Multi-body Dynamics Simulation Software Research Articles

Dynamic Response Analysis of Moving Trains Passing Through the Stationary Thunderstorm Downburst Wind

The safety of the high-speed train traveling through the stationary thunderstorm downburst wind was studied. First, a thunderstorm wind test device was used to simulate the stationary thunderstorm downburst wind. Based on the rigid model pressure measurement tests, the aerodynamic forces of the train traveling along different paths through the stationary thunderstorm downburst wind were measured. The influence of the radial distance of the crossing path on the aerodynamic force coefficients of the train was investigated. On this basis, an unsteady aerodynamic model of the high-speed train crossing through the stationary thunderstorm downburst wind was established, and dynamic response analysis was carried out using the SIMPACK multibody dynamics simulation software to explore further the safety of the high-speed train crossing through the stationary thunderstorm downburst wind. The research showed that the stationary thunderstorm downburst wind field has significant spatial variation characteristics compared with the atmospheric boundary layer wind field. When the train passes through the thunderstorm downburst wind, the radial wind speed and wind yaw angle experienced by the train constantly change, and the change curve shows a symmetrical distribution. The aerodynamic force of the train will undergo sudden loading and unloading processes, and the lateral force coefficient of the train on different paths shows a “pulse-type” variation. Moreover, the lateral force coefficient increases with the increase of wind yaw angle. Under the influence of the thunderstorm downburst wind, the variation trend of the aerodynamic force coefficients of the train is consistent with that under crosswind. However, there are significant differences in the numerical values. Therefore, it is impossible to simply use the formula for calculating the aerodynamic force coefficients of the train under crosswinds to predict the aerodynamic force coefficients of the train under the thunderstorm downburst wind. While passing through the thunderstorm downburst wind, the overturning coefficient index plays a decisive role in the safety of train operations. Train rollover is the main form of train safety accidents, while derailment accidents are not easy. The numerical results obtained in this study are significant for evaluating the operational safety while moving trains traversing the stationary thunderstorm downburst wind.

Design method for suspension parameters of high-speed railway vehicles considering uncertainties

A design method for suspension parameters is proposed to ensure the desired performance of a railway vehicle despite uncertainties. The method used in this study consists of two loops: a sub-loop, which uses parameter uncertainties to determine the minimum value of target performance, and a main loop, which optimises suspension parameters such that the minimal performance achieves Pareto optimality. Thus, by selecting a suitable Pareto solution that ensures the minimum performance is equal to or higher than the required performance, the robustness of the designed vehicle against the parameter uncertainties can be achieved. The lowest low-frequency damping ratio in the service speed range was selected as one of the design targets. The other target was the critical speed. Two wheel-rail contact characteristics were applied, considering the worst conditions for each design target. The distribution of the parameter uncertainties that minimised the vehicle performance showed distinct characteristics between the longitudinal and lateral suspension parameters, which provides useful information for the maintenance of railway vehicles. The performance analysis for 100,000 random samples shows that the vehicle performed better than the targets with a high probability despite the parameter uncertainties. Further, the simulation results using multi-body dynamics simulation software validated the viability of the proposed method.

High-Speed Train Running Characteristics Assessments Using Multibody Dynamics Simulation

The development of railway transportation in Indonesia in recent years has increased the number of new vehicles with various types and specifications. These new vehicles should pass a series of running characteristics assessments against standards to ensure safety and comfort in operation. Before the field testing, the assessments using numerical simulation in the design stage need to be done. This study aims to assess the high-speed train running characteristics through modeling and testing using multibody dynamics simulation software. The standards used for the assessments refer to EN 14363 – Testing and Simulation for The Acceptance of Running Characteristics of Railway Vehicles. The high-speed train model was built and validated through four methods with comparative values calculated analytically. The validated model was then run in the simulation to get the parameters for assessment. The parameters include the coefficient of flexibility, critical speed, safety against derailment with various methods, ride comfort, and vibration mode. The parameters obtained from the simulation are compared to the acceptance criteria specified in the standard. The results show that the vehicle performance fulfills the requirement prescribed by EN 14363 standard. After the vehicle and the track infrastructure are ready, they need to be confirmed by a series of testing performed on the main line. This study supports the development of high-speed trains in Indonesia and is expected to give more insight into the usefulness of numerical simulation to predict the characteristic of dynamic performances of railway vehicles in actual operating conditions.

