MECH 5350 Introduction to FEM: Hw2

HW2 (Due 09/21 in class)

1. For the following matrix and vector

1 2 6

2 2 3

1 3 0

A=

,

0

3

2

b=

Find: (a) Determinant det A , (b) 1A

(c) Solution to Ax b (d) Values of the quadratic form

x AxT

2. A spring system is shown below

Given: 1 2 3 1 480 / , 100 / , 160 / , 200 , 100 .k N mm k N mm k N mm F N F N Node 1 and 2 are fixed.

Find: (1) Global stiffness matrix; (2) displacements at node 3 and 4; (3) Reaction force at node 1 and 2

(4) Force in spring 1 and 2.

3. Textbook problem 2.2-2, 2.2-3 (see attached sheet on e-learning)