysis

2018 ◽  
Vol 2672 (10) ◽  
pp. 85-95 ◽  
Author(s):  
Hao Yin ◽  
Yu Qian ◽  
J. Riley Edwards ◽  
Kaijun Zhu
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Impact Load ◽  
Wheel Load ◽  
Joint Area ◽  
Train Speed ◽  
Stress Propagation ◽  
Speed Restrictions ◽  
The Impact ◽  
The Relationship

Reducing the allowable operating speed or imposing temporary speed restrictions are common practices to prevent further damage to rail track when defects are detected related to certain track components. However, the speeds chosen for restricted operation are typically based on past experience without considering the magnitude of the impact load around the rail joints. Due to the discontinuity of geometry and track stiffness at the bolted rail joints, an impact load always exists. Thus, slower speeds may not necessarily reduce the stresses at the critical locations around the rail joint area to a safe level. Previously, the relationship between speed and the impact load around the rail joints has not been thoroughly investigated. Recent research performed at the University of Illinois at Urbana-Champaign (UIUC) has focused on investigating the rail response to load at the joint area. A finite element model (FEM) with the capability of simulating a moving wheel load has been developed to better understand the stress propagation at the joint area under different loading scenarios and track structures. This study investigated the relationship between train speed and impact load and corresponding stress propagation around the rail joints to better understand the effectiveness of speed restrictions for bolted joint track. Preliminary results from this study indicate that the contact force at the wheel–rail interface would not change monotonically with the changing train speed. In other words, when train speed is reduced, the maximum contact force at the wheel–rail interface may not necessarily reduce commensurately.

Dynamic Ultimate Strength Characteristics of Stiffened Plates Subjected to the In-Plane Impact Load and Lateral Pressure

2021 ◽  
Author(s):  
Qiang Zhong ◽  
De-yu Wang
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Lateral Pressure ◽  
Impact Load ◽  
Strength Characteristics ◽  
Stiffened Plates ◽  
Strength Theory ◽  
Explicit Finite Element ◽  
Static Conditions ◽  
The Impact

Abstract Dynamic capacity is totally different from quasi-static capacity of ship structural components, although most ultimate strength analyses at present by researchers are performed under quasi-static conditions. To investigate the dynamic ultimate strength characteristics, the dynamic ultimate strength analyses of stiffened plates subjected to impact load were studied based on a 3-D nonlinear explicit finite element method (FEM) in this paper. The impact load in the present work is characterized as a half-sine function. A series of nonlinear finite element analyses are carried out using Budiansky-Roth (B-R) criterion. The influence of impact durations, model ranges, boundary conditions, initial imperfections and impact loads on the dynamic ultimate strength of stiffened plates are discussed. In addition, the ultimate strength of stiffened plates under the in-plane impact combined with lateral pressure was also calculated, which shows lateral pressure has a negligible effect on the dynamic ultimate strength of stiffened plates subjected to the impact load with short durations. Other important conclusions can be obtained from this paper, which are useful insights for the development of ultimate strength theory of ship structures and lay a good foundation for the study of dynamic ultimate strength in the future.

Microstructure and Impact Load Performance of Friction Stir Welded Joint of AZ31B Magnesium Alloy

2020 ◽  
Vol 866 ◽  
pp. 54-62
Author(s):  
Hong Feng Wang ◽  
Sheng Rong Liu ◽  
Xiao Le Ge ◽  
Jia Fei Pu ◽  
Lei Bao ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Impact Load ◽  
Base Material ◽  
Welding Parameters ◽  
Loading Test ◽  
Az31b Magnesium Alloy ◽  
Friction Stir ◽  
Joint Area ◽  
The Impact

10mm thickness AZ31B magnesium alloy was used as the friction stir welding object in this study. Different welding joints were obtained by setting different friction stir welding parameters. Metallographic analysis and impact loading test were carried out on the joint area. The experiment results show that (i) when the rotational speed of the stirring head is 600rpm and the welding speed is 120mm/min, the microstructure of the joint has the characteristics of compactness, thinning, and large-area twinning, which is beneficial to improve the plasticity of the joint area; (ii) the impact load of the joint is the highest, but lower than that of the base material, which is 95.5% of the base material; (iii) the fracture of impact specimen presents ductile fracture.

scholarly journals Finite Element Analysis of Impact Energy on Spur Gear

2018 ◽  
Vol 225 ◽  
pp. 06011 ◽  
Author(s):  
Ismail Ali Bin Abdul Aziz ◽  
Daing Mohamad Nafiz Bin Daing Idris ◽  
Mohd Hasnun Arif Bin Hassan ◽  
Mohamad Firdaus Bin Basrawi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Energy ◽  
High Speed ◽  
Impact Test ◽  
Impact Load ◽  
Gear Tooth ◽  
Test Equipment ◽  
Element Analysis ◽  
The Impact

In high-speed gear drive and power transmission, system impact failure mode always occurs due to the sudden impact and shock loading during the system in running. Therefore, study on the amount of impact energy that can be absorbed by a gear is vital. Impact test equipment has been designed and modelled for the purpose to study the impact energy on gear tooth. This paper mainly focused on Finite Element Analysis (FEA) of impact energy that occurred during simulation involving the impact test equipment modelling. The simulation was conducted using Abaqus software on critical parts of the test equipment to simulate the impact event and generate impact data for analysis. The load cell in the model was assumed to be free fall at a certain height which gives impact load to the test gear. Three different type of material for the test gear were set up in this simulation. Results from the simulation show that each material possesses different impact energy characteristic. Impact energy values increased along with the height of load drop. AISI 1040 were found to be the toughest material at 3.0m drop that could withstand up to 44.87N.m of impact energy. These data will be used to validate data in physical experiments in further study.

Finite Element Analysis of a Single-Layer Reticulated Dome under Impact Loading

2010 ◽  
Vol 163-167 ◽  
pp. 327-331 ◽  
Author(s):  
Liang Zheng ◽  
Zhi Hua Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Impact Force ◽  
Impact Load ◽  
Residual Deformation ◽  
Time History ◽  
Single Layer ◽  
Element Analysis ◽  
Deformation Stage ◽  
The Impact

Finite element model of both the single-layer Schwedler reticulated dome with the span of 50m and a Cuboid impactor were developed, incorporating ANSYS/LS-DYNA. PLASTIC_KINEMATIC (MAT_003) material model which takes stain rate into account was used to simulate steel under impact load. The automatic point to surface contact (NODES TO SURFACE) was applied between the dome and impact block. Three stages of time history curve of the impact force on the apex of the single-layer Scheduler reticulated dome including the impact stage, stable stalemate stage, the decaying stage were generalized according to its dynamic response. It must be pointed out that the peak of the impact force of the single-layer reticulated dome increase with the increase of the weight and the velocity of the impact block, but the change of the velocity of the impact block is more sensitive than the change of weight of the impact block for the effect of the peak of the impact force, and a platform value of the impact force of the single-layer reticulated dome change near a certain value, and the duration time of the impact gradually increase. Then four stages of time history curve of the impact displacement were proposed according to the dynamic response of impact on the apex of the single-layer reticulated dome based on numerical analysis. Four stages include in elastic deformation stage, plastic deformation stage, elastic rebound stage, free vibration stage in the position of the residual deformation.

THE EFFECT OF SHEAR REINFORCEMENT RATIO ON PRESTRESSED CONCRETE BEAMS SUBJECTED TO IMPACT LOAD

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohamad Elani ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Youmn Al Rawi
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Impact Load ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Shear Reinforcement ◽  
Dynamic Increase Factor ◽  
Concrete Damage ◽  
Different Response ◽  
The Impact

Structural elements subjected to impact loads have a different response than those subjected to static loads. This research studied the effect of using shear reinforcement to reduce the local damage occurred when an impact load applied on a prestressed concrete beam. An accurate finite element model was provided for the analysis using the advanced volumetric finite element modeling program (ABAQUS). The concrete material was defined using the built in concrete damage plasticity model (CDP), that considers the nonlinear behavior of concrete when subjected to dynamic loading. All material properties were modified using the dynamic increase factor (DIF) to consider the effect of impact loading. It was realized that the failure was concentrated in the impact zone. However, using shear reinforcement reduced the permanent damage occurred due to impact.

Wheel/rail impacts at a railway turnout crossing

1998 ◽  
Vol 212 (2) ◽  
pp. 123-134 ◽  
Author(s):  
C Andersson ◽  
T Dahlberg
Keyword(s):  
Contact Force ◽  
Discrete Systems ◽  
Element Model ◽  
Beam Elements ◽  
Modal Damping ◽  
Moving Vehicles ◽  
Static Contact ◽  
Train Speed ◽  
The Impact ◽  
Railway Turnout

The vertical dynamics of a common Swedish railway turnout under the load of moving vehicles is investigated. The turnout is described by a linear finite element model with modal damping. The model of the turnout (a section of it) has a length of 36 sleeper spans surrounding the crossing. Rails and sleepers are modelled with uniform Rayleigh-Timoshenko beam elements. The rails are connected via railpads (linear springs) to the sleepers, which rest on an elastic foundation. The vehicles which model the dynamic behaviour of trains are discrete systems of masses, springs and dampers. They pass the turnout on the through rails at a constant speed and only vertical dynamics (including roll and pitch motions) is studied. The wheel/rail contact is modelled by use of a non-linear Hertzian spring. The train/track interaction problem is solved numerically by using an extended state space vector approach in conjunction with modal superposition for the turnout. The analyses show that the rail discontinuity at the crossing leads to an increase in the wheel/rail contact force. Both smooth and irregular transitions of the wheels from the wing rail to the crossing nose have been examined for varying speeds of the vehicle. Under perfect conditions, the wheels will change quite smoothly from rolling on the wing rail to rolling on the nose. The impact at the crossing will then be small, giving a maximum wheel/rail contact force which is only 30-50 per cent larger than the static contact force. For uneven transitions, the severity of the impact loading at the crossing depends strongly on the train speed. The increase in the contact force, as compared with the static force, is of the order of 100 per cent at 70 km/h and 200 per cent at 150 km/h.

