Structural Reliability Sensitivity And Reliability Robust Design For Compliant Mechanism

With the widespread application of compliant mechanisms in high-precision areas such as precision measurement,micro-positioning platforms,communications engineering,and optical engineering,while the demand for flexible mechanisms has been expanding,the number of problems in structural reliability has increased.It attracted the attention of researchers and engineers in compliant institutions.At present,in the course of research on the structural reliability of flexible mechanisms,the following three problems are also faced: First,due to the complex structure of flexible mechanisms and numerous design variables,it is difficult to determine the relationship between variables and function functions;second is the compliance mechanism.Due to the interference of factors such as materials,processes,personnel,and the environment,the value of design variables fluctuates,making it difficult to determine the structural reliability and sensitivity,and it is impossible to scientifically evaluate the quality characteristics of flexible mechanisms.Third,it is difficult to improve.The structural reliability and robustness of the compliance mechanism.In view of the above three problems,this paper takes the round straight beam type flexible hinge as the research object,and proposes the reliability sensitivity design and reliability robust design method for the complex structure of the compliant mechanism.The main work is as follows:Firstly,The relationship between the design variable and the response target of the flexible hinge is a hidden problem.The approximate model is constructed by combining the response surface method with the finite element simulation.First,the working principle of the flexible hinge is analyzed to determine the design variables that have significant influence on the reliability of the flexible hinge.Secondly,the test is arranged through the response surface experimental design method.The finite element simulation technology is used to obtain the test results to obtain the required model for the flexible hinge.Data;The approximate model of the flexible hinge is constructed by the response surface method;Finally,the accuracy test is performed to determine the design variables and the maximum stress model of the flexible hinge.Secondly,In order to solve the difficult problem of reliability and reliability sensitivity of compliant mechanism,the performance function of flexible hinge is constructed based on the stress-strength interference theory.Based on this,the center point method is used for reliability and sensitivity design to ensure the accuracy of the results.Comparing the verification point method with the Monte Carlo method respectively,the results show that the results of the three methods are basically the same,indicating the correctness of the reliability and sensitivity design.Finally,For the problem that the reliability of the compliant mechanism is difficult to meet the actual needs of the project,the flexible hinge is designed for reliability and robustness.The reliability robust design model of flexible hinge is constructed.The reliability of the flexible hinge and the boundary of the design variables are taken as constraints,and the quality and reliability sensitivity of the flexible hinge are taken as the objective function to make the value of the objective function as small as possible.The method effectively reduces the sensitivity of design variables to reliability.While the reliability meets the requirements of the project,the flexibility of the flexible hinge against the fluctuation of the design variables is improved and the performance is more robust.