Question

What is the actual equation of stiffness matrix?

(a) K=\(\begin{bmatrix}1 & -1 \\   -1  &  1 \end{bmatrix}\)

(b) K=\(\frac{AE}{l}\begin{bmatrix}1 \\   -1   \end{bmatrix}\)

(c) K=\(\frac{AE}{l}\)

(d) K=\(\frac{AE}{l}\begin{bmatrix}1 & -1 \\   -1  &  1 \end{bmatrix}\)

I got this question by my school principal while I was bunking the class.

This key question is from One Dimensional Problems topic in portion One Dimensional Problems of Finite Element Method

Answer 1

Right option is (d) K=\(\frac{AE}{l}\begin{bmatrix}1 & -1 \\   -1  &  1 \end{bmatrix}\)

Easiest explanation: Stiffness matrix represents the system of linear equations that must be solved in order to ascertain an approximate solution to the differential equation. The stiffness matrix is an inherent property of the structure. A stiffness matrix is a positive definite.