Quarter Model Research Articles

Crack propagation during Vickers indentation of zirconia ceramics

A quarter finite element model of 3 mol% yttria stabilized tetragonal zirconia polycrystal (3Y-TZP) ceramics undergoing Vickers indentation was established to simulate the evolution of stress and the propagation of cracks inside a sample. The indentation experiment was carried out on the Micro Vickers Hardness Tester. The results of the geometric characteristic parameters, such as the indentation diagonal half-length a, the crack length c and the maximum indent depth hm, from the indentation simulation and experiment were similar. The types of indentation cracks under various loads were determined according to the Lawn-Evan model, which exactly correspond to the simulation results. In addition, the propagation of indentation cracks was discussed based on the maximum principal stress contour plots at various stages, and the conclusions were verified by the indentation analysis model proposed by Yoffe. As a result, the model developed in this paper can be used in indentation studies to solve the related problem.

Whole body active vibration control of passenger biodynamics in quarter car model under random road excitations using ANFIS gain tuned PID-super twisting control

In this research, human biodynamics in the quarter vehicle suspension model is used for studying the effect of road excitations on human body. The random road excitation is developed using ISO 8608:2016 standard for simulation work. For achieving the better ride comfort of human body, two different controllers are developed and implemented in main suspension of active quarter car model. The designed controllers include PID based super twisting control (PID-STC) and ANFIS gain tuned PID based super twisting control (AGTPID-STC). The designed ANFIS system is used to enhance the effectiveness of PID-STC controller. The ride comfort results of human biodynamic model are compared for passive and active control strategy cases for the acceleration and displacement responses. ISO 2631-1:1997 standard is also used for vibration response study in the most sensitive frequency range of 4–8 Hz for human body. Based on the simulation based graphical and mathematical results, it can be decided that AGTPID-STC controller can highly supress the undesirable effect of road induced excitaions on human body parts i.e. head and neck, upper torso, viscera and lower torso respectively compared to other control strategies.

Optimized state feedback control of quarter car active suspension system based on LMI algorithm

Suspension systems are applied in vehicles so as to improve the passengers ride comfort, vehicle stability and better road handling when the vehicle moves on roads with bumps and terrains. In this paper, Linear Matrix Inequality (LMI) and linear quadratic regulator (LQR) controllers were proposed and this was also compared with passive suspension system. Using nonlinear quarter car active suspension system model with hydraulic actuator to reduce the effect of bumpy road surfaces on vehicle and hence improve passenger ride comfort. Vehicle body suspension travel and wheel deflection were measured to determine the performance of the active suspension system. Mean absolute error (MAE) and integral square error (ISE) were used as the performance indexes, thus a MAE and ISE of passive 75.01%, LQR 82.65% and LMI 89.11% and passive 4.11x10−6, LQR 3.24x10−6 and LMI 2.19x10−6 respectively were recorded. Based on the simulation results and analysis, the LMI based control performs better in minimizing vibration effects and also guarantee better ride quality and vehicle stability when compared to the conventional LQR and the passive suspension system.

Endocrine Composite Skyhook-Groundhook Control of Electromagnetic Linear Hybrid Active Suspension

In order to effectively improve vehicle riding comfort, handling stability, and realize vibration energy recovery, a new kind of electromagnetic linear hybrid active suspension (EMLHAS) integrated with linear motor and solenoid valve shock absorber is put forward. Firstly, for the analysis of the suspension performance, a quarter dynamic model of EMLHAS is established. At the same time, the mathematical models of a linear motor, including the active state and energy-regenerative state, are found. The correctness of mathematical models for the linear motor in the active and energy-regenerative states is verified by means of characteristic tests. Moreover, the velocity characteristic tests of solenoid valve shock absorber are carried out to determine its mathematical polynomial model in the semiactive state. Then, a new kind of multimode endocrine composite skyhook-groundhook control strategy is proposed. The suspension motion is divided into four modes according to the driving conditions of the vehicle. An endocrine control with long feedback and short feedback is combined with the skyhook-groundhook control. The control laws of the skyhook-groundhook controller and endocrine controller are, respectively, designed. Finally, the simulation analysis of suspension dynamic performance and energy-regenerative characteristic is done. The results show the control effect of endocrine composite skyhook-groundhook control is better than that of skyhook-groundhook control, which improves vehicle riding comfort and handling stability. Moreover, part of vibration energy is recovered.

