Papers by Author: Ying Hou Jiao

Abstract: Shape memory alloy (SMA) is a type of smart material with huge driving force, and large driven displacement. Using SMA as the structure driver may force a bi-directional deformation structure that can achieve high efficiency and compact driving structure. SMA, together with elastic component, forms the two-way driving structure; however the two, if respectively serving as the driver, can enable the occurrence of the simplest bi-directional drivable structure. The offset structure constituted by SMA, not only can achieve two-way drive, and does not require continuous input of energy during the shape-stabilizing period. This paper studies the design methods of these two structures, gives the typical formulas, which makes possible efficient and compact bi-directional drivable structures.

Abstract: Current coach mainly use the passive rubber mount system to isolate vibration, it’s hard to meet the engine broadband range isolation requirements. In order to reduce the coach engine vibration’s influence on the ride comfort and operational stability, it’s proposed that a magnetorheological fluid powertrain mount system. Set up the six degrees of freedom dynamic model and 1/4 engine single freedom vibration model. Design a fuzzy controller, which the input is dynamic exciting force and second order main frequency, the output is control current. Simulate the three types systems with the help of software of MATLAB/SIMULINK and Fuzzy control toolbox. The result shows that when fuzzy controller works, adjustable damping effect is obvious, it can attenuate vibration in large degree. The magnetorheological hydraulic mount with the fuzzy control ,compared with rubber mount and traditional hydraulic mount, has better isolation effect. Its damp can be controlled real-time, and it can be effective in isolation within the broadband.

Abstract: To efficiently reduce vibration and noise of a plate, an optimization of passive constrained layer damping (CLD) is presented. The dynamic equation of a sandwich plate with CLD treatment is derived using Lagrange’s method. The assumed modes method is employed to solve the equation and obtain the vibrational energy and sound power, which are used as the objective of optimal design. A genetic algorithm of big mutation is employed to search for the optimum of the location of CLD treatment, the thicknesses of both the constraining layer and the viscoelastic layer and the shear modulus of the viscoelastic material with the restriction of added mass of the total CLD treatment. Numerical results show that for a simply-supported plate with a transverse force (1Hz~200Hz) applied at (0.8L_a, 0.8L_b), the optimized CLD significantly reduce the vibrational energy and sound power.

Abstract: In this paper, an optimization study of partially covered beam with a constrained viscoelastic layer is presented. An energy approach and Lagrange’s method are used to establish the governing equation of motion of a CLD covered beam, and the assumed modes method is employed in solving the equation to obtain the modal loss factors which are used as the objective of optimal layout. A genetic algorithm of big mutation is employed to search for the optimum of the patch’s location, the thicknesses of both the constraining layer (CL) and the viscoelastic layer (VL) and the shear modulus of the viscoelastic material with the restriction of added volume of the total CLD treatment. Numerical results show that the optima of the design variables are highly relevant to each other. The thinner constraining layer requires a softer viscoelastic material for an optimal damping treatment. The variation of the CL thickness decreases slowly and that of the VL thickness increases with the increase of the thickness of the CLD treatment. One end of optimal damping treatment locates closely one end of base beam.