Study on the bearing characteristics of overrun hydraulic support under impact loading

In order to study the effects of stress change and adaptability of the overrun hydraulic stent under impact load, the rigid–flexible coupling numerical model of the stent is established using multi-body dynamics simulation software ADAMS. In the model, the stent is flexibilized using the HyperMesh module, and the column and jack are equivalently replaced with a spring damping system. By applying impact loads to different positions above the front roof beam of the stent, the dynamic response characteristics of the column and the articulation point are obtained at different positions with different strengths. The results show that when the impact load is applied to different positions of the front roof beam, the steady-state response force of the column shows an overall “M" distribution, and along the length direction of the roof beam, the steady-state response force of the column shows an upward trend, and the maximum steady-state response force of the column is 547 kN at point (1, 6); when the impact load is applied to both sides of the front roof beam, the response at the articulation point is greater, resulting in a higher maximum simple harmonic response at that articulation point. When the impact load acts on both sides of the front roof beam, the response of the articulation point is greater, with a maximum simple harmonic response coefficient of 0.75 and a maximum excitation response coefficient of 0.28; when the impact loads of different strengths act on the whole front roof beam, the force acting on the column and pin shaft at the articulation point will produce a large impact, reducing its adaptability. To address this, we can consider changing the top plate stress conditions using methods like high-pressure injection of water and control the gradual and slow release of the top plate stresses. The results of the study provide a reference for the structural strength design and reliability analysis of the hydraulic support, which is of practical significance and value for improving the safe mining of the coal mining face.

Stress Simulation on Four-Bar Link-Type Transplanting Device of Semiautomatic Vegetable Transplanter

The aim of this study is to analyze the stress exerted on a four-bar link-type transplanting device using two distinct methods: stress measurement performed during a field test and stress simulation. A field test is conducted to measure stress using a strain gauge positioned at 15 specific points on the transplanting device. Subsequently, the measured strain data are converted into calculated stress data. In another method, stress is simulated using specialized multibody dynamic simulation software. The simulation results are compared with the stress measured during field tests to verify the simulation model. Based on the results, the maximum stress derived from the simulation correlates with the measured results, although notable discrepancies are shown, particularly at strain gauge positions 11 and 13. The maximum stress derived from the simulation is used to calculate the static safety factor of the transplanting device. The peak stress derived from the simulation aligns with the measured results, although significant discrepancies are observed at positions corresponding to strain gauges 4 and 10. The maximum stress (150.82 MPa) is observed on the link of the transplanting device, and the static safety factor determined via the simulation is 1.39.

Backstepping model‐free adaptive control for a class of second‐order nonlinear systems

SummaryThis paper proposes a backstepping model‐free adaptive control (BS‐MFAC) algorithm for the trajectory tracking control problem of a class of second‐order nonlinear systems. Firstly, the model‐free adaptive control (MFAC) is employed to track the virtual desired velocity. Then, based on the measured state data at the current moment, a virtual desired velocity is designed, combining MFAC with backstepping control in a clever manner. By designing a discrete form of Lyapunov function, it is proven that the system velocity error under this algorithm converges asymptotically and stably. Furthermore, a nonhomogeneous difference equation solution related to the system position is obtained through calculations. The analysis of the solution indicates that the system position output error will slide into a neighborhood around zero. This algorithm possesses advantages such as simple structure, model independence, and strong robustness. Additionally, a planar two‐link space robot arm model is constructed using the Mbdyn platform, a multibody dynamics simulation software. Trajectory tracking control of joint angles is achieved under the proposed control algorithm in this paper. The simulation outcomes unequivocally establish the efficacy of the algorithm, which adeptly exploits the pseudo partial derivatives (PPD) estimation for second‐order nonlinear systems in MFAC. The algorithm yields expedited and superior trajectory tracking control of said systems.

Vibration Reduction of Robot End Effector Based on Co-simulation Method

Hydraulic cylinder replacement robot as a new type of engineering machinery has been increasingly used, but its end effector encounters vibrations in the process of clamping the object, so the accuracy of disassembling and assembling the cylinder will be reduced, thus reducing the replacement efficiency and affecting the user’s experience. To address this problem, virtual prototyping technology is used to study the cylinder disassembly process under real working conditions. We use the 3D modeling software Solidworks to construct a model of the cylinder replacement robot. After that, kinematic analysis of the model is carried out, then a dynamics model is built in multi-body dynamics simulation software ADAMS to simulate the process of the robot grasping the object, as a consequence, the trajectory of the end effector is calculated. A controlled dynamic model is established with Simulink and Adams by using the co-simulation technique, and optimization is carried out by using the model. Results show that the optimized control parameter can effectively reduce the end effector vibration and improve the stability and accuracy of the work.

