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E-02 (Curved Brick Beam)

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Objective

To verify the incompatible brick element in a curved structure

 

Problem Description

A curved beam as shown below [Ref 1] is fixed at the bottom and loaded with two sets of loads at the tip: 1.0 lbf in-plane shear and 1.0 lbf out-of-plane shear.

 

Material properties: E = 1.0e7 psi, ν = 0.25

 

Plate thickness t = 0.1 in

 

Curved beam inner radius = 4.12 in, outer radius = 4.32 in, arc = 90o

 

E-02 (Curved Brick Beam)1

 

Finite Element Model

6 brick elements

Model type: 3D Brick (use incompatible formulations)

 

Results

The tip displacements in the direction of loads given by ENERCALC 3D are compared with that given by [Ref 1] as follows:

Unit: displacement - in

 

Displacement in load direction

ENERCALC 3D

[Ref 1]

6 x 1 mesh

20 x 1 mesh

In-plane shear (in)

0.07682

0.08814

0.08734 (see Note)

Out-of-plane shear (in)

0.4116

0.4797

0.5022

Note:  The displacement given by [Ref 1] is smaller than the theoretical calculation based on the following [Ref 2]:

E-02 (Curved Brick Beam)2 in

E-02 (Curved Brick Beam)3 in4

E-02 (Curved Brick Beam)4 in

 

Comments

The results given by ENERCALC 3D are very good considering the relatively coarse meshes employed.  We would obtain better results if more elements were used along the beam length.

 

Reference

[1]. MacNeal & Harder, “A Proposed Standard Set of Problems to Test Finite Element Accuracy”, Finite Elements in Analysis and Design, 1 (1985) 3-20

[2]. Roark & Yong, “Formulas for Stress and Strain” 5th Ed, pp215, McGraw-Hill Inc., 1975