EJMA design equations part 2

摘要

The Standards of the Expansion Joint Manufacturers Association (EJMA) are widely referenced for the design and application of round and rectangular metal expansion joints. The recent 7~th edition incorporates several important changes. The design equations for bellows instability have been modified to consider the effects of both biaxial stress and initial angular rotation. An appendix has been added for the evaluation of high temperature cycle life. Other changes are planned for the next addenda which include revised limits for the S3 + S4 stress, new equations for angular rotation about one end, modifications to consider the effect of extension movement on the S2 stress, and additions to treat the effects of pressure on angular movement. This paper is written to provide the background and theoretical basis for these changes.