OREGON STATE UNIVERSITY
ME 453 – STRUCTURE AND MECHANICS LABORATORY
Lab Experiment Guidelines – Project #2 – Winter 2012
The following illustration (Figure 1) shows the beam for the fiber reinforced composite experiment.
Please use the labeling scheme for the gauges and the coordinate systems as shown.
F
z
Side View
x
y
Top View
2
a
b
x
c
1
Figure 1. Analysis/experiment coordinate system (x,y,z), material coordinate system (1,2,3), and
rosette strain gauge orientation and labeling (a,b,c).
INTRODUCTION
The purpose of the LabVIEW programs for this experiment are to collect rosette gauge and marker
displacement data in order to validate composite beam bending calculations.
The process of validation is somewhat different than the isotropic beam experiment. For that lab you
calculated stresses using simple beam equations, converted the stresses to strain using Hooke’s
Law, and compared the measured and calculated strains.
For the composite beams you will calculate strain and curvature from lamina properties, lay-up
geometry, and beam loading. The calculated and measured strains will be directly compared. Stress
is a follow-on calculation after strains are determined. Displacement is also a follow-on calculation
after curvatures are determined.
LABVIEW PROGRAMS
You will use LabVIEW and our data acquisition hardware to accomplish two tasks:
1
1. Collect and process strain gauge rosette information, similar to Lab 1.
2. Collect and process images of the beam in bending to determine marker displacements.
These two functions can be instantiated in separate programs or combined into a single LabVIEW vi.
You will ultimately conduct a beam bending experiment similar to Lab 1, with the beam loaded by
weights stacked at the end and strain/displacement information collected for repeat experiments.
Recycle your strain gauge program from Lab 1. Note that you will have to adjust the rosette
conversion matrix to reflect the new coordinate system.
We will provide a starter program for image acquisition since this requires some rather specialized
LabVIEW vi’s.
COMPOSITE BEAM ANALYSIS
You also have available an Excel spreadsheet titled “Composites Calculator Example.” You will
modify this spreadsheet to reflect the actual beams used in the lab, and extend the calculations.
2