HI, I attach a file that contains a brief test report on a test to
destruction of a typical home made 5/8 inch diameter carbon fibre and epoxy
wing joiner. I was interested to see how far I could push this common sized
joiner used on so may 3 meter gliders. It is a one only test so may not be
fully representative.
If you use the good old Engineers bending equations you get a max stress
around 100 thousand PSI.
Allan J Knox
5/8 Carbon joiner Tests. =09
Fabrication; =09
Made from 200 x 800mm of 450 gram/Sq Meter Carbon uni.
=09
Wet out with ADR Epoxy Resin from Adhesive Technology (Ph 64 p 838 =
6961 Attn Colin Palmer Chemist).Fold back and forward then double =
length wise and pull through the split mould using high force ( boat =
Winch!) . Excess epoxy is squeezed out.
Cook off at 35 Deg C for 3 hours. And condition at room temp for 2 =
weeks.
"Open mould, remove and trim ends."
Test Method;
Apply load symetrically about the mid point at 2 point 4 inches apart. =
Support the ends 14 inches apart. All load points to be pivoting blocks =
with radiused faces. Machine to apply load at steady rate of strain.
Test Results;
Refer the spread sheet.
Failure was by compression .=20
Conclusions;
The test specimen achieved a peak stress of 101 KPSI at a Bend Mom of =
2500 in LBs at initial failure. This was just inboard of the inner =
supports and was due to the local stress concentration at the edge of =
the load application face.
This means the joiner could have carried more load and that 100 KPSI is =
probably a safe Design Maximum.
This is compared with a typical 116 inch F3B soarer with a typical =
multi taper planform on a 200 pound towline.
It produces a Bending Moment of around 2500 in LB which is a good =
match for this joiner.
Data Acquisition Demo Tensile Test on Satec
Time: 103.16333 Sec
Station Name: install.cfg =09
Test File Name: russell_anz.tst =09
Time Axial Displacement Axial Force Axial Strain Bend Mom Bend
Mom =
Stress Stress=09
Hr mm kN mm Newton M in LBs
Kpa KPSI=09
3.19E-04 0.11972964 1.68E-02 -1.34E-04 1.06E+00
9.35E+00 2.69E+03 =
3.90E-01=09
5.97E-04 0.24801038 0.10071091 -4.02E-04 6.34E+00
5.61E+01 1.61E+04 =
2.34E+00=09
8.75E-04 0.45753559 0.18463682 -1.34E-04 1.16E+01
1.03E+02 2.96E+04 =
4.29E+00=09
1.15E-03 0.64568073 0.20142199 -5.37E-04 1.27E+01
1.12E+02 3.23E+04 =
4.68E+00=09
1.43E-03 0.78678954 0.31891826 -9.39E-04 2.01E+01
1.78E+02 5.11E+04 =
7.41E+00=09
1.71E-03 0.9407264 0.35248861 -5.37E-04 2.22E+01
