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A new approach is proposed to solve for the eigen-values and eigen-functions of circular plates with circular holes by using the Rayleigh Ritz Method. In this method, the spatial solution is expanded into separable functions in terms of polar coordinates. While trigonometric functions are used along the circumferential direction, the Boundary Characteristic Orthogonal Polynomials build the radial shape functions. Written in terms of the assumed functions, the potential and kinetic energies are modified in order to account for the holes. Although the proposed approach is applicable for plates with different boundary conditions and different hole shapes, the free vibration of a clamped circular plate with circular holes is considered in the present study. The edges of the holes are free. Four different case studies are carried out. The results of the Rayleigh Ritz Method are compared with those available in the literature.

The larger chassis space requirements of hybrid vehicles necessitates considerations of the suspension synthesis with limited lateral space, which may involve complex compromises among performance measures related to vehicle ride and handling. This study investigates the influences of suspension linkage geometry on the kinematic and dynamic responses of the vehicle including the wheel load in order to facilitate synthesis of suspension with constrained lateral space. A kineto-dynamic half-car model is formulated incorporating double wishbone suspensions with tire compliance, although the results are limited to kinematic responses alone. An optimal synthesis of the suspension is presented to attain a compromise among the different kinematic performance measures with considerations of lateral space constraints. In the kineto-dynamic model, the struts comprising linear springs and viscous dampers are introduced as force elements.

Automotive suspensions invariably exhibit asymmetric damping properties in compression and rebound, which is partly attributed to asymmetric damping and in-part to the suspension linkage kinematics together with tire lateral compliance. Although automotive suspensions have invariably employed asymmetric damping, the design guidelines and particular rationale for such asymmetry has not been explicitly defined. The influences of damper asymmetry together with the suspension kinematics and tire lateral compliance on the dynamic responses of a vehicle are investigated analytically under bump and pothole excitations, and the results are interpreted in view of potential design guidance. A quarter-car kineto-dynamic model of the road vehicle employing a double wishbone type suspension comprising a strut with linear spring and multiphase asymmetric damper is formulated for the analyses.

After a long “incubation” period, MEMS are finally strongly coming out on the marked. The integrated telemetry and the photo-voltaic power source are among the attractive features of the integrated MEMS applications. The tendency is more and more seen to small integrators, which use OEMs and build systems for market demanded applications. However, the products offered by the market at this time are mostly limited to static detection or inertial systems. The temperature range of the dominant applications quite significantly limits the measurement capabilities of the system. Aerospace systems are not necessary falling within the normal temperature range. The need of enhanced performance and safety of the gas turbine engines require pressure measurements at temperature that exceed 500 °C. Apart from the physics, the principle of measurement, fabrication technology, signal data processing, packaging represents a challenging task.

A closed-loop articulated vehicle-driver model, incorporating the path errors, lateral accelerations of the two units and the rate of steering, is proposed to study the directional control behavior of the driver. The closed-loop driver-vehicle model is formulated upon integrating the yaw-plane model of a five-axle articulated vehicle and a comprehensive driver model. The driver model, incorporating the delays associated with the limb movement and muscle activities, is developed with an objective to minimize the lateral acceleration of vehicle, and the lateral position and orientation errors between the previewed and the actual path of the tractor. Various parameters required to describe the driver's contributions are identified through minimizing a weighted performance index subject to an array of limit constraints established from the reported data.

An articulated vehicle suspension comprising a parallel combination of passive energy restoring and dissipative elements and a feedback controlled force generator is analyzed using H2 control synthesis. The active suspension schemes based on limited-state measurements are formulated to minimize a performance measure comprising ride quality, cargo safety, suspension and tire dynamic deflections, and power requirements. The ride quality and the dynamic wheel load performance characteristics of these suspension schemes are compared to those of a vehicle with an ideal active suspension and an “optimum” passive suspension to demonstrate the performance potentials of the proposed limited-measurement-based suspension schemes.