ABSTRACT
One aspect of the model is crucial and needs emphasis. The shaft has a bending stiffness such as is measured in the standard cantilever bending test. However during the swing, particularly near impact when the centripetal forces are large, the shaft also acquires an additional bending stiffness due to the fact that the shaft is under considerable tension. This type of stiffness is analogous to that of a stretched string which will resist lateral displacement. In a full drive or similar distance shot this “tension bending stiffness” is, in the 30ms or so before impact, large enough to be comparable to the conventional bending stiffness.
