Reflector ray machine adjustment prediction method based on glue spot thermal simulation assistance

Abstract

The invention provides a reflector light machine installation and adjustment prediction method based on glue spot thermal simulation assistance, relates to the technical field of light machine installation and adjustment, and aims to optimize a glue joint process route according to a finite element simulation result by performing finite element modeling on a reflector, a reflector base and glue spots and analyzing stress distribution of the reflector after glue joint. And the technical difficulty of high-strength and low-stress glue joint of the large-size reflecting mirror is solved.

Description

Technical Field

[0001] The invention relates to the technical field of optical-mechanical assembly and adjustment, and in particular provides an optical-mechanical assembly and adjustment prediction method for a reflector based on the assistance of adhesive spot thermal simulation. Background Art

[0002] In precision optical machine products, beam splitters, reflectors and other reflectors are mostly fixed by structural adhesive bonding, such as Figure 3 As shown. Structural adhesive is a kind of silicone rubber with a certain elasticity, which can play the role of bonding, fixing and protecting the reflector in a specific temperature (-55℃-70℃) and vibration environment. However, the stress generated by the structural adhesive during the curing process due to its own shrinkage will act on the reflector and the metal mirror seat, causing the parts to deform and the reflector surface to deteriorate, ultimately leading to a decrease in the imaging quality of the optical system.

[0003] Therefore, it is necessary to provide a reflector optical-mechanical assembly method to ensure that the reflector is subjected to minimal stress without debonding after assembly. Summary of the invention

[0004] The purpose of this application is to provide a method for predicting the optical-mechanical assembly of a reflector based on thermal simulation of glue spots. By performing finite element modeling on the reflector, mirror seat, and glue spots, the stress distribution of the reflector after bonding is analyzed, and based on the finite element simulation results, the bonding process route is optimized, thereby solving the technical difficulties of high-strength and low-stress bonding of large-size reflectors.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for predicting optical-mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance, the method comprising:

[0007] S1: Establish a three-dimensional model of the reflector, mirror base and adhesive spot, and then import the three-dimensional model into the finite element analysis software;

[0008] S2: Process the structural features of the threaded holes on the frame;

[0009] S3: Setting the material properties, connection relationships and constraints of the reflector, mirror base and adhesive spot;

[0010] S4: Use full hexahedral solid elements to mesh the reflector, mirror base and adhesive spot respectively;

[0011] S5: Setting thermal simulation conditions;

[0012] S6: Run the finite element analysis software to obtain the deformation result of the mirror surface;

[0013] S7: calculating the absolute value of the change in the deformation of the mirror surface of the reflector after removing the rigid body displacement according to the deformation result of the mirror surface of the reflector, where the absolute value of the change includes the mean value PV of the change and the root mean square value RMS of the change;

[0014] S8: setting the initial range of the adhesive spot thickness T and the adhesive spot length L, taking the adhesive spot thickness T and the adhesive spot length L as variables, taking the minimum PV value, the minimum maximum normal stress and the maximum shear stress of the bonding interface as the optimization target, solving the reflection mirror surface type result and the maximum normal stress and the maximum shear stress of the bonding interface, and obtaining a simulation data set, wherein the simulation data set includes a plurality of parameter groups, each parameter group includes the corresponding adhesive spot thickness, adhesive spot length, PV value, maximum normal stress and maximum shear stress;

[0015] S9: Select the parameter group whose maximum normal stress and maximum shear stress simultaneously meet the result requirements in the simulation data set. If only one parameter group meets the result requirements, then this group of data is the optimal solution for the adhesive patch. If multiple parameter groups meet the result requirements, then the adhesive patch thickness and adhesive patch length parameters in multiple parameter groups are used as the initial range, and return to S1 for iterative calculation.

[0016] The optical-mechanical adjustment prediction method of a reflector based on adhesive spot thermal simulation assistance provided by the present invention also has the following characteristics:

[0017] The material properties include density, elastic modulus, Poisson's ratio, and equivalent linear expansion coefficient;

[0018] The connection relationship includes frictionless contact between the bottom surface of the reflector and the mirror base, inseparable binding contact between the reflector and the adhesive spot, and inseparable binding contact between the mirror base and the adhesive spot;

[0019] The constraint conditions include full constraints on the mirror base and the external mounting surfaces and mounting holes.

