L04: Space Truss Static Analysis✔

Owned by Gokhan Alkan (Unlicensed)
Last updated: Jul 05, 2019

Three element space truss supports 50 lb load. The bars are attached to the ceiling. The truss elements are steel (E = 30x10^6 psi) and the cross-sectional area of each element is 1 in^2. Determine the axial force in each bar.



The model consists of 4 joints and 3 truss elements. The rotational degrees of freedom are deleted from the 3D model. The joints 1, 2 and 3 are pin supports.

The material property data is given as:

Modulus of Elasticity = 30,000,000 lb/in^2


The sectional property data for the truss bar is:

Area of each truss bar = 1 in^2


The load of 50 lb is applied in the vertical Global Z-direction. The applied load is:

Load P @ Joint 4 in Z = -50 lb


Linear static analysis with one (1) load case is performed.

All truss elements are in tension.



Tested Features


App

Object Link: https://openbrim.org/objidlhmn9ovakfckbgfyo137xi.project

Library

Object Link: https://openbrim.org/objidfcp3gro45cp3reoyqjpzxg.libobj


Sources

  • Beer, F.P., and Johnston, Jr., E.R., "Vector Mechanics for Engineers, Statics and Dynamics," McGraw-Hill Book Co., Inc. New York, 1962, p. 47.
  • LARSA 4D


Result Comparison


Independent

(Beer)

LarsaOpenBrIM

Percent Difference

(Larsa vs Independent)

Percent Difference

(OpenBrIM vs Independent)

Truss force F1 (lb)0.01040.01040.01040%0%
Truss force F2 (lb)0.03120.03120.03120%0%
Truss force F3 (lb)0.02290.02290.02290%0%