1.96E+02 5.64E+04 =
8.19E+00=09
1.99E-03 1.1117674 0.46998489 -5.37E-04 2.96E+01
2.62E+02 7.53E+04 =
1.09E+01=09
2.26E-03 1.2999125 0.52034044 8.05E-04 3.28E+01
2.90E+02 8.33E+04 =
1.21E+01=09
2.54E-03 1.4367453 0.57069594 -1.74E-03 3.60E+01
3.18E+02 9.14E+04 =
1.33E+01=09
2.82E-03 1.6163384 0.58748114 5.37E-04 3.70E+01
3.27E+02 9.41E+04 =
1.36E+01=09
3.10E-03 1.8173115 0.68819219 2.68E-04 4.34E+01
3.83E+02 1.10E+05 =
1.60E+01=09
3.37E-03 1.9541444 0.7889033 -4.02E-04 4.97E+01
4.40E+02 1.26E+05 =
1.83E+01
3.65E-03 2.1209092 0.82247365 5.37E-04 5.18E+01
4.58E+02 1.32E+05 =
1.91E+01
3.93E-03 2.3047783 0.90639955 -9.39E-04 5.71E+01
5.05E+02 1.45E+05 =
2.11E+01
4.21E-03 2.4715433 0.9567551 1.34E-04 6.03E+01
5.33E+02 1.53E+05 =
2.22E+01
4.49E-03 2.6169281 1.0574661 1.34E-04 6.66E+01
5.89E+02 1.69E+05 =
2.46E+01
4.76E-03 2.7922451 1.1413921 -1.61E-03 7.19E+01
6.36E+02 1.83E+05 =
2.65E+01
5.04E-03 2.9846663 1.1749624 4.02E-04 7.40E+01
6.55E+02 1.88E+05 =
2.73E+01
5.32E-03 3.1471553 1.2421032 -5.37E-04 7.83E+01
6.92E+02 1.99E+05 =
2.88E+01
5.60E-03 3.2925401 1.2924587 -1.34E-04 8.14E+01
7.20E+02 2.07E+05 =
3.00E+01
5.87E-03 3.4336488 1.3763846 -8.05E-04 8.67E+01
7.67E+02 2.20E+05 =
3.20E+01
6.15E-03 3.6388981 1.4435253 -1.34E-04 9.09E+01
8.04E+02 2.31E+05 =
3.35E+01
6.43E-03 3.8227673 1.4938809 -4.30E-10 9.41E+01
8.32E+02 2.39E+05 =
3.47E+01
6.71E-03 3.968152 1.594592 2.68E-04 1.00E+02
8.89E+02 2.55E+05 3.70E+01
6.99E-03 4.100709 1.6281623 -2.68E-04 1.03E+02
9.07E+02 2.61E+05 =
3.78E+01
7.26E-03 4.3102341 1.7288734 -6.71E-04 1.09E+02
9.63E+02 2.77E+05 =
4.02E+01
7.54E-03 4.4812751 1.7624438 -4.02E-04 1.11E+02
9.82E+02 2.82E+05 =
4.09E+01
7.82E-03 4.6010036 1.87994 -1.21E-03 1.18E+02 1.05E+03
3.01E+05 =
4.37E+01
8.10E-03 4.7934246 1.8967252 6.71E-04 1.19E+02
1.06E+03 3.04E+05 =
4.41E+01
8.37E-03 4.9901218 1.9974363 -1.34E-04 1.26E+02
1.11E+03 3.20E+05 =
4.64E+01
8.65E-03 5.1226788 2.0645771 4.02E-04 1.30E+02
1.15E+03 3.31E+05 =
4.80E+01
8.93E-03 5.2680635 2.1317177 -4.30E-10 1.34E+02
1.19E+03 3.41E+05 =
4.95E+01
9.21E-03 5.4690366 2.1988585 2.68E-04 1.39E+02
1.23E+03 3.52E+05 =
5.11E+01
9.49E-03 5.661458 2.2324288 6.71E-04 1.41E+02
1.24E+03 3.57E+05 =
5.18E+01
9.76E-03 5.7811866 2.349925 -4.30E-10 1.48E+02
1.31E+03 3.76E+05 =
5.46E+01
1.00E-02 5.9479518 2.3834953 4.02E-04 1.50E+02
1.33E+03 3.82E+05 =
5.54E+01
1.03E-02 6.1489248 2.433851 -5.37E-04 1.53E+02
1.36E+03 3.90E+05 =
5.65E+01
1.06E-02 6.3028617 2.5009916 -8.05E-04 1.58E+02
1.39E+03 4.00E+05 =