[0020] The method for predicting optical-mechanical adjustment of a reflector based on thermal simulation of a glue spot provided by the present invention also has the following characteristics: the steps for determining the equivalent linear expansion coefficient of the glue spot are as follows:

[0021] The silicone rubber was tested. Under laboratory conditions, the volume V2 of the liquid silicone rubber after curing was measured per unit volume V1, and the volume shrinkage rate of the adhesive spot during curing was obtained as follows:

[0022]

[0023] The curing shrinkage rate of the adhesive spot from liquid to solid is converted into the equivalent linear expansion coefficient of the adhesive spot. Assuming that the adhesive spot is an isotropic thermal conductor, the equivalent linear expansion coefficient of the adhesive spot is:

[0024]

[0025] The method for predicting optical-mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance provided by the present invention also has the following feature: in S4, the grid is divided into at least three layers of units in the adhesive layer thickness direction.

[0026] The method for predicting optical-mechanical assembly of a reflector based on adhesive spot thermal simulation assistance provided by the present invention also has the following characteristics: the setting of thermal simulation conditions includes thermal simulation load and vibration conditions, and the determination of thermal simulation load and vibration conditions includes:

[0027] Set the thermal expansion coefficient of the reflector and the mirror holder to 0, set the thermal expansion coefficient of the adhesive spot to the linear shrinkage rate, and apply a uniform cooling load of -1 degree to the assembly;

[0028] The assembly is set under gravity, and the boundary conditions are that the normal stress and shear stress values ​​should be lower than the peeling force under 3sigma vibration conditions.

[0029] Beneficial Effects

[0030] The method provided by the present invention establishes a finite element analysis model of the reflector component, establishes an optomechanical structure model of the reflector, mirror frame and glue spot by using finite element software, performs static analysis on the reflector bonding process, performs thermal simulation analysis on the glue spot curing shrinkage process, and performs trial and error optimization on parameters such as glue spot position, glue spot area, and glue spot thickness, thereby reducing bonding stress and optimizing the reflector assembly method. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A flowchart of a method provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of grid division in the method provided in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the reflector optical machine assembly. DETAILED DESCRIPTION

[0035] The present application is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation methods are not limitations of the present application, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation methods are all within the scope of protection of the present application.

[0036] In the description of the embodiments of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the creation of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the creation of the present application.

[0037] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0038] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of this application can be understood by specific circumstances.

[0039] like Figure 1-2 As shown, the embodiment of the present application provides a method for predicting optical-mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance, the method comprising:

[0040] S1: Establish a three-dimensional model of the reflector 1, the mirror base 2 and the adhesive spot 3, and then import the three-dimensional model into the finite element analysis software;

[0041] S2: Processing the structural features of the threaded holes on the mirror frame; the processing of the structural features includes processing of threads and chamfers, but does not include processing of the contact surfaces between the reflector, the mirror frame and the adhesive spot;

[0042] S3: setting the material properties, connection relationship and constraint conditions of the reflector 1, the mirror base 2 and the adhesive spot 3;

[0043] S4: Use full hexahedral solid units to mesh the reflector 1, the mirror base 2 and the adhesive spot 3 respectively;

[0044] S5: Setting thermal simulation conditions, setting the equivalent linear expansion coefficient of the adhesive spot 3 to the linear contraction rate, setting the linear expansion coefficients of other components to zero, and then applying a uniform temperature drop load to the entire assembly;

[0045] S6: Run the finite element analysis software to obtain the deformation result of the mirror surface of the reflector 1;

[0046] S7: calculating the absolute value of the change in the deformation of the mirror surface of reflector 1 after removing the rigid body displacement according to the deformation result of the mirror surface of reflector 1, where the absolute value of the change includes the mean value PV and the root mean square value RMS of the change;

[0047] S8: setting the initial range of the thickness T of the adhesive spot 3 and the length L of the adhesive spot 3, taking the thickness T of the adhesive spot 3 and the length L of the adhesive spot 3 as variables, taking the minimum PV value and the minimum maximum normal stress and maximum shear stress of the bonding interface as optimization targets, solving the surface result of the reflector 1 and the maximum normal stress and maximum shear stress of the bonding interface, and obtaining a simulation data set, wherein the simulation data set includes multiple parameter groups, each parameter group includes the corresponding adhesive spot thickness, adhesive spot length, PV value, maximum normal stress and maximum shear stress;

[0048] S9: Select the parameter group whose maximum normal stress and maximum shear stress simultaneously meet the result requirements in the simulation data set. If only one parameter group meets the result requirements, then this group of data is the optimal solution for the adhesive patch. If multiple parameter groups meet the result requirements, then the adhesive patch thickness and adhesive patch length parameters in multiple parameter groups are used as the initial range, and return to S1 for iterative calculation.

