Abstract
Single-component thermal conductive silica gel (S-TCSG) is a new type of thermal conductive material for packaging electronic components in high-performance printed circuit boards. Its mechanical properties can lead to excessive deformation of printed circuit boards or even solder joint fracture during screw fastening or falling. In this paper, an experimental program was developed to study the mechanical properties of the S-TCSG, such as cushioning property, creep and stress relaxation. The relationship model is established between cushioning coefficient, compression stress and compression strain on the basis of the compression stress-strain test. In addition, the time-varying laws of the compression creep and stress relaxation of the S-TCSG were studied experimentally. The elastic modulus, relaxation modulus and creep compliance can be obtained based on the experimental data. A nonlinear finite element model (FEM) of the S-TCSG is established. Furthermore, the influence of gel thickness on stress distribution is analyzed in screw tightening. A mathematical model is proposed to characterize the relationship between gel thickness, compressive stress and displacement load. This study is of great practical significance to the rationality of coating thickness of the S-TCSG and the performance improvement of printed circuit boards.