5.81E+01
1.09E-02 6.4653506 2.5849175 -1.34E-04 1.63E+02
1.44E+03 4.14E+05 =
6.00E+01
1.12E-02 6.5936313 2.6352732 -2.68E-04 1.66E+02
1.47E+03 4.22E+05 =
6.12E+01
1.14E-02 6.8031564 2.6856287 -4.30E-10 1.69E+02
1.50E+03 4.30E+05 =
6.24E+01
1.17E-02 6.9314375 2.7695546 -4.02E-04 1.74E+02
1.54E+03 4.43E+05 =
6.43E+01
1.20E-02 7.1281343 2.8031249 1.07E-03 1.77E+02
1.56E+03 4.49E+05 =
6.51E+01
1.23E-02 7.273519 2.903836 1.21E-03 1.83E+02
1.62E+03 4.65E+05 6.74E+01
1.25E-02 7.4915967 2.9541914 2.68E-04 1.86E+02
1.65E+03 4.73E+05 =
6.86E+01
1.28E-02 7.6412573 3.0381174 -5.37E-04 1.91E+02
1.69E+03 4.86E+05 =
7.06E+01
1.31E-02 7.7866421 3.1220434 9.39E-04 1.97E+02
1.74E+03 5.00E+05 =
7.25E+01
1.34E-02 7.9790635 3.1556137 -8.05E-04 1.99E+02
1.76E+03 5.05E+05 =
7.33E+01
1.37E-02 8.1586561 3.2563248 -6.71E-04 2.05E+02
1.81E+03 5.21E+05 =
7.56E+01
1.39E-02 8.2869368 3.3402507 6.71E-04 2.10E+02
1.86E+03 5.35E+05 =
7.76E+01
1.42E-02 8.4323215 3.373821 -1.48E-03 2.13E+02
1.88E+03 5.40E+05 =
7.84E+01
1.45E-02 8.6375713 3.4409618 1.34E-04 2.17E+02
1.92E+03 5.51E+05 =
7.99E+01
1.48E-02 8.8128881 3.4913173 1.34E-04 2.20E+02
1.95E+03 5.59E+05 =
8.11E+01
1.50E-02 8.9582729 3.5584581 2.68E-04 2.24E+02
1.98E+03 5.70E+05 =
8.26E+01
1.53E-02 9.1122103 3.6423841 -9.39E-04 2.29E+02
2.03E+03 5.83E+05 =
8.46E+01
1.56E-02 9.3131828 3.6927395 -2.68E-04 2.33E+02
2.06E+03 5.91E+05 =
8.58E+01
1.59E-02 9.4842243 3.7598803 1.34E-04 2.37E+02
2.10E+03 6.02E+05 =
8.73E+01
1.62E-02 9.6338854 3.843806 1.34E-04 2.42E+02
2.14E+03 6.16E+05 =
8.93E+01
1.64E-02 9.7707176 3.8773766 -2.68E-04 2.44E+02
2.16E+03 6.21E+05 =
9.01E+01
1.67E-02 9.9887953 3.9109468 -1.34E-04 2.46E+02
2.18E+03 6.26E+05 =
9.08E+01
1.70E-02 10.147008 3.9948728 1.21E-03 2.52E+02
2.23E+03 6.40E+05 =
9.28E+01
1.73E-02 10.283841 4.0620136 6.71E-04 2.56E+02
2.26E+03 6.50E+05 =
9.43E+01
1.75E-02 10.442054 4.1291542 -4.30E-10 2.60E+02
2.30E+03 6.61E+05 =
9.59E+01
1.78E-02 10.651579 4.1962948 -4.30E-10 2.64E+02
2.34E+03 6.72E+05 =
9.75E+01
1.81E-02 10.80124 4.2466502 -8.05E-04 2.68E+02
2.37E+03 6.80E+05 =
9.86E+01
1.84E-02 10.946625 4.3137913 -4.02E-04 2.72E+02
2.40E+03 6.91E+05 =
1.00E+02
1.87E-02 11.134769 4.3809319 4.02E-04 2.76E+02
2.44E+03 7.02E+05 =
1.02E+02
1.89E-02 11.305811 4.4312873 -4.02E-04 2.79E+02
2.47E+03 7.10E+05 =
1.03E+02
1.92E-02 11.455472 4.4816427 2.68E-04 2.82E+02
2.50E+03 7.18E+05 =
1.04E+02
1.95E-02 11.605132 4.4480724 2.68E-04 2.80E+02
2.48E+03 7.12E+05 =
1.03E+02