LuGre or not LuGre

The LuGre model is widely used in the analysis and control of systems with friction. Recently, it has even been made available in the commercial multibody dynamics simulation software system Adams. However, the LuGre model exhibits well-known drawbacks like too low and force rate-dependent break-away forces, drift problems during sticking periods, and significant differences in non-stationary situations between the pre-defined friction law and the one produced by the LuGre model. In the present literature, these problems are supposed to come from the model dynamics or its nonlinear nature. However, most of these drawbacks are not simple side effects of a dynamic friction model but are caused in the LuGre approach, as shown here, by a too simple and inconsistent model of the bristle dynamics. Standard examples and a more practical application demonstrate that the LuGre model is not a “what you see is what you get” approach. A dynamic friction model with accurate bristle dynamics and consistent friction force is set up here. It provides insight into the physical basis of the LuGre model dynamics. However, it results in a nonlinear and implicit differential equation, whose solution will not be easy because of the ambiguity of the friction characteristics. The standard workaround, a static model based on simple regularized characteristics, produces reliable and generally satisfactory results but definitely cannot maintain a stick. The paper presents a second-order dynamic friction model, which may serve as an alternative. It can maintain a stick and produces realistic and reliable results.

CALIBRATION OF HOLZAPFEL-GASSER-OGDEN COLLATERAL LIGAMENT PROPERTIES IN A HYBRID POST-ARTHROPLASTY KNEE JOINT MODEL FOR LAXITY TESTING

This study aims to create a novel computational workflow for frontal plane laxity evaluation which combines a rigid body knee joint model with a non-linear implicit finite-element model wherein collateral ligaments are anisotropically modelled using subject-specific, experimentally calibrated Holzpfel-Gasser-Ogden (HGO) models.The framework was developed based on CT and MRI data of three cadaveric post-TKA knees. Bones were segmented from CT-scans and modelled as rigid bodies in a multibody dynamics simulation software (MSC Adams/view, MSC Software, USA). Medial collateral and lateral collateral ligaments were segmented based on MRI-scans and are modelled as finite elements using the HGO model in Abaqus (Simulia, USA). All specimens were submitted varus/valgus loading (0-10Nm) while being rigidly fixed on a testing bench to prevent knee flexion. In subsequent computer simulations of the experimental testing, rigid bodies kinematics and the associated soft-tissue force response were computed at each time step. Ligament properties were optimised using a gradient descent approach by minimising the error between the experimental and simulation-based kinematic response to the applied varus/valgus loads. For comparison, a second model was defined wherein collateral ligaments were modelled as nonlinear no-compression spring elements using the Blankevoort formulation.Models with subject-specific, experimentally calibrated HGO representations of the collateral ligaments demonstrated smaller root mean square errors in terms of kinematics (0.7900° +/− 0.4081°) than models integrating a Blankevoort representation (1.4704° +/− 0.8007°).A novel computational workflow integrating subject-specific, experimentally calibrated HGO predicted post-TKA frontal-plane knee joint laxity with clinically applicable accuracy. Generally, errors in terms of tibial rotation were higher and might be further reduced by increasing the interaction nodes between the rigid body model and the finite element software. Future work should investigate the accuracy of resulting models for simulating unseen activities of daily living.

Anomaly Detection Method in Railway Using Signal Processing and Deep Learning

In this paper, anomaly detection of wheel flats based on signal processing and deep learning techniques is analyzed. Wheel flats mostly affect running stability and ride comfort. Currently, domestic railway companies visually inspect wheel flats one by one with their eyes after railway vehicles enter the railway depots for maintenance. Therefore, CBM (Condition-Based Maintenance) is required for wheel flats resolution. Anomaly detection for wheel flat signals of railway vehicles using Order analysis and STFT (Short Time Fourier Transform) is studied in this paper. In the case of railway vehicles, it is not easy to obtain actual failure data through running vehicles in a university laboratory due to safety and cost issues. Therefore, vibration-induced acceleration was obtained using a multibody dynamics simulation software, SIMPACK. This method is also proved in the other paper by rig tests. In addition, since the noise signal was not included in the simulated vibration, the noise signal obtained from the Seoul Metro Subway Line 7 vehicle was overlapped with the simulated one. Finally, to improve the performance of both detection rate and real-time of characteristics based on existing LeNet-5 architectures, spectrogram images transformed from time domain data were proceeded with the LeNet deep learning model modified with the pooling method and activation function. As a result, it is validated that the method using the spectrogram with a deep learning approach yields higher accuracy than the time domain data.

A comparison of main bearings load of two-cylinder “V” and boxer motorcycle engines

The paper deals with determining the load of the crankshaft main bearings in two-cylinder motorcycle engines. Two cylinder arrangements, used in two-cylinder motorcycle engines, are considered - the boxer-engine and V-engine. The aim of the research is to determine the influence of cylinder arrangement on the magnitude and circumferential distribution of the bearing load of the engines considered. For this purpose, models of a two-cylinder boxer engine and a corresponding V-engine crankshaft drives were developed using multibody dynamics simulation software. Previously, by using a one-dimensional gas analysis software the engine cycles were simulated in order to determine the cylinder pressure required to simulate piston dynamics. As a result of the dynamics simulations, bearing load diagrams of the boxer- and V-engine were obtained, which were then compared and analyzed.

Phase plane analysis applied to non-explicit multibody vehicle models

A new methodology for constructing stability maps (phase-plane analysis) is presented and validated for application to complex multibody vehicle models implemented in Multibody Dynamics simulation software (Adams®). Traditional methodologies are developed to be applied to explicit mathematical models. Given the complexity of some special multibody systems, particularly in vehicle dynamics, simplifications are needed to apply this stability analysis technique. The main limitation when using simplified models is the need to neglect components which could have a significant influence on the dynamic behavior of the system and therefore on its stability. In the proposed methodology it is not necessary to have access to explicit mathematical models of multibody systems. Thus, the stability map of a vehicle model can be constructed by considering highly nonlinear dynamic elements, such as tires and silent-blocks components, modeled using the nonlinear finite element technique.

Dynamic Analyses of Whitworth Quick Return Mechanism

Herein, we present a dynamic analysis on a Whitworth quick return mechanism, which was proposed as a class project to engage Mechanical Engineering students in the Machine Dynamics course. The objectives of the project are to teach (1) kinematic analysis on planar linkage mechanism using complex numbers and (2) kinetic analyses using distributed and lumped mass models. The analytical models were implemented using an engineering math software – Mathcad, and the results were validated by a multibody dynamics simulation software – Inventor. Loop closure equations were first built and solved to find link positions, and then velocities and accelerations were confirmed with numerical differentiation in Mathcad. Based on the solved kinematic quantities, a kinetic analysis was carried out using distributed and lumped mass models as well as in Inventor. The reactions and torques at the input link of the distributed mass model were found identical to those derived from Inventor. It was found the maximum reactions at pin joints were 11% to 100% different between the distributed mass model and the simplified lumped mass model. However, the shaking forces found in both models were nearly identical, and the peak values of the shaking moments were comparable. It is confirmed the lumped mass model can serve as a quick method to find the magnitude of the shaking forces and moments without solving simultaneous equation systems.

Speed-made-good: Mobility map generation for wheeled vehicles on soft terrain

The Nepean Wheeled Vehicle Performance Model (NWVPM) software has been in use for decades as a tool for engineers in industry and governmental agencies to predict the performance of off-road wheeled vehicles. It is based on the Bekker-Wong wheel-terrain interaction model which takes into account both the normal pressure and shear stress distributions at the wheel-terrain interface and uses the Bekker-Wong terrain parameters to characterize the terrain behavior. Using terrain and vehicle parameters as inputs, NWVPM computes various traction indicators such as drawbar pull, tractive effort, sinkage, and external motion resistance as functions of wheel slip by solving a set of equilibrium equations. This paper describes a novel method for predicting vehicle speed-made-good mobility maps and fuel consumption through an analytical approach using NWVPM. To evaluate the proposed method for predicting speed-made-good, a comparison is made with predictions obtained using Vortex, a commercial multibody dynamic simulation software that performs dynamic simulations of vehicles on soft terrain. In addition, a comparison of the capabilities of NWVPM and Vortex in predicting off-road vehicle performance over a range of terrains is presented and the results of the drawbar pull traction test from both software are compared with experimental data.

Design and development of 5-axis robot

Robotics has been developed to ease the works of human beings using assistive robots and robotic arms. This paper is provided with the design and development of such robotic arm. Since the robotic arm is an analogy of human arm, it consists of several rigid links connected and articulated using rotational joints. In this paper, the design and analysis of a simple 5-axis industrial robotic arm is brought forth. The foremost information on the actuators and other electrical components used in this robotic arm is presented. The angular velocity, angular acceleration, and torque at different joints have been calculated and analyzed with the help of the multibody dynamics simulation software ADAMS (Automated Dynamic Analysis of Mechanical Systems). This simulation assisted in determining the stability of the robot and in choosing the appropriate actuators.

Multi-Objective Optimisation of the Electric Wheelchair Ride Comfort and Road Holding Based on Jourdain’s Principle Model and Genetic Algorithm

Abstract The paper addresses the multi-body modelling of an electric wheelchair using Jourdain’s principle. First, a description of the adopted approach was presented. Next, the mathematical equations were developed to obtain the dynamic behaviour of the concerned system. The numerical computation was performed with MATLAB (matrix laboratory: a high performance language of technical computing) and validated by MBD (Multi-Body Dynamics) for Ansys, a professional multi-body dynamics simulation software powered by RecurDyn. Afterwards, the model was treated as an objective function included in genetic algorithm. The goal was to improve the ride quality and the road holding as well as the suspension workspace. The multi-objective optimisation aimed to reduce the Root-Mean-Square (RMS) of the seat’s vertical acceleration, the wheels load and the workspace modulus by varying the bodies’ masses, the spring-damper coefficients and the characteristics of the tires. Acceptable solutions were captured on the Pareto fronts, in contrast to the relatively considerable processing time involved in the use of a random road profile generated by the power spectral density (PSD). During the process, the compatibility and the efficiency of Jourdain’s equations were inspected.

Mechanical structure design and analysis of the outside needle pipe climbing robot

This study designed a crawling mechanism that can solve the measurement problems of slender and needle pipes by detecting the heating vertical needle pipe, which is greatly applied in the petrochemical and refinery industry. The robot’s walking system uses a single driven wheel to stick on the way, with a scissor-hand structure to adapt to changes in diameter between 50 and 90 mm. This study lists the dynamic analysis equation of the robot, thereby obtaining the optimum range of Angle α between the horizontal line and the center line of the main driving wheel and the main clamping wheel. Moreover, the study uses multi-body dynamics simulation software for dynamics simulation analysis. Results indicate that the crawling system has the advantages of anti-deviation, can adapt to different pipe diameters and has a simple structure.

Influence of viscoelastic property of compliance material in achieving successful robotic Peg-In-Hole

Automation of assembly tasks is an inevitable requirement in the manufacturing industries due to the complex design of the components and the requirement for shorter assembly time. In a real-world assembly environment, the misalignments between the mating parts and the necessity for faster insertion due to the time constraints lead to large reactive forces during the insertion. These reactive forces in turn lead to the failure of the insertion process. The successful insertion depends on the handling of these reactive forces using, Remote Centre Compliance (RCC) devices. The selection of the appropriate RCC devices depends on the estimation of stiffness coefficient and damping factors from the dynamic modelling of the assembly process. In order to select the appropriate compliance device and to improve the success rate of the assembly process, this article analyses the contact forces during the dynamic insertion of a single peg component into a hole component, through simulation of the 3-DOF planar robot-aided compliant peg-in-hole assembly process. Rather than considering only the elastic behaviour modelling of compliant devices, this work includes the viscoelastic property of the compliant material in the assembly modelling. An interactive simulation is carried out using the multibody dynamics simulation software MSC Adams/View and MATLAB which is used to precisely compute the contact forces during the insertion phase of the assembly. The results enable one to choose optimal values for lateral and angular stiffness and damping coefficient for a compliant device to achieve a successful assembly task.

The torsional vibration simulation of the diesel engine crankshaft system based on multi-body dynamic model

In order to analyze the torsional vibration of the crankshaft system, a three-dimensional model of the crankshaft system is established, consisted of the piston, connected rod, crank shaft, flywheel and silicone oil damper. Use by multi-body dynamics simulation software ADAMS, created the multi-body dynamics model of the multiple degrees of freedom consisting of rigid hybrid engine system, to do the torsional vibration response simulation, analysis of the torsional vibration on the crankshaft. Through the torsional vibration test of the diesel engine crankshaft system, the accuracy of the simulation calculation results have been verified. This simulation result has higher accuracy, and this calculation method has certain engineering application value.

Fatigue Simulation of Railway Car Bogie Frame Based on Multi-body Dynamics and Finite Element Analysis

This paper proposes to combine multi-body dynamics and finite element method to study the fatigue strength and fatigue life of the bogie frame from the perspective of taking the vehicle as a whole. The analysis model established by the multi-body dynamics simulation software SIMPACK, the dangerous positions are determined from FEA software ANSYS, Based on the load-time history and Miner cumulative damage theory, the fatigue strength prediction is carried out using n-soft software, the study shows that the time-load history of each key position obtained by simulating working conditions can predict the life of components more accurately, this method can be applied to the initial stage of product design.