Roslan Abdul Rahman

Vehicle ride performance with semi-active suspension system using modified skyhook algorithm and current generator model

This paper presents the simulation of a semi-active suspension system by using designed parameter model of magnetorheological (MR) damper. The design is based on the performance of the original equipment shock absorber of a passenger vehicle. A 7DOF of vehicle ride model was developed and validated in order to study the performance of a passive suspension system and the designed semi active suspension system. A controller known as modified skyhook algorithm and current generator model was used in the semi-active suspension system. The simulation results show that the semi active suspension system give significant improvement on vehicles ride comfort.

Semi active suspension system performance under random road profile excitations

This paper presents an investigation on the performance of algorithms in semi active suspension system. A validated full car model was used for this purpose. The semi active suspension system is using the magnetorheological (MR) damper as its variable damping damper element. The Skyhook and Modified Skyhook algorithms are used to control the operation of the MR damper model in the semi active suspension systems of a full car model. The parameters of the algorithms were optimized to ensure the highest degree of ride comfort performance of the full car model based on a criteria. The models jerk, vertical acceleration, vertical displacement, roll rate, roll angle, pitch rate and pitch angle are investigated in this paper in terms of root-mean-square (RMS) values and time domain results. It was found out the overall performance of skyhook-controlled system is slightly better than the modified skyhook-controlled system by 3.2 percent due to good algorithm performance in improving pitch motions of the vehicle. The modified skyhook algorithm is better in improving vehicle vertical motions and roll motions compared to the Skyhook system.

Experimental Investigation on Free Vibration of Foam-Core Sandwich Plate with and without Circular Polymer Columns

Free vibration modes of foam-core sandwich plates with and without polymer columns were experimentally identified from frequency response tests. The responses were made at selected locations on the plate surface by attaching a single-axis accelerometer to measure out-of-plane response. Resonant frequencies, relative damping ratios and mode shapes were established for the lowest 3 out-of-plane modes found in the frequency range of 0-900 Hz. The results show that the vibration characteristics were affected by the sandwich structure configuration and material properties.

Active suspension system in improving ride and handling performance of electric vehicle conversion

This paper presents an evaluation on passenger vehicles ride and handling performance when converted into an electric vehicle (EV). The evaluations were done using a validated 14 degrees of freedom ride and handling model. The mathematical modelling of vehicles ride and handling model as well as its validations are described. Two types of experiments were performed to validate the developed simulation model; the ride test and the handling test. The validated simulation model was used to evaluate the vehicles ride and handling performance of the vehicle when converted into an electric vehicle. The evaluation involves two weight distribution ratios which are 60:40, for normal vehicle and 40:60 for EV conversion. The validated simulation model used active suspension system in order to improve the EV conversions ride and handling performance. It is found that modification into EV affects vehicles handling performance quite significant but not ride performance. The EV conversions weight, which is distributed towards the rear of the vehicle, causes the vehicle to travel off from its original travelling path. The application of active suspension system is proposed to improve EV conversions handling performance as well as its ride comfort performance.

Optimization of heavy duty truck chassis design by considering torsional stiffness and mass of the structure

The torsional stiffness is one of the most important properties of chassis that significantly affect its dynamic characteristics such as handling and rollover. The torsional stiffness is desired to be as high as possible since low torsional stiffness may cause resonance or vibration. There are several types of heavy duty truck chassis that used in Malaysia and no information about the torsional stiffness magnitude of it. In this work, the torsional stiffness of several existing types of heavy duty truck chassis and some modified types, namely: arc model, block model, hole model, multi holes model and fully block model are determined using finite element method. The torsional stiffness of several chassis was compared together with the weight comparison in order to get the best design of chassis that has high torsional stiffness and low weight. Based on the simulation result, the multi holes model is the best design due to the highest of torsional stiffness and the lowest mass.

Dynamic Response of Commuter Rail Vehicle under Lateral Track Irregularity

Lateral track irregularities normally occur when both rail lines have some displacement laterally with respect to the original track due to prolonged exposure to sun’s heat, or may also arise from specific features such as switch and crossing work of track. These track irregularities will cause unwanted body vibration of commuter rail vehicle. These vibrations have to be suppressed for the purpose of ride comfort. This paper presents two control strategies in semi-active suspension systems which are PID and disturbance rejection control to improve passenger ride comfort. A half car model of commuter rail vehicle with three-degree-of-freedom (3-DOF) was developed based on Second Newtons Law. Vibration analyses based on simulation results in time domains are compared with passive system using MATLAB-Simulink software. The results show that the semi-active controllers are able to suppress rail vehicle body responses effectively.

Effect of Manufacturing Process on Free Vibration of Foam-Core Sandwich Plate

In this paper, the effect of the manufacturing process on free vibration modes of foam-core sandwich plate were experimentally identified from frequency response tests. Three types of foam-core sandwich plate that fabricated by using hand lay-up, vacuum bagging and vacuum infusion process were tested and compared. The responses were made at selected locations on the plate surface by attaching a single-axis accelerometer to measure out-of-plane response. Resonant frequencies, relative damping ratios and mode shapes were established for the lowest 3 out-of-plane modes found in the frequency range of 0-900 Hz. The results show that the vibration characteristics were affected by the fabrication process of the sandwich structure.

Improving Electric Vehicle Conversion’s Ride and Handling Performance Using Active Suspension System

This paper present an evaluation on passenger vehicle’s ride and handling performance if being converted into an electric vehicle. The mathematical modelling of vehicle’s ride and handling model as well as its validations are described. The simulation model was used to evaluate the vehicle’s ride and handling performance when converted into an electric vehicle. The validated simulation model was also integrated with an active suspension system in order to improve the EV conversion’s ride and handling performance. It was found that the modifications towards an EV conversion only affect the vehicle’s handling performance significantly. The modifications which change the weight distribution, which biased to the rear of the vehicle, will cause the vehicle to travel off from its original traveling path. The application of active suspension is possibly being used in correcting this condition as well as further improving the EV conversion’s ride comfort performance.

Finite Element Analysis of Corroded Truck Chassis Using Sub Modeling Technique

Recently the truck industry has experienced a large push to overcome the increasing demands of higher performance, lower weight, and longer life of components, all this at a reasonable cost and in a short period of time. Conducting experimental test in the early stage of design is time consuming and expensive. In order to reduce the cost, it is important to conduct simulation using numerical methods by software to find the optimum design. In practice, many of the finite element objects are very large so it makes a difficulty in meshing and also in analysis of the model. It very takes time and need a lot of memory of computer. Submodeling technique offer the solution about that problem. This paper presents the submodeling technique that applied on the corroded truck chassis.