Methodology for clamping load measurement of locking systems based on white light digitalization

• A new method to measure clamping load of locking elements based on white light digitalization has been developed.
• The relationship between clips elongation and load applied is linear.
• There is not any direct relationship between clip stiffness and load performed.
• Initial length has a great influence on the final load performed.
• Attention must be paid to tolerances for high stiffness clips to assure proper clamping force.

This paper presents a new methodology to measure clamping force of locking clips of a weatherproof luminary from the previous determination of its stiffness and the elongation they suffer under assembly conditions. Application of the methodology includes determination of the clip stiffness both experimentally and by FEM analysis, and measurement of the elongation by structured white light digitalization techniques.Elongation values measured by white light are similar to those analyzed by conventional methods. The relationship between clips elongation and load applied is linear, so stiffness can be deduced from the slope of the curve. Results show that functionality of the clips can be achieved with different values of stiffness. There is not any direct relationship between clip stiffness and load performed by them because of the influence of initial length on the final load performed. Therefore, manufacturing tolerances must be taken into account to assure the proper performance of the clips.