The Analysis on Suspension of Fire Robot Based on FEA

2014 ◽  
Vol 716-717 ◽  
pp. 1536-1539
Author(s):  
Yan Xu ◽  
Shu Fang ◽  
Jian Qiao Fu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stress Condition ◽  
Impact Load ◽  
Element Model ◽  
Force Condition ◽  
Environmental Adaptability ◽  
The Impact ◽  
Suspension Structure

The suspension of fire robot, one of necessary components, directly impacts the environmental adaptability, and the strength of suspension has great importance to the life of robot. In the paper, the structure and the stress condition of the suspension was analyzed. The force condition of suspension is simplified as a 2-D diagram, the load acting on the elbow were simplified in two direction, A finite element model, which simulated the impact load and optimized the design of suspension, was established, and the result of the simulation shows the suspension structure is reasonable and the strength of the component is enough.

scholarly journals Collapse Behaviour of a Concrete-Filled Steel Tubular Column Steel Beam Frame under Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lian Song ◽  
Hao Hu ◽  
Jian He ◽  
Xu Chen ◽  
Xi Tu
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Mechanical Performance ◽  
Impact Load ◽  
Frame Structure ◽  
Actual Condition ◽  
Transverse Impact ◽  
Time Curve ◽  
Finite Element Software ◽  
The Impact

The progressive collapse of a concrete-filled steel tubular (CFST) frame structure is studied subjected to impact loading of vehicle by the finite-element software ABAQUS, in the direct simulation method (DS) and alternate path method (AP), respectively. Firstly, a total of 14 reference specimens including 8 hollow steel tubes and 6 CFST specimens were numerically simulated under transverse impact loading for verification of finite-element models, which were compared with the existing test results, confirming the overall similarity between them. Secondly, a finite-element analysis (FEA) model is established to predict the impact behaviour of a five-storey and three-span composite frame which was composed of CFST columns and steel beams under impact vehicle loading. The failure mode, internal force-time curve, displacement-time curve, and mechanical performance of the CFST frame were obtained through analyzing. Finally, it is concluded that the result by the DS method is closer to the actual condition and the collapse process of the structure under impact load can be relatively accurately described; however, the AP method is not.

scholarly journals Blasting Impact Simulation Test and Fragmentation Distribution Characteristics in an Open-Pit Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohua Ding ◽  
Xiang Lu ◽  
Wei Zhou ◽  
Xuyang Shi ◽  
Boyu Luan ◽  
...  
Keyword(s):  
Coal Mine ◽  
Wave Attenuation ◽  
Split Hopkinson Pressure Bar ◽  
Impact Load ◽  
Large Diameter ◽  
Test System ◽  
Open Pit ◽  
Hopkinson Pressure Bar ◽  
The Impact ◽  
The Relationship

Based on the split Hopkinson pressure bar (SHPB) test system, dynamic impact tests of coal specimens under different impact pressures were carried out to study the relationship between the impact load and the size of crushed lump coal. Based on the theory of stress wave attenuation, the relationship between the blasting impact load in a single-hole blasting area of a coal seam and the load applied in an impact failure test of a coal specimen in the laboratory was established. According to the characteristics of the fragmentation distribution of the coal specimens destroyed under a laboratory impact load and the requirement of the minimum cost control of coal blasting in an open-pit coal mine, the fragmentation size range was divided into three groups: large-diameter, medium-diameter, and powder particles. Based on this range, the variation rule of the mass percentage of coal fragments with impact pressure was obtained. Established on the evaluation principle of the blasting effect in an open-pit coal mine, a good impact fragmentation effect was obtained. The good pressure range is 0.30 MPa≤P<0.90 MPa.

Finite Element Stress Response Analysis of Stepped-Lap Adhesive Joints Subjected to Impact Tensile Load

2000 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Takahiro Ohmori
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Principal Stress ◽  
Impact Load ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Maximum Value ◽  
Adhesive Thickness ◽  
The Impact

Abstract The stress wave propagation and the stress distribution in stepped-lap adhesive joints of similar adherends subjected to impact tensile loads and elastic deformation are analyzed using three-dimensional finite-element method (FEM). The impact load is applied to the joint by dropping a weight. One end of the upper adherend is fixed, and the other end of the lower adherend is subjected to an impact load. FEM code employed is DYNA3D. The effects of Young’s modulus of the adherends, the number of lapped steps, and the adhesive thickness on the stress wave propagation at the lapped, and fee butted interfaces are examined. It is also found that the maximum value of the maximum principal stress σ1 occurs at the end of the butted interface between the adhesive and the lower adherend to which the impact load is applied. As the number of the lapped steps increases, the maximum value of the maximum principal stress σ1 increases. It is found that the maximum value of the maximum principal stress σ1 increases as the adhesive thickness decreases. The maximum value of σ1 increases as Young’s modulus of the adherends increases. In addition, the experiments were carried out to measure the strain response of stepped-lap adhesive joints subjected to impact tensile loads using strain gauges. A fairly good agreement is seen between the analytical, and the experimental results.

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