Application of glass fi lled thermoplastics for design of low/high temperature signal conditioning devices

摘要

A 3D finite element based computational model is presented to study thermal deformations occurring in both isotropic and ortho-tropic radio frequency (RF) signal conditioning devices exposed to varying temperature conditions. The model captures the effect of elastic behavior with inherent orthotropy. In modeling orthotropy, the flow and cross-flow directions are chosen based on results from a mold flow analysis that indicate the fiber orientations. The orientations of fibers are identified and new orientations are additionally assigned to various regions in the model. The material properties are specified for flow and the cross-flow directions of ULTEM~®, a GE Plastics material. Thermal deformations are obtained both numerically as well as experimentally when the device is exposed to temperatures between -40 ℃ and 125 ℃. The effect of fiber orientation is found to influence the deformation state in the flow and cross-flow directions for the RF signal conditioning device made of ULTEM~®. The model was shown to be effective in indicating changes in deformation and is expected to have significant potential for metal replacement in signal conditioning devices and similar structural systems in the field.