In engineering terms, the material used would need to be able to accept the limit load with elastic deformation for "infinite" cycles, and if I understand you correctly Brian, would also show that it will resist plastic deformation at the ultimate load for three seconds. Or is the spec written to require that the material resists failure/fracture for three seconds at that load/energy level?
Last edited by Lonewolf_50; 15th Mar 2013 at 12:33.