Research On Testing Method Of Thermophysical Properties Of Multilayer Composites

With the development of technology,multi-layer composites have been widely used in different industries due to the ability of combining the advantages of different materials,but there is no corresponding test reference standard at present.In this paper,a new testing method is proposed for multi-layer materials according to the emerging application scenarios in the industry.The research work on the characterization of thermal physical parameters of multi-layer materials,aiming at realizing and optimizing test algorithm and put it into practice.The main research contents of this paper include: Implementing the algorithm of structure function,Computer simulation and Software and Hardware research of test device.Structural function is a nondestructive testing method for thermal resistance measurement of semiconductor electronic packaging.It can deduce integral structure function and differential structure function,which contain the characterizing of thermal resistance and heat capacity,according to transient temperature response curve.Obviously,structural function is not only applicable to semiconductor,but also to thermal testing of materials.The material is regarded as a series combination of multiple thermal resistances and heat capacities,i.e.the standard RC circuit superposition.The networks are FOSTER network model and CAUER network model respectively,and they can be converted to each other.As we all know that the thermal response transfer function of the system is constant,so the whole testing process is similar to system identification.We need to determine the mathematical model describing the system behavior according to the input and output time function of the system.The basic function of structural function method is realized by computer simulation and the test software is designed based on MATLAB.Finally,the algorithm is optimized with experimental tests to increase its robustness and the results will lay a foundation for the development of practical industrial applications.This paper designed the software based on the structural function method and the experimental platform was set up to verify the feasibility and effectiveness of the program.Besides,the feasibility of the algorithm is verified and the related codes are attached.Through the analysis of uncertainty and error sources,the test algorithm is optimized by adding data smoothing steps,and the test accuracy and test stability are improved.