Composite Flexure Test Information
for Vanessa Kohlhepp, Chemistry Dept., MS&T

Summary

• Composite material consisted partly of Kevlar fibers, epoxy resin, and magnesium oxide.
• Followed ASTM D2344-84 using a span length-to-depth ratio of 5 and a speed of 0.05 in/min.
• Calculated modulus of elasticity in multiple ways:
  1. Let the Instron software calculate it automatically.
  2. Used equation in ASTM D790-83 to calculate it from the slope of load-deflection curve, which the Instron software determined automatically.
  3. Used equation from simple beam theory to calculate it from the (maximum) load and the accompanying deflection, which the Instron user selected with the mouse after the test.
• ASTM D2344 title: Apparent Interlaminar Shear Strength of Parallel Fiber Composites by Short-Beam Method
• ASTM D790 title: Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials

Test Setup

ASTM D790 Equations

ASTM D2333 Equations

Beam Theory Equations

Specimen Images

Computer Printouts

Click to enlarge.

Spreadsheet Calculations