Composite Tensile Tests

General Composites Discussions Showcase
#1

So a followup to my previous post. The coupons I made previously wouldn’t break in tension, but rather the tabs sheared off so I had to make new ones. I tested them and here are the videos!

I’m testing the difference in strength between uniaxial and biaxial material. They’re both made of Toray t700 fibers woven together by Textile Products Inc. One is unidirectional and the other is 2x2 twill. Both were infused.

http://www.youtube.com/watch?v=u_XDUWgzs_Y
http://www.youtube.com/watch?v=R2s1KpbBRJs

Some preliminary data. The uniaxial is slightly stiffer and slighty stronger. The breaking strength for both were around ~3500 lbs and the cross section is about .503 inches by .055 inches.

I have reams of data and once I finish crunching the numbers I’ll post my results for all to see!

#2

odd. Would have figured if they have the same cross area, the uni should be 50% higher than the 0/90.

#3

I should explain further. The goal of this project was to make the two samples identical in every factor except weave. Here’s the lay order

Bidirectional weave - Two layers
Both stacked in same direction

Unidirectional weave- Four layers
0
90
0
90
Alternating

So both samples have roughly the same amount of fiber running in perpendicular directions.
I probably should have said weave in the first place :p. My apologies

#4

Full results for anyone interested

Bidirectional
Failure Strength kpsi
107
1112
116
122
124
125
129
131

Average Modulus
7.51 Mpsi

Average Ultimate Strength
121 kpsi

Weibull Modulus
15.54

Unidirectional
Failure Strength kpsi
127
132
133
136
138
138
138
139

Average Modulus
8.01 mpsi

Average Ultimate Strength
135 kpsi

Weibull Modulus
31.84