“Functional integration” is to integrate two or multiple systems or mechanisms that are independent with each other and to realize the two or multiple functions using only one actuation system. Maximization of engineering applications of actuation systems could be achieved through the use of the “functional integration” concept-based structural design. In this article, an integrated semi-active seat suspension, mainly composed of a switching mechanism, a transmission amplification mechanism, and a damping force- or torque-controllable rotary magnetorheological (MR) damper working in pure shear mode, for both longitudinal and vertical vibration attenuation, is proposed, designed, and fabricated. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. Both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. The ...

Integrated semi-active seat suspension for both longitudinal and vertical vibration isolation

The development of a methodology that enables the optimization of passive suspension system parameters, providing a group of optimal solutions, could be an excellent approach to obtain a fast improvement tool during the design of suspension systems. Thus, this paper proposes a methodology for the multi-objective optimization of the passive suspension system of a full-car model travelling in a random road profile. For this purpose, a numerical-computational routine is developed, which integrates the NSGA-II with the vertical dynamic analysis, in the time domain, of an eight degrees-of-freedom vehicle model with a seat. Three objective functions, which take into account passenger comfort and safety, are considered. The proposed methodology provides a Pareto-optimal front, which consists of a set of non-dominated solutions that minimize the three objective functions. Comparing the results of the dynamic analyses of the vehicle model with optimized and non-optimized suspension systems, it was verified that the optimization allowed a reduction of up to 21.14% of the weighted RMS value of the driver seat vertical acceleration, a parameter directly related to comfort, while maintaining or improving the trade-off with safety. The Pareto-optimal front has proven to be an excellent support tool to aid the designer in the determination of the parameters that best fit the suspension system to produce the desired dynamic behavior in vehicles. Thus, the proposed optimization methodology can be recommended as an effective tool for the optimal design of passive suspension system parameters. Finally, this work shows that the design of suspension parameters can be done taking into account passenger comfort and safety at same time.

Multi-objective optimization of the suspension system parameters of a full vehicle model

An approach for minimizing the number of objective functions in the optimization of vehicle suspension systems

The efficiency of passive vibration damping on the pilot seat of piston propeller aircraft

Quarter-car model is in use for years to study the car dynamics. The objection of this paper is to examine the dynamics of a car passing a circular hump for sake maintaining ride comfort for the passengers. Passive suspension elements are considered with suspension damping coefficient in the range 1 to 15 kNs/m. Car speed in the range 5 to 25 km/h is considered when passing the hump. Important phenomenon evolved from the analysis of the car dynamics which is performed using MATLAB. The mathematical model of the quarter-car model is derived in the state form and the dynamics are evaluated in terms of the sprung mass displacement and acceleration. The effect of suspension damping and car speed on the sprung-mass displacement and acceleration is examined. The study shows that for ride comfort the car speed has not to exceed 6.75 km/h when passing a circular hump depending on the suspension damping. .

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Car Dynamics using Quarter Model and Passive Suspension, Part I: Effect of Suspension Damping and Car Speed

This paper presents an optimal vehicle and seat suspension design for a half-car vehicle model to reduce human-body vibration (whole-body vibration). A genetic algorithm is applied to search for the optimal parameters of the seat and vehicle suspension. The desired objective is proposed as the minimization of a multi-objective function formed by the combination of seat suspension working space (seat suspension deflection), head acceleration, and seat mass acceleration to achieve the best comfort of the driver. With the aid of Matlab/Simulink software, a simulation model is achieved. In solving this problem, the genetic algorithms have consistently found near-optimal solutions within specified parameters ranges for several independent runs. For validation, the solution obtained by GA was compared to the ones of the passive suspensions through sinusoidal excitation of the seat suspension system for the currently used suspension systems.

/pdf/optimal-seat-and-suspension-design-for-a-half-car-with-4mmxjd6g1w.pdf

Optimal Seat and Suspension Design for a Half-Car with Driver Model Using Genetic Algorithm

The extent to which an individual is harmed by indoor air pollution depends on their total exposure to pollutants, the duration of exposure, and the concentration level. Various factors contribute to the concentration levels and duration of exposure to the indoor pollutant. This study approached knowledge from a multitude of disciplines (e.g., epidemiology, virology, mechanical, etc.) and showcased them from an architectural point of view. Understanding the effects of these factors on contaminant dispersion in built environments can lead to the design of healthier living spaces. Several factors contribute to contaminant dispersion and escalate health risks in the built environment. These factors are not straightforward; but rather a complex interaction between several environmental factors. Building designs, site layout, and space distribution can contribute to the concentration level and duration of exposure to the indoor pollutant. Ventilation parameters such as ventilation exchange rate, airflow distribution patterns, and their overall direction are vital in controlling and diluting the pollutants' concentration levels. The study also shows that other factors, such as relative humidity, temperature, convective transport phenomena, and furniture arrangement, significantly influence indoor airflow and pollutant dispersion. Understanding these factors is critical to eliminating or reducing occupants’ exposure to indoor air pollutants found in the built environment.

Mohamed Shebl

Papers

Optimal Seat and Suspension Design for a Half-Car with Driver Model Using Genetic Algorithm

Factors Affecting Pollutants' Dispersion and Concentration Levels in the Built Environment

Modelling and optimization for an operating giant gas plant in Egypt