Prof. Chunming Li

Shengli College in China University of Petroleum, China

Research Area: Mechanical Engineering and Automation

Brief Introduction:

Chunming Li, postdoctoral, joined China University of Petroleum (East China) in 2003 and served as a professor at Shengli College in China University of Petroleum. Mainly engaged in research work on mechanical dynamics, optimization methods, innovative methods, etc. Main lectures such as "Innovative Design of Machinery", "Optimized Design of Machinery", "Basics of Mechanical Design" and other courses. In the direction of dynamics research, in-depth research on intelligent rotors, multi-body systems, elastic rope systems, the main mechanism of the bull head planer, the main mechanism of the double-cylinder pump, the cadang mechanism, etc. The system carried out dynamic simulation research and found that the cadang pump has rigidity Impact; in the direction of optimization methods, in-depth research and systematic research on the theory of optimization methods; in the direction of innovation methods, in-depth research on psychology-based innovation methods, mechanical system innovation methods, institutional combination innovation methods, institutional exhaustive innovation Methods, etc., systematically carried out research on the theoretical system of the subject; in the direction of teaching methods, in-depth research on teaching methods based on memory characteristics, guiding students to learn independently, and prompting students to learn, etc., systematically carried out research on teaching theories. Published more than 60 academic papers, of which more than 10 were included in SCI and EI.

Title: The optimization algorithm of blind walking

Abstract: The basic idea of one-dimensional blind walking algorithm is introduced. Three steps of the algorithm are introduced, the first two of which are the forward and backward method to determine the interval of the extreme point. The application of this algorithm in the multi-dimensional unconstrained optimization method is introduced, such as the broken line negative gradient direction method applied to the negative gradient direction method, and the high-order objective function requirements found in the multi-dimensional Newton method (the second-order approximate fixed-point method). The topic report consists of the following parts:

1) The basic idea of blind walking.

2) Optimization steps of one-dimensional blind walking method.

3) Negative gradient direction method of broken line.

4) Application of multidimensional Newton method.

5) Application of random direction method and polyhedron deformation method.

6) Relevant references.

Assoc. Prof. Meng-Ju Lin

Feng Chia University, Taiwan, China

Research Area: Micro-electro-optical-mechanical System; MEMS Mechanics; Micro Scraping Machining; Non-silicon-based  Micromachining Optical Devices

Brief Introduction:

Meng-Ju Lin received the B.S. and Ph.D. degrees in power mechanical engineering from National Tsing Hua University, Hsinchu, Taiwan, in 1990 and 2002 and the M.S. degree in applied mechanics from National Taiwan University, Taipei, Taiwan in 1992. He is currently the associate professor in Department of Mechanical and Computer Aided Engineering, Feng Chia University, Taiwan. His research interests include sticking effect, squeeze film, thermal stress and fatigue problems in MEMS, micro scraping machining, non-silicon-based micromachining optical devices, and the micro torsion and focusing deformable mirror.

Title: Some bifurcation phenomena in MEMS

Abstract: It is known most theorems of classic physic are well applied in MEMS. However, some effects ignored in macro world become important in micro meter scale. Due to the increasing significant effect of such effects, there are bifurcation phenomena happening in MEMS. The bifurcation phenomena would be troublesome in MEMS. Sticking in wet etching and pull-in in electrostatically actuated MEMS are widely known. And they will damage the MEMS devices. For sticking problems, the mechanical stability and adhesion of microstructures under capillary forces are investigated. And a nondimensional elastocapillary number in terms of structure sizes and material properties is derived for center anchored circular plate. For pull-in phenomena, as applying enough voltage is on the structure, the structure will cause electrostatic adhesion due to the electrostatic force larger than the elastic recovery force. If the displacements are greater than 1/3 of the gap, unstable collapse will occur. However, bifurcation phenomena would have advantages for used in some MEMS structures. The well known bistable mechanism for exhibiting stable states in two distinct positions have advantages for their unique mechanical behaviors used in MEMS devices to achieve a high response, reduce power consumption and prevent external disturbances. A bistable criterion for double V-beam mechanisms is derived. This theoretical derivation of the criterion in terms of structure sizes and material properties is able to determining whether bistability can occur in micromechanically bistable mechanisms. It would help in MEMS device designs.