Improved seal design based on minimizing strain energy

Abstract

Minimizing the strain energy in an oring seal has been identified as a mode of improving its useful lifetime. The intent of this research was to manipulate the strain energy content in oring seals by varying material properties and material behavior over the crosssection of the oring. Oring designs were developed that contained regions of modified material properties referred to as insets. These oring designs incorporating insets were evaluated numerically to determine the effects that the inset’s stiffness, size, and placement, had on the strain energy content and maximum sealing pressure of the oring design. Achievements included the development of oring designs that demonstrated lower strain energy content than a baseline design made of a single homogeneous material. Experimental orings were created using commercially available materials. Compression set and compression stress relaxation experiments were conducted. Performance of new oring designs including insets made of a softer material than the main oring was compared to baseline single material orings. Improved sealing performance was demonstrated by a decreased rate of sealing force decay over time, and by decreased compression set, for the new oring designs proposed.