Contact behavior analysis of X-ring under internal pressure and uniform squeeze rate using photoelastic experimental hybrid method

Abstract

X-rings were introduced as a result of the limitations of O-rings that twist, especially during dynamic applications. The X-ring design avoids twisting, and the presence of a groove between the lobes acts as a lubricant reservoir that improves the packing life of these seals. Because of the multiple seal points, less squeeze rate is required to provide an effective seal. In addition, friction and wear is decreased, which increases seal life and decreases maintenance costs. Therefore, a better understanding of the behavior and stress distribution of X-rings under a loading condition of uniform squeeze rate and internal pressure is necessary. However, most research to date has been done on the O-ring. We focused on analysis of contact length and contact stresses developed in X-rings under a uniform squeeze rate of 20% (which is suitable for static applications) using a photoelastic experimental hybrid method, and ascertained the packing ability of the X-ring. We show that sealing rings with the X geometry have considerably higher contact stresses than O-ring seals. Also, the contact stresses were higher than the internal stresses of the X-ring. Therefore, our analysis of the contact stresses is adequate in establishing the behavior of the X-ring.