1.98E-02 11.810382 4.3305764 9.39E-04 2.73E+02
2.41E+03 6.93E+05 =
1.01E+02
2.00E-02 11.985699 4.2970061 4.02E-04 2.71E+02
2.39E+03 6.88E+05 =
9.98E+01
2.03E-02 12.118256 4.2970061 -2.68E-04 2.71E+02
2.39E+03 6.88E+05 =
9.98E+01
2.06E-02 12.276468 4.280221 -1.07E-03 2.70E+02
2.39E+03 6.85E+05 =
9.94E+01
2.09E-02 12.481717 4.3305764 -1.07E-03 2.73E+02
2.41E+03 6.93E+05 =
1.01E+02
2.12E-02 12.652759 4.3641467 -2.68E-04 2.75E+02
2.43E+03 6.99E+05 =
1.01E+02
2.14E-02 12.781039 4.3641467 2.68E-04 2.75E+02
2.43E+03 6.99E+05 =
1.01E+02
2.17E-02 12.943528 4.3809319 -2.68E-04 2.76E+02
2.44E+03 7.02E+05 =
1.02E+02
2.20E-02 13.135949 4.1459394 2.68E-04 2.61E+02
2.31E+03 6.64E+05 =
9.63E+01
2.23E-02 13.319818 4.0620136 -4.30E-10 2.56E+02
2.26E+03 6.50E+05 =
9.43E+01
2.25E-02 13.435271 4.1123691 6.71E-04 2.59E+02
2.29E+03 6.59E+05 =
9.55E+01
2.28E-02 13.636244 4.1291542 -4.02E-04 2.60E+02
2.30E+03 6.61E+05 =
9.59E+01
2.31E-02 13.815837 4.1459394 -5.37E-04 2.61E+02
2.31E+03 6.64E+05 =
9.63E+01
2.34E-02 13.974051 4.1291542 1.34E-04 2.60E+02
2.30E+03 6.61E+05 =
9.59E+01
2.37E-02 14.093779 4.1123691 4.02E-04 2.59E+02
2.29E+03 6.59E+05 =
9.55E+01
2.39E-02 14.311856 4.1123691 -5.37E-04 2.59E+02
2.29E+03 6.59E+05 =
9.55E+01
2.42E-02 14.487173 4.1459394 -2.68E-04 2.61E+02
2.31E+03 6.64E+05 =
9.63E+01
2.45E-02 14.61973 4.1627245 -5.37E-04 2.62E+02
2.32E+03 6.67E+05 =
9.67E+01
2.48E-02 14.786495 4.1291542 -1.21E-03 2.60E+02
2.30E+03 6.61E+05 =
9.59E+01
2.50E-02 14.97464 4.1459394 4.02E-04 2.61E+02
2.31E+03 6.64E+05 =
9.63E+01
2.53E-02 15.149957 4.1459394 1.34E-04 2.61E+02
2.31E+03 6.64E+05 =
9.63E+01
2.56E-02 15.282514 4.1291542 -4.02E-04 2.60E+02
2.30E+03 6.61E+05 =
9.59E+01
2.59E-02 15.440727 4.1123691 -4.02E-04 2.59E+02
2.29E+03 6.59E+05 =
9.55E+01
2.62E-02 15.6417 4.0787988 -2.68E-04 2.57E+02 2.27E+03
6.53E+05 =
9.47E+01
2.64E-02 15.804189 4.0284429 -4.02E-04 2.54E+02
2.24E+03 6.45E+05 =
9.36E+01
2.67E-02 15.962401 4.0116577 -5.37E-04 2.53E+02
2.24E+03 6.42E+05 =
9.32E+01
2.70E-02 16.150547 3.9948728 -4.02E-04 2.52E+02
2.23E+03 6.40E+05 =
9.28E+01
2.73E-02 16.30876 3.9948728 -8.05E-04 2.52E+02
2.23E+03 6.40E+05 =
9.28E+01
2.75E-02 16.484077 3.9109468 -5.37E-04 2.46E+02
2.18E+03 6.26E+05 =
9.08E+01
2.78E-02 16.608082 3.9613023 5.37E-04 2.50E+02
2.21E+03 6.34E+05 =
9.20E+01
2.81E-02 16.79195 3.927732 6.71E-04 2.47E+02
2.19E+03 6.29E+05 9.12E+01
2.84E-02 16.992924 3.9109468 8.05E-04 2.46E+02
2.18E+03 6.26E+05 =
9.08E+01
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