Three-dimensional moisture diffusion simulation with time dependent saturated concentration in ANSYS through native thermal and spring elements
Abstract This study presents a new modeling approach for moisture concentration in the presence of time dependent saturated moisture concentration and diffusivity by considering only native ANSYS elements. It removes the shortcomings of the ANSYS “diffusion” and “coupled field” elements by employing thermal (LINK33, PLANE55 and SOLID70) and spring (COMBIN14) elements. The accuracy of this modeling approach is established by demonstrating desorption and absorption process in a bar made of two different materials with equal and unequal values of solubility activation energy in the presence of time dependent saturated moisture concentration under uniform and nonuniform temperature conditions. Also, it is applied to a representative three-dimensional electronic package configuration to demonstrate the effect of time dependent saturated moisture concentration on moisture diffusion and weight gain.