| Inertial device is the core component of inertial navigation and guidance system,its performance directly determines the navigation and guidance accuracy of the system,and the performance of inertial device is closely related to the assembly process.In the assembly and connection of the core structure of the inertial device,epoxy adhesives with excellent mechanical properties,high temperature resistance,corrosion resistance,and the ability to connect heterogeneous materials are used in many places.Since the epoxy adhesive used is a thermosetting polymer material,it will produce physical shrinkage and chemical shrinkage during the curing process,which will change its own volume and cause the core structure of the inertial device to generate curing residual stress,which seriously affects the product qualification rate and performance stability.Relevant studies show that the curing residual stress produced by different curing processes is quite different.Therefore,it is of great engineering significance and value in the field of inertial devices to accurately measure the residual stress introduced by the epoxy adhesive during the curing process and optimize the curing process of the epoxy adhesive.This paper takes the epoxy adhesive for photoelectric inertial devices as the research object.First,the structure and working principle of the photoelectric inertial device are described in detail,and the output phenomenon of the photoelectric inertial device is expounded and analyzed.According to the experimental and simulation results,the curing residual stress of the epoxy adhesive is large,and the residual stress needs to be reduced by optimizing the curing process.Secondly,the theoretical method of studying the curing process is introduced.According to the theoretical method and related experiments,the curing kinetic equation and theoretical curing process of epoxy adhesive are obtained.Finally,the curing process of epoxy adhesive is decomposed into temperature field and stress-strain field,ABAQUS user material subprograms with corresponding field variables are written,and the temperature field of curing process of epoxy adhesive for photoelectric inertial devices is numerically simulated.The main work contents are as follows:(1)Based on the structure and working principle of the photoelectric inertial device,a simplified block diagram of the output is established,the mathematical expression of the output is deduced,and the output instability,non-repetition and zero drift of the photoelectric inertial device are analyzed.A positive experiment and simulation study on the current epoxy adhesive for optoelectronic inertial devices and its bonding structure are carried out.The research results show that the curing residual stress of the epoxy adhesive is large,and the curing process parameters need to be studied to reduce the curing residual stress.(2)Based on non-isothermal/isothermal DSC experiments,the curing kinetic equation of epoxy adhesive for optoelectronic inertial devices was studied.The curing kinetic equation of each exothermic peak was deduced by the method of split-peak fitting,and then the curing kinetic equation of the epoxy adhesive was obtained according to the proportion of exothermic heat,and the accuracy of the equation was verified by experiments.The theoretical curing process of the epoxy adhesive was obtained by the method.(3)The curing exotherm and curing shrinkage of epoxy adhesive were studied,and the heat conduction equation,exothermic equation,curing constitutive model and curing strain mathematical model of epoxy adhesive were established.Based on ABAQUS software,several user material subprograms such as HETVAL and SDVINI were written,and the temperature field model and stress-strain field model of epoxy adhesive were constructed.The influence of the internal temperature gradient of the adhesive layer on the thermal stress of the adhesive layer. |