[0049] In the above embodiment, a simulation method is used to simulate the model of mirror glue filling under different glue spot parameters, so as to reduce the strain of the mirror surface as the optimization goal, and the software is used to solve the mirror surface shape under various working conditions, and then the process parameters are iteratively optimized according to the changes in the mirror surface shape, thereby shortening the time of traditional multiple experimental operations and reducing the number of trial and error.

[0050] In some embodiments, the material properties include density, elastic modulus, Poisson's ratio, and equivalent linear expansion coefficient;

[0051] The connection relationship includes frictionless contact between the bottom surface of the reflector and the mirror base, inseparable binding contact between the reflector and the adhesive spot, and inseparable binding contact between the mirror base and the adhesive spot;

[0052] The constraint conditions include full constraints on the mirror base and the external mounting surfaces and mounting holes.

[0053] Since the reflector is directly placed on the mirror base and fixed together by adhesive bonding, the reflector and the mirror base are set to frictionless contact. In the analysis, it is believed that the adhesive bonding is relatively reliable, so the reflector and the adhesive bonding, and the reflector base and the adhesive bonding are set to binding contact.

[0054] In some embodiments, the steps for determining the equivalent linear expansion coefficient of the adhesive spot are as follows:

[0055] The silicone rubber was tested. Under laboratory conditions, the volume V2 of the liquid silicone rubber after curing was measured per unit volume V1, and the volume shrinkage rate of the adhesive spot during curing was obtained as follows:

[0056]

[0057] The curing shrinkage rate of the adhesive spot from liquid to solid is converted into the equivalent linear expansion coefficient of the adhesive spot. Assuming that the adhesive spot is an isotropic thermal conductor, the equivalent linear expansion coefficient of the adhesive spot is:

[0058]

[0059] In some embodiments, in S4, the grid is divided into at least three layers of units in the direction of the glue layer thickness.

[0060] In some embodiments, the setting of the thermal simulation conditions includes a thermal simulation load and a vibration condition, and the determining of the thermal simulation load and the vibration condition includes:

[0061] Set the thermal expansion coefficient of the reflector and the mirror holder to 0, set the thermal expansion coefficient of the adhesive spot to the linear shrinkage rate, and apply a uniform cooling load of -1 degree to the assembly;

[0062] The assembly is set under gravity, and the boundary conditions are that the normal stress and shear stress values ​​should be lower than the peeling force under 3sigma vibration conditions.

[0063] The curing shrinkage simulation of the reflector assembly adopts a linear analysis method, so the material data of each part in the calculation adopts the linear property part, including elastic modulus, Poisson's ratio, density and equivalent linear expansion coefficient. The specific material properties are shown in Table 1:

[0064] Table 1 Material data for curing shrinkage simulation analysis of reflector components

[0065]

[0066] Among the parameters of the adhesive spot, the shrinkage rate obtained from the experimental test refers to the volume shrinkage rate, not the linear shrinkage rate, so it is necessary to convert the volume shrinkage rate of the adhesive spot into the equivalent linear expansion coefficient of the adhesive spot. Assuming that the equivalent linear expansion coefficient of the adhesive spot is β and the volume shrinkage rate is α, the conversion formula can be obtained according to the definition of the linear expansion coefficient as follows:

[0067]

[0068] The volume shrinkage of the adhesive spot obtained from the test is 0.19%, so the equivalent linear expansion coefficient of the adhesive spot can be calculated to be 0.000633735. Since the reflector and the mirror seat will not shrink during curing, the equivalent linear expansion coefficient of the reflector and the mirror seat is set to 0 in the analysis.

