Hi Everybody
Apart from being very complex, composite calculations have to be tested empirically. As uni carbon clothes are anyway at a minimum of 100g/m2 per layer the discretisation of layers doesnt offer many possible combinations.
In order to validate a wingskin structure that resists the sheer calculations of the EAA spreadsheets I post three pics of HKW aero that shows sample destructive testing.
I would appreciate if you could comment on the different testing fundamentals.
1- Are the three tests validating the same results? The first one looks like torsion the others two tests look for compression on the lower wingskin? Needs the test to be conducted upside down with the same parameters?
2-How wide should the sample sections be? At lease as wide as long
3- Having ribs at both ends, doesnt that distort the results? I wont use ribs at all.
4- In the first test should the bar end be screwed against the spar plate and the mid attachment against the rib or a tube bonded into the leading edge?
5- We dont want to test for buckling. If we use a 10mm high quality sandwich foam or honeycomb can we spare buckling tests?
6- A buckling test would be to curve a D cell down on every end while fixing the Dcell at the spar in the center? Again which would be the limit bucling deformation?
7- Should I destroy the Dcells in front of the spar and the section behind the spar in the same way?
8- Test picture 2 shows the deflection of the Dcell. How would we establish the max allowed deflection.
9- ..............
Please share your thoughts on this important topic.
Apart from being very complex, composite calculations have to be tested empirically. As uni carbon clothes are anyway at a minimum of 100g/m2 per layer the discretisation of layers doesnt offer many possible combinations.
In order to validate a wingskin structure that resists the sheer calculations of the EAA spreadsheets I post three pics of HKW aero that shows sample destructive testing.
I would appreciate if you could comment on the different testing fundamentals.
1- Are the three tests validating the same results? The first one looks like torsion the others two tests look for compression on the lower wingskin? Needs the test to be conducted upside down with the same parameters?
2-How wide should the sample sections be? At lease as wide as long
3- Having ribs at both ends, doesnt that distort the results? I wont use ribs at all.
4- In the first test should the bar end be screwed against the spar plate and the mid attachment against the rib or a tube bonded into the leading edge?
5- We dont want to test for buckling. If we use a 10mm high quality sandwich foam or honeycomb can we spare buckling tests?
6- A buckling test would be to curve a D cell down on every end while fixing the Dcell at the spar in the center? Again which would be the limit bucling deformation?
7- Should I destroy the Dcells in