in this fashion to avoid artifacts from the ends of the jounce bumper the zero mm reference point was an external point located on the plate of the compression machine the molded parts were conditioned by applying 3 compression cycles from 0 to 10kn at 50 mm min at 23 u00b0 c the parts were then released and maintained for one hour at a temperature of 23 u00b0 c without stress the molded parts were then exposed to a fourth compression cycle using the same conditions as the first three cycles this last cycle defined the static compression curve of the jounce bumpers table 2 lists force required to give 50 relative deformation f50 force required to give 60 relative deformation f60 and relative deformation at the application of 10kn force x10kn it is clear that the force required to cause 50 relative deformation of the jounce bumpers according to the invention i e e1 and e2 which have tc tm of 1 62 and 2 03 respectively is substantially higher 603 n and 775 n respectively than the force required to cause 50 relative deformation in the comparative jounce bumper c1 which has tc tm of 1 15 529 n this is also true at 60 relative deformation jounce bumpers e1 and e2 require forces of 1117 n and 1362 n to.