[0069] In some embodiments, the iterative optimization process of the adhesive spot process parameters comprises the following steps:

[0070] a) Import the deformation results of the reflector surface calculated by the simulation software into the MATLAB software, and calculate the absolute value of the change in the deformation of the reflector surface after removing the rigid body displacement, that is, the PV value and RMS value of the reflector surface, where the PV value is the mean value of the deformation and the RMS value is the root mean square value of the deformation;

[0071] b) parameterizing the thickness T and length L of the adhesive spot, with the thickness T varying in the range of 0.5 to 1.5 mm and the length L varying in the range of 8 to 15 mm. For the two variables T and L, each variable takes no less than three values ​​to obtain a variety of combined parameter solutions;

[0072] c) Taking the minimum PV value and the minimum maximum normal stress and maximum shear stress of the bonding interface as the optimization goals, the reflective mirror surface type results and the maximum normal stress and maximum shear stress of the bonding interface are solved, as shown in Table 2;

[0073] d) Select the optimal solution interval from the results, and then perform iterative calculations until the optimal solution is obtained.

[0074] Table 2 Simulation results analysis

[0075]

[0076]

[0077] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for predicting optical and mechanical adjustment of a reflector based on thermal simulation of adhesive spots, characterized in that: The method comprises: S1: Establish a three-dimensional model of the reflector, mirror base and adhesive spot, and then import the three-dimensional model into the finite element analysis software; S2: Process the structural features of the threaded holes on the frame; S3: Setting the material properties, connection relationships and constraints of the reflector, mirror base and adhesive spot; S4: Use full hexahedral solid elements to mesh the reflector, mirror base and adhesive spot respectively; S5: Setting thermal simulation conditions; S6: Run the finite element analysis software to obtain the deformation result of the mirror surface; S7: calculating the absolute value of the change in the deformation of the mirror surface of the reflector after removing the rigid body displacement according to the deformation result of the mirror surface of the reflector, where the absolute value of the change includes the mean value PV of the change and the root mean square value RMS of the change; S8: setting the initial range of the adhesive spot thickness T and the adhesive spot length L, taking the adhesive spot thickness T and the adhesive spot length L as variables, taking the minimum PV value, the minimum maximum normal stress and the maximum shear stress of the bonding interface as the optimization target, solving the reflection mirror surface type result and the maximum normal stress and the maximum shear stress of the bonding interface, and obtaining a simulation data set, wherein the simulation data set includes a plurality of parameter groups, each parameter group includes the corresponding adhesive spot thickness, adhesive spot length, PV value, maximum normal stress and maximum shear stress; S9: Select the parameter group whose maximum normal stress and maximum shear stress simultaneously meet the result requirements in the simulation data set. If only one parameter group meets the result requirements, then this group of data is the optimal solution for the adhesive patch. If multiple parameter groups meet the result requirements, then the adhesive patch thickness and adhesive patch length parameters in multiple parameter groups are used as the initial range, and return to S1 for iterative calculation.

2. The method for predicting optical and mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance according to claim 1 is characterized in that: The material properties include density, elastic modulus, Poisson's ratio, and equivalent linear expansion coefficient; The connection relationship includes frictionless contact between the bottom surface of the reflector and the mirror base, inseparable binding contact between the reflector and the adhesive spot, and inseparable binding contact between the mirror base and the adhesive spot; The constraint conditions include full constraints on the mirror base and the external mounting surfaces and mounting holes.

3. The method for predicting optical and mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance according to claim 2 is characterized in that: The steps to determine the equivalent linear expansion coefficient of the adhesive spot are as follows: The silicone rubber was tested. Under laboratory conditions, the volume V2 of the liquid silicone rubber after curing was measured per unit volume V1, and the volume shrinkage rate of the adhesive spot during curing was obtained as follows: The curing shrinkage rate of the adhesive spot from liquid to solid is converted into the equivalent linear expansion coefficient of the adhesive spot. Assuming that the adhesive spot is an isotropic thermal conductor, the equivalent linear expansion coefficient of the adhesive spot is:

4. The method for predicting optical and mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance according to claim 1, characterized in that: In the above S4, when dividing the grid, there are no less than three layers of units in the direction of the glue layer thickness.

5. The method for predicting optical and mechanical adjustment of a reflector based on adhesive spot thermal simulation assistance according to claim 1, characterized in that: The setting of the thermal simulation conditions includes thermal simulation load and vibration conditions, and the determining of the thermal simulation load and vibration conditions includes: Set the thermal expansion coefficient of the reflector and the mirror holder to 0, set the thermal expansion coefficient of the adhesive spot to the linear shrinkage rate, and apply a uniform cooling load of -1 degree to the assembly; The assembly is set under gravity, and the boundary conditions are that the normal stress and shear stress values ​​should be lower than the peeling force under 3 sigma vibration conditions.

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