The Junker vibration test meeting DIN 65151 (Dynamic testing of the locking characteristics of fasteners under transverse loading conditions – vibration test) standards is a common and reliable method for testing and comparing the security of bolted joints.
The Junker’s transverse vibration-loosening test provides a simplified method for broad scale testing and inspection of the transverse vibration (loosening) properties of fasteners. The test machine is able to generate relative motion in the clamped parts perpendicular to the axis of the fasteners.The Junkers method provides quantitative results relating the variables of clamp-load, number of cycles, and amplitude.
The Junkers test is considered a ‘severe’ test of the loosening characteristics of fasteners, particularly when compared to previously introduced test methods which rely on axial dynamic loading to induce loosening. Junker largely established the viability of the current method in a paper entitled Investigations of the Mechanism of Self-Loosening and Optimal Locking of Bolted Connections.