Question

Which of the following is the correct expression for calculating skew of quadrilateral element?

(a) Skew=90°+minimum angle formed by joining opposite mid sides of quad element

(b) Skew=90°-minimum angle formed by joining opposite mid sides of quad element

(c) Skew=90°*minimum angle formed by joining opposite mid sides of quad element

(d) Skew=90°/minimum angle formed by joining opposite mid sides of quad element

I had been asked this question in an interview.

My doubt is from Conjugate Gradient Implementation of Quadrilateral Element topic in division Two Dimensional Isoparametric Elements and Numerical Integration of Finite Element Method

Answer 1

Right answer is (b) Skew=90°-minimum angle formed by joining opposite mid sides of quad element

The explanation is: Skew is a quality check parameter for quadrilateral elements. The ideal value of skew should be 0°. The value of skew is acceptable till 45°.