This paper proposes an optimization method for finding the optimal design of a bistable mechanism with a desired performance that is robust to structural and material uncertainties.Using interval numbers to characteri...This paper proposes an optimization method for finding the optimal design of a bistable mechanism with a desired performance that is robust to structural and material uncertainties.Using interval numbers to characterize the uncertainties in the structural parameters and materials,we present a nonprobabilistic multiobjective optimization model and transform it into a single objective optimization model using a penalty function.The sensitivity of the mechanical performance of bistable structures to uncertain parameters was analyzed,and the design parameters with notable effects on the bistable performance were identified as optimization variables.A neural network-based proxy model for the nonlinear characteristics of the bistable mechanism was established,and its accuracy was validated through finite element outcomes.Based on this model,a two-layer nested genetic algorithm was employed to solve the multiobjective robust optimization problem of the bistable structures with critical forces and a second stable position.The effectiveness of the optimization method was verified by comparing it with the finite element and experimental results.The proposed method was applied in the design of silicon-based inertial switches.展开更多
Compliant bistable mechanisms, devices with two distinct stable equilibrium positions, are used in a variety of applications, such as switches, clasps, and valves. Many kinds of compliant bistable mechanisms were prop...Compliant bistable mechanisms, devices with two distinct stable equilibrium positions, are used in a variety of applications, such as switches, clasps, and valves. Many kinds of compliant bistable mechanisms were proposed and studied during the past decade. Among them, tension-based compliant bistable mechanisms, that incorporate tension pivots as their flexible members, feature in short travel distance and low power consuming. So far, the design of this kind of bistable mechanisms is done using finite element method through trial and error, thus is time-consuming. By treating the tension pivots as fixed-guided segments and their elongation as a spring, we developed a novel three degree-of-freedom （3-DOF） pseudo-rigid-body model （PRBM） for this kind of bistable mechanisms. The principle of virtual work is used to derive the force-deflection relationship of the PRBM model. The comparison between the PRBM results and the experimental results of the force-deflection characteristics shows that the PRBM can predict not only the bistable behavior of the tension-based bistable mechanisms, but also their soft spring-like post-bistable behavior and the spring-like force-deflection characteristics when pulling in the reverse direction from the as-fabricated position, which is called reverse behavior. The 3-DOF PRBM can be used to design and identify tension-based bistable mechanisms. Using the PRBM instead of the trial-and-error method can greatly reduce the development time of this kind of bistable mechanisms.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3204800)the National Natural Science Foundation of China(Grant No.52375573)the Youth Innovation Team of Shanxi Universities(Grant No.2022-63)。
文摘This paper proposes an optimization method for finding the optimal design of a bistable mechanism with a desired performance that is robust to structural and material uncertainties.Using interval numbers to characterize the uncertainties in the structural parameters and materials,we present a nonprobabilistic multiobjective optimization model and transform it into a single objective optimization model using a penalty function.The sensitivity of the mechanical performance of bistable structures to uncertain parameters was analyzed,and the design parameters with notable effects on the bistable performance were identified as optimization variables.A neural network-based proxy model for the nonlinear characteristics of the bistable mechanism was established,and its accuracy was validated through finite element outcomes.Based on this model,a two-layer nested genetic algorithm was employed to solve the multiobjective robust optimization problem of the bistable structures with critical forces and a second stable position.The effectiveness of the optimization method was verified by comparing it with the finite element and experimental results.The proposed method was applied in the design of silicon-based inertial switches.
基金supported by National Natural Science Foundation of China(Grant No.50805110)Foundation for Key Program of Ministry of Education of China (Grant No.109145)Fundamental Research Funds for the Central Universities of China (Grant No.JY10000904010)
文摘Compliant bistable mechanisms, devices with two distinct stable equilibrium positions, are used in a variety of applications, such as switches, clasps, and valves. Many kinds of compliant bistable mechanisms were proposed and studied during the past decade. Among them, tension-based compliant bistable mechanisms, that incorporate tension pivots as their flexible members, feature in short travel distance and low power consuming. So far, the design of this kind of bistable mechanisms is done using finite element method through trial and error, thus is time-consuming. By treating the tension pivots as fixed-guided segments and their elongation as a spring, we developed a novel three degree-of-freedom （3-DOF） pseudo-rigid-body model （PRBM） for this kind of bistable mechanisms. The principle of virtual work is used to derive the force-deflection relationship of the PRBM model. The comparison between the PRBM results and the experimental results of the force-deflection characteristics shows that the PRBM can predict not only the bistable behavior of the tension-based bistable mechanisms, but also their soft spring-like post-bistable behavior and the spring-like force-deflection characteristics when pulling in the reverse direction from the as-fabricated position, which is called reverse behavior. The 3-DOF PRBM can be used to design and identify tension-based bistable mechanisms. Using the PRBM instead of the trial-and-error method can greatly reduce the development time of this kind of bistable mechanisms.
