The shape optimization of a rigid inclusion in an elastic plane under concentrated loads is considered. The conformal mapping technique and extended Schwarz principle integrated with the analysis of singularity of complex stress functions are adopted. And a number of examples of the rigid inclusion with different shapes, such as elliptical, triangular and square inclusion, to account for a wide range of shape variations are discussed, Numerical results and graphs show that the maximum interface stresses vary with the shape of inclusion. And the shape resulting in minimum interface principal stress is obtained. Some suggestions are made in regard to the design of the shape of rigid inclusion.

A model of composite materials consisting of a continuous matrix with multiple elliptical rigid inclusions was considered. The problem of interfacial stress maxima varying with shape of inclusions was solved accurately. Using the conformal mapping technique integrated with the Laurent expansion method and coordinate transformation, complex stress functions that represent the interaction of elliptical rigid inclusions arbitrarily distributed in the isotropic elastic matrix are constructed, and boundary conditions of every inclusion are satisfied. By circulation integrals, boundary equations are transformed into linear algebraic equations. Under the uniform tensile load at infinity, interfacial stress formulas, with numerical results and graphs, showing interfacial stress maxima varying with the shape of inclusions, were obtained. A comparison was made with other numerical results to demonstrate the superiority of the proposed model and accuracy of the solutions.

A mathematical model was built up for hydroelectric active suspension in vehicles. Relying on optimal control theory, an optimal controller was designed. Suboptimal control strategy for active suspension was studied using minimized norm. A new method of sensitivity analysis for determining the feedback variable was proposed and used to solve problems in selecting feedback variables for engineering applications. Based on actual vehicle parameters and theoretical studies, the suboptimal controller was designed. It was then simulated and tested with rig experiment. Simulation and experimental results shows that the suboptimal control strategy and sensitivity analysis proposed are feasible. It also shows that the suboptimal and optimal controllers have the same effects on vehicle vibration isolation. Within lower frequency domains, they can both reduce vehicle body acceleration and tire displacement to some degree and are effective in enhancing the riding comfort and handling stability.

This paper develops a ride dynamics model and presents a method to apply a linear robust control and fuzzy logic control to a high mobility off-road tracked vehicle. To avoid the complexity of modeling track system, it is classified as unknown dynamics and disturbances. Firstly, a nonlinear off-road tracked vehicle model-including bump stop and shock absorber nonlinearities is developed. Subsequently, a new robust fuzzy logic control strategy is developed and applied to tracked vehicle. In the process of designing robust controller, a linearized model is used with uncertainties and disturbances. The errors between linearized model and actual nonlinear tracked vehicle model are compensated by fuzzy logic controller. Finally, control performances to isolate vibration from bump are evaluated through computer simulation under Matlab and ADAMS environments.

Based on full-car model, an integrated control strategy which consists of filtered LQR and sky-hook damping control is studied. Adopting easily measurable vehicle body accelerations and suspension deflections, a filtered LQR controller was designed. LQR controller enhances vehicle ride quality on a large scale. Leveling on vehicle attitude was implemented by controlling suspension deflections and movements of vehicle body heave, pitch and roll. After these, vehicle stability is promoted when excited by discrete load disturbances. In the process of designing attitude controller, a method named by input decoupling transformation was used to transfer the movement of vehicle body heave, pitch and roll to suspension related movement. Simulation results show that active suspension controlled by attitude controller plus ride controller, compared with passive suspension and active suspension controlled by exclusive ride controller, can not only enhance ride comfort, but also promote attitude leveling ability for road vehicle. So, this control strategy and full car controller in this paper are of researching and application values in engineering practice.