A numerical study on the triaxiality distribution in a single shear lap fastener joint
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Issue Date
2017-12
Authors
De Abreu Barriga, Armando A.
Advisor
Keshavanarayana, Suresh R.
Citation
Abstract
Fastened joints are used extensively in the aerospace industry and play an important role
in defining the crashworthiness of the structure [1, 2]. As larger finite element models (FEM) are
developed, joints are typically simplified as a way to obtain computational time savings.
However, these simplification need to be able to account for complex failure criteria, such as
triaxiality and Lode parameter dependent failure criteria.
In the current study, a single shear lap fastener joint is studied to identify the effects that
the coefficient of friction (0 to 1), preload (0 to 2300 N), and fastener fit (interference and
clearance) have on the triaxiality distribution of the joint. A series of finite element analysis
(FEA) was carried out in LS-DYNA [3] to quantify the effects of said parameters
Higher friction correlated to increases in triaxiality peaks of up to 50% in certain areas of
the joint. Variations in preload also affected the triaxiality distribution but only in the low remote
stress regime (<250 MPa). Fastener fit also had a major effect on the triaxiality distribution of
the joint.
Overall, regions of the joint prone to fretting fatigue tended to have high triaxiality peaks
at low remote stress. The analysis showed that identifying the operational load range is essential
when analyzing joints and determining the appropriate failure criteria to be used in the FEA.
Additionally, some simplifications to joints can be made as long as the user is aware of the
consequences such simplifications has on parameters such as load transfer, and triaxiality.
Table of Content
Description
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering