Torque coefficients in automotive bolted joint assembly

Phuc Van Nguyen, Purdue University

Abstract

The thesis investigated the effects of four factors and their combinations on the torque coefficients of the first and second tightening of bolted joints by conducting a general full-factorial design with randomized blocks on 20 replications. The experiment involved three levels of tightening tool types, two levels of bolt dimensions, two levels of nut types, and two levels of plate type. The torque coefficients were calculated indirectly through the measuring the torque applied and bolt preload. The response variables studied were the mean and the variance between runs of the torque coefficients of the first tightening, as well as the ratio between the torque coefficients of the first and second tightening. The effects of the four factors and their combinations on the response variables were analyzed and reported. All main effects, three of the two-way interactions, one three-way interaction, and the four-way interaction were found to have statistically significant effects on the torque coefficients of the first tightening. The 24 combinations of the factors were found to have significant effects on the variance between runs of the torque coefficients of the first tightening.

Degree

M.S.

Advisors

Dunlap, Purdue University.

Subject Area

Mechanical engineering

COinS