Performance analysis of a new hydropneumatic inerter-based suspension system with semi-active control effect

This paper develops a hydropneumatic inerter-based suspension system theoretical model to analyze its performance, based on the mechanical network theory of inerter and semi-active control. Comparison of the stiffness and damping characteristics among a passive hydropneumatic suspension system, semi-active hydropneumatic suspension system based on skyhook control, and hydropneumatic inerter-based suspension system is conducted. Moreover, the relationship between the internal coefficient of the inerter and the damping coefficient of the hydropneumatic suspension is investigated. The simulation results of the flow–volume curves of the hydropneumatic inerter-based suspension system are close to those of the semi-active hydropneumatic suspension system based on skyhook control. Furthermore, the performance of a quarter vehicle model with the hydropneumatic inerter-based suspension system is analyzed and compared to that with the semi-active hydropneumatic suspension system based on skyhook control. The simulation results show that the performance of the hydropneumatic inerter-based suspension system is as good as that of the semi-active hydropneumatic suspension system based on skyhook control, which means that the hydropneumatic inerter-based suspension system can achieve similar performance for semi-active control suspension. Finally, a prototype is developed, and a comparative bench test is carried out to verify the accuracy of the simulations. In addition, the hydropneumatic inerter-based suspension system can achieve semi-active control performance without additional hardware or energy loss.

Using point symmetry in finite element analyses

This paper presents the conditions in which a large class of structural problems having a geometric and material type of symmetry, i.e. point symmetry, may be used as a half model to reduce the computational effort. This type of symmetry may be used in finite element modelling to analyze a large class of usual problems especially for linear (static and modal), and for nonlinear analyses when it is necessary to run huge models avoiding the more complex substructuring techniques. First, all the theoretical aspects are introduced and presented using simple 2D models and then a 3D approach is considered to include all six DOFs per node that may be used in a structural analysis. Then, a practical problem, having one plane of reflective symmetry and point symmetry is described and analyzed for linear static analysis considering two different finite element models: an approximate shell model and an accurate solid based model. For each of the two models, full, half due to the reflective symmetry, and then quarter models (due to the mixed reflective and point symmetries) were analyzed, and the advantages of considering point symmetry are presented.

A Novel Endocrine Composite Fuzzy Control Strategy of Electromagnetic Hybrid Suspension

To effectively improve the vehicle suspension dynamic performances, minimizing discomfort of passengers and realize vibration energy recovery, a new kind of electromagnetic hybrid suspension (EMHS) system with parallel structure of linear motor and solenoid valve shock absorber is put forward. The linear motor actuator can work at the active state for active control or energy-regenerative state for energy recovery, the solenoid valve shock absorber work at the semi-active state for damping control. Firstly, for the analysis of the hybrid suspension, a quarter dynamic model of EMHS is established. Meanwhile, the mathematical models of linear motor actuator and solenoid valve shock absorber are founded, respectively. Then, for the better suspension control effect based on fuzzy control strategy, a novel endocrine composite fuzzy control strategy is designed. By learning the biological endocrine hormone regulation mechanism, the endocrine control with long feedback and ultra-short feedback is designed. The control laws of the fuzzy controller and endocrine controller are, respectively, designed. Finally, the simulation analysis of suspension dynamic performances and energy-regenerative characteristics is done, respectively. At the same time, the bench test is carried out based on the rapid control prototype with dSPACE platform. The results show the control effect of endocrine composite fuzzy control is better than that of fuzzy control, which improves the dynamic performances. Moreover, part of vibration energy is recovered.

A New Aircraft Taxiing Model Based on Filtering White Noise Method

The conversion relationship between power spectral density (PSD) and international roughness index (IRI) was studied based on the filtering white noise method with variable sampling frequency using a quarter vehicle model. Six-degree-of-freedom dynamic equations of the whole aircraft taxiing were obtained considering the lift, upstream and downward bump, roll and pitch motion of the airframe. And then the dynamic load factors of the aircraft wheels under different pavement roughness and various airspeeds were solved by SIMULINK toolbox. The results shown that the mean dynamic load is independent of the pavement roughness, whose values are approximately equal to the load when the aircraft glided on the smooth pavement. The worse the pavement roughness, the greater the maximum dynamic load factor. There are approximately linear relationships between IRI and the maximum dynamic load. When the aircraft glides at low airspeed, the dynamic load increases as the increasing of airspeed. Then the maximum dynamic load factor decreases with the increase of running velocity. Moreover, the formulas for calculating the wheel dynamic load factor under the coupling action of pavement roughness and airspeed were proposed, which could be used to calculated the distribution of the dynamic load in longitudinal direction of the runway and determine the dynamic load values in airport pavement design.

Optimal Sliding Mode Control Method for Active Suspension Control

A non-linear quarter car vehicle model is used in this study, for developing an active suspension control algorithm. The control method used is optimal sliding mode control, along with feedback linearization technique for compensating the nonlinear aspects of the plant. In addition to the work in recent literature that applies these control methods, estimation of the static suspension deflection; i.e. vehicle sprung mass is performed. Through simulation results, it is shown that correct information of vehicle sprung mass, compared to taking it as a constant parameter in control design, improves the performance of the controller. This in turn, reduces the sprung mass acceleration level, and enhances ride comfort.

Vehicle model response in frequency domain

The offered article deals with one of the possibilities of numerical analysis of the vehicle response in frequency domain. It works with quarter model of vehicle. For the selected computational model of vehicle it quantifies the Frequency Response Functions (FRF) of both force and kinematic quantities. It considers the stochastic road profile. The Power Spectral Density (PSD) of the road profile is used as input value for the calculation of Power Spectral Density of the response. Al calculations are carried out numerically in the environment of program system MATLAB. When we know the modules of FRF or the Power Response Factors (PRF) of vehicle model the calculation of vehicle response in frequency domain is fast and efficient.

Application of efficient TEP FE computation on accurate fabrication of cylindrical leg structure of jack-up rig

Cylindrical leg structure is an essential component of jack-up rig, and its fabrication accuracy will significantly influence the operation performance and service lift. Due to the welding distortion generated during rack and cylinder joining and its effect on dimensional profile of cylindrical leg structure, the experiment to fabricate the cylindrical leg structure and dimensional measurement were conducted in advance, and highly efficient Thermal Elastic Plastic (TEP) FE computation with Iterative Substructure Method (ISM) and OpenMP parallel computation was proposed and employed for welding distortion prediction. Simplified cylinder FE model was considered to clarify the mechanism of dimensional variation in advance, and efficiency of proposed TEP FE computation was also demonstrated. Quarter FE model of rack and cylinder welded structure was then employed due to its symmetrical feature while computed results have a good agreement comparing to the measurement. Meanwhile, in order to improve the fabrication accuracy, bead-on-plate welding on inner surface of cylindrical leg structure was numerically examined, while inverse deformation can be generated and has significant influence to mitigate welding distortion during rack and cylinder joining.

Comprehensive Analysis and Optimization of Dynamic Vibration-Absorbing Structures for Electric Vehicles Driven by In-Wheel Motors

Distributed-drive electric vehicles (EVs) replace internal combustion engine with multiple motors, and the novel configuration results in new dynamic-related issues. This paper studies the coupling effects between the parameters and responses of dynamic vibration-absorbing structures (DVAS) for EVs driven by in-wheel motors (IWM). Firstly, a DVAS-based quarter suspension model is developed for distributed-drive EVs, from which nine parameters and five responses are selected for the coupling effect analysis. A two-stage global sensitivity analysis is then utilized to investigate the effect of each parameter on the responses. The control of the system is then converted into a multiobjective optimization problem with the defined system parameters being the optimization variables, and three dynamic limitations regarding both motor and suspension subsystems are taken as the constraints. A particle swarm optimization approach is then used to either improve ride comfort or mitigate IWM vibration, and two optimized parameter sets for these two objects are provided at last. Simulation results provide in-depth conclusions for the coupling effects between parameters and responses, as well as a guideline on how to design system parameters for contradictory objectives. It can be concluded that either passenger comfort or motor lifespan can be reduced up to 36% and 15% by properly changing the IWM suspension system parameters.

Road roughness acquisition and classification using improved restricted Boltzmann machine deep learning algorithm

Purpose To realize classification of different pavements, a road roughness acquisition system design and an improved restricted Boltzmann machine deep neural network algorithm based on Adaboost Backward Propagation algorithm for road roughness detection is presented in this paper. The developed measurement system, including hardware designs and algorithm for software, constitutes an independent system which is low-cost, convenient for installation and small. Design/methodology/approach The inputs of restricted Boltzmann machine deep neural network are the vehicle vertical acceleration power spectrum and the pitch acceleration power spectrum, which is calculated using ADAMS finite element software. Adaboost Backward Propagation algorithm is used in each restricted Boltzmann machine deep neural network classification model for fine-tuning given its performance of global searching. The algorithm is first applied to road spectrum detection and experiments indicate that the algorithm is suitable for detecting pavement roughness. Findings The detection rate of RBM deep neural network algorithm based on Adaboost Backward Propagation is up to 96 per cent, and the false positive rate is below 3.34 per cent. These indices are both better than the other supervised algorithms, which also performs better in extracting the intrinsic characteristics of data, and therefore improves the classification accuracy and classification quality. Additionally, the classification performance is optimized. The experimental results show that the algorithm can improve performance of restricted Boltzmann machine deep neural networks. The system can be used for detecting pavement roughness. Originality/value This paper presents an improved restricted Boltzmann machine deep neural network algorithm based on Adaboost Backward Propagation for identifying the road roughness. Through the restricted Boltzmann machine, it completes pre-training and initializing sample weights. The entire neural network is fine-tuned through the Adaboost Backward Propagation algorithm, verifying the validity of the algorithm on the MNIST data set. A quarter vehicle model is used as the foundation, and the vertical acceleration spectrum of the vehicle center of mass and pitch acceleration spectrum were obtained by simulation in ADAMS as the input samples. The experimental results show that the improved algorithm has better optimization ability, improves the detection rate and can detect the road roughness more effectively.

Road Profile Identification by Genetic Algorithm withMultistage Search using Vibration Response of a QuarterVehicle Model

Vehicle performance is affected by road profile since the road profile supplies vibration to the vehicle. The road profile can be identified by vibration response of the vehicle. By using the vibration response, road profile identification can be, in fact, formulated as a single-objective optimization in which an objective, a minimization criterion, is the numerical difference between vehicle vibration response of actual road profile and that of predicted road profile. This paper present multistage search in genetic algorithm (GA), an optimization algorithm, in the road profile identification. In the multistage search, a solution is divided into a number of parts and each part is consequently evolved as GA process separately from other parts. A quarter vehicle models with two test cases of double bump on road profiles are used. Simulation runs reveal that the multistage search can enhance performance of GA. In addition, the multistage search using the least number of decision variables in each solution part gives the best results of the optimized solutions.

A Novel Method of Residual Strain Analysis Via a Non-Bonded Interface Technique in Combination With the Circular Grid Analysis Method

AbstractA novel non-bonded interface technique (NBIT) is used to analyze internal residual strain by combining a pre-split sample of AISI 4340 steel with the circular grid residual strain analysis technique. NBIT is compared with an implicit non-linear finite element (FE) model using LS-DYNA. A split FE model was compared with a quarter FE model to determine the split interface that causes an average difference of 9.0% on the residual von Mises strain field from a 588.6 N indentation. The homogeneous FE quarter model was then compared with the experimental split model using 588.6, 981.0, and 1471.5 N indentation forces. An average displacement difference of 3.92 µm was found when comparing the experimental split and FE homogeneous samples from a 588.6 N indentation. The internal residual major and minor principal strains from the split experimental sample and homogeneous FE model were compared for each indentation force. The minor principal strain results show the 588.6, 981.0, and 1471.5 N indentation forces resulted in a difference between the experimental split and homogeneous FE model of 28.5%, 34.8%, and 26.0%, respectively. The difference between the comparisons was explained by the inability of the FE model to simulate local non-homogeneous material properties such as grain composition and orientation whereas NBIT does. NBIT can be used for micro- or macro-scale residual strain analysis as the spatial resolution is highly adjustable.

Active Suspension with Model Predictive Control

This paper examines the performance of Model Predictive Control (MPC) scheme for an Active suspension. A vehicle suspension is designed to provide superior ride comfort and road handling characteristics. Unlike passive suspensions, the Active suspension can change the dynamic of suspension in real-time by injecting force into the system. MPC allows the active suspension to provide better and consistent passenger comfort and road handling capabilities for different road profile. Even though long back, the idea of active suspension conceived, the prohibitive cost and complexity restricted its usage. In recent years active suspension is receiving more and more attention with users preferring a high-end car. In an active suspension for the real-time adjustment of the control force, need a design of a controller. In literature, many controllers used such as Proportional Integral Derivative (PID), Linear Quadratic regulators (LQR), Fuzzy logic controller, Artificial Neural Networks (ANN). In this paper, revealed a model predictive control arrangement for Active suspension model. MPC is an optimal control scheme which uses a model of plant for predicting the future output. The control inputs are optimized such that these predicted outputs meet the desired level of performance. Tested the MPC control scheme is using a bench-scale replica of Quarter active suspension model from QUANSER. To better appreciate the capabilities of the MPC Control Scheme, compared the performance of the active suspension with that of an LQR control scheme, and passive suspension.

Design and analysis of output feedback constraint control for antilock braking system based on Burckhardt’s model

PurposeThe purpose of this study is to improve vehicles’ brake stability, the problem of constraint control for an antilock braking system (ABS) with asymmetric slip ratio constraints is concerned. A nonlinear control method based on barrier Lyapunov function (BLF) is proposed not only to track the optimal slip ratio but also to guarantee no violation on slip ratio constraints.Design/methodology/approachA quarter vehicle braking model and Burckhardt’s tire model are considered. The asymmetric BLF is introduced into the controller for solving asymmetric slip ratio constraint problems.FindingsThe proposed controller can implement ABS zero steady-state error tracking of the optimal wheel slip ratio and make slip ratio constraints flexible for various runway surfaces and runway transitions. Simulation and experimental results show that the control scheme can guarantee no violation on slip ratio constraints and avoid self-locking.Originality/valueThe slip rate equation with uncertainties is established, and BLF is introduced into the design process of the constrained controller to realize the slip rate constrained control.

Design, fabrication, and evaluation of a passive deployment mechanism for deployable space telescope

This article presents a high precise deployment mechanism for a deployable space telescope to facilitate satellite miniaturization. It is designed with a passive deployment mechanism utilizing a spring hinge. In particular, the customized modules and an assembly jig are specifically designed to reduce alignment errors. To confirm the feasibility of the designed mechanism, three alignment errors that influence the optical performance of the structure—tilt, de-center, and de-space—are theoretically analyzed for quarter, half, and full model, respectively. In the case of quarter model, significant results are obtained as a tilt of 21.12 µrad, a de-center of 2.20 µm, and a de-space of 1.71 µm. Based on the theoretical analysis, a deployment mechanism of the quarter model is fabricated, and the alignments of the deployment mechanism are experimentally investigated with a measurement platform consisting of five non-contact-based laser displacement sensors. In addition, the influence of gravity on the alignment error is analyzed and compensated by investigating the tendency of the alignment error according to the rotation degree of the measurement model for the direction of gravity. As a result of the gravity compensation, the proposed mechanism gives acceptable alignment errors as a tilt of 30.04 µrad, de-center of 8.92 µm, and de-space of 4.03 µm, which are controllable by employing the conventional focusing mechanism.

Calculating of stress intensity factors of soldered joints with multiple cracks

<span>This paper presents the solution of stress intensity factors of multiple cracks at the joint between two materials. Based on the literature survey, there are tremendous number of works found on the study of edge and central cracks. On the other hand, several papers on the multiple cracks can be also be found in open literature. However, the work on multiple cracks with different crack sizes are hard to find. Therefore, this paper focuses to study the crack interaction obtained from different crack sizes. ANSYS APDL is used to model and solve the problems considering the cracks embedded in the plain strain plate under tension stress. There are two important parameters are considered such crack sizes and mechanical mismatches between joint and based materials. Since the crack is symmetrical, only a quarter model is used and verified. Based on the numerical simulation, it is found that two factors are significantly affected the multiple cracks at the joints such as mechanical mismatches and relative crack sizes.</span>

A monitoring-based approach for evaluating dynamic responses of riding vehicle on long-span bridge under strong winds

Serviceability performances of the long span bridge during strong winds, including the safety and comfort condition of driving road vehicle on the bridge, have attracted more and more attention in recent years. The dynamic behavior of the riding vehicle is essential for serviceability performance assessment. The vehicle-bridge coupling (VBC) simulation, featured as time-consuming, is traditionally applied, however, cannot meet the requirement for timely decision. Therefore, a monitoring-based approach, with the hybrid combination of in-situ structural health monitoring (SHM) data and dynamic simulation of single vehicle model, is presented in this paper to estimate the vehicle dynamic responses in a more efficient way. A numerical case study of a quarter vehicle model riding on a simply supported beam bridge is presented to validate the proposed approach. The first step is to investigate the feasibility of reproducing structural responses with the data from limited sensors using interpolation methods. Subsequently, dynamic responses of the riding vehicle are estimated using the monitoring-based approach. The influences of random traffic and wind loads are also considered. The estimated vehicle responses generally match VBC-based results, which proves reliability of the monitoring-based approach. Furthermore, the SHM data of a long-span bridge are utilized to investigate the potential usage of the proposed method. In particular, the dynamic responses of a popular light truck on the bridge and rigid road are respectively estimated and compared with each other. Results show that, among all the factors, i.e., bridge vibration, wind loads, and road roughness, the bridge vibration contributes the majority to the vertical vibration of the vehicle. For the lateral and torsional vibration of the vehicle, wind forces and bridge vibration are dominant factors. To summarize, the monitoring-based approach could help to estimate the dynamic responses of the riding vehicle on the bridge with a good reliability, regardless of the operation condition of the bridge, and provide timely and reliable information for serviceability and safety assessment.