What type of force can cause fasteners to fail in a clearance fit much faster than the same fastener would fail in a transition or interference fit?

In the context of fasteners and their interactions with materials, shear force is critical. Shear force acts parallel to the area of connection between the fastener and the components it joins. In a clearance fit, there is more relative motion between the fastener and the components, meaning that the fastener is more susceptible to being loaded with shear forces.

When a fastener is in a clearance fit, it allows movement between the parts, which can lead to increased shear stress on the fastener during loading and unloading cycles. This repeated shear loading can contribute to fatigue failure at a much higher rate compared to a fastener that is in a transition or interference fit, where there is a tighter grip and less opportunity for relative movement.

In summary, shear forces in a clearance fit can lead to a quicker failure of fasteners due to the cyclic loading that promotes material fatigue. This understanding is essential for correctly assessing the longevity and reliability of fasteners used in aerospace applications.