Performance of reducing the dimensional error of an assembly by the rivet upsetting direction optimization

Abstract

Reduction in the dimensional error of an assembly mostly focuses on the variation of fixtures and parts inside, in which the variation is mainly controlled by the methods relating to the fixture design and variation analysis. Recently, more researches concentrate on the dimensional analysis of the aluminum assembly where the distortion of rivet joints cannot be neglected, that is, the riveting-induced dimensional error. Hence, both the device design and the variation analysis for the riveting are drawing much attention to reduce the overall distortion. This article presents a dimensional reduction method, a rivet upsetting direction optimization based on a local-to-global dimensional calculation. The method is developed from a recent framework of assembly process optimization according to the discovered sensitivity between global dimensional error and rivet upsetting directions. A potential function that gathers the overall effect of every locating error is included. Simulations for three riveted assemblies are presented for comparison and results show that the method is efficient for the specific assignment of every rivet upsetting directions, and the effects of locating errors and rivet upsetting directions are highly coupled. The coupled effect yields the key questions in the improvement of this method. Detailed suggestions are then summarized.

Assembly sequence optimization for minimizing the riveting path and overall dimensional error

“…Here, the AS is the order of the classifications of rivet joints. The preceding work 3 finds the optimal rivet UDs that relate to a less RMS and provides the preliminaries that support the further optimization for the efficiency and precision. The preliminaries comprise the expression of the assembly, the representation of the sequence, and the semantics of assembly logic.…”

“…Three riveted assemblies adhered from the previous work 3 are used to show the performance of AS optimization and open out more information about the assembly efficiency and precision by changing the process parameters and structural dimensions.…”

“…The input of rivet UDs are the optimized results of the preceding work, 3 which is shown in Figure 5. The n by n blocks denote the UDs of rivets where each block takes the black or white color that implies the positive or negative direction of the axis in the coordinate system of the assembly.…”

“…2 The rivet UD optimization is studied for the first step and results show the degree of optimization in RMS under the variations of influence factors. 3 The AS can lift the RMS by about 0.26 mm for the assembly with 1093 rivets. And a different AS has a different length of riveting path.…”

Residual stress and fatigue behavior of riveted lap joints with various riveting sequences, rivet patterns, and pitches

“…The riveted lap joint is one of the most common failure sources in the aircraft. 1,2 The riveted structure, used in the modern commercial aircraft, is subjected to the loading from pressurization of fuselage. The ground-air-ground pressurization cycle loads provide one major cycle of fatigue loading on the riveted structure in the airframe.…”