Analysis, formulation, and optimisation of the strain concentration factor in double countersunk holes due to uniaxial tension

ABSTRACT

Finite element and response surface methods were utilised to investigate the strain concentration factor-induced in isotropic rectangular plates with two identical countersunk rivet holes due to uniaxial tension. Besides, a simple and precise formula to compute the strain concentration factor (SεCF) is developed. In this investigation, the finite element model was constructed using ANSYS software and used to produce (SεCF) data. Additionally, the response surface method (RSM) was implemented to examine the influence of the problem geometric and material parameters on the SεCF. RSM combined with least square regression methods were engaged to formulate a simple and effective equation to mathematically compute stress concertation factor ($K_{t,\text{isin}}$) value. This equation was consequently verified with finite element analysis (FEA) results. Lastly, an optimum plate and hole configuration than minimises the SεCF was suggested and hence recommended.

KEYWORDS:

• Double countersunk holes
• strain concentration factor
• finite element method
• response surface method
• uniaxial tension

Nomenclature

b	=	Straight shank thickness
Cs	=	Countersink depth
E, v	=	Modulus of Elasticity and Poisson’s ratio
FEA	=	Finite element analysis
Kt, ∈	=	Strain concentration factor
L	=	Plate half-length
r	=	Straight shank radius
RSM	=	Response surface methodology
SCF	=	Stress concentration factor
SεCF	=	Strain concentration factor
t	=	Plate thickness
w	=	Plate half-width
wh	=	Half the separating distance between the centers of the countersunk holes
x,y,z	=	CARTESIAN coordinate system
θc	=	Countersink angle
λ	=	Normalized separating distance between the countersunk holes

Disclosure statement

No, potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the Hashemite University [2020].

Notes on contributors

Mohammad A. Gharaibeh

Mohammad A Gharaibeh holds B.Sc. and M.Sc. degrees in manufacturing and mechanical engineering from Jordan University of Science and Technology in 2009 and 2011, respectively. In 2015, he received his PhD degree in mechanical engineering from State University of New York at Binghamton, NY, USA. Currently he is an assistant professor in the mechanical engineering department at the Hashemite University, Jordan. His research interests are directed towards solid and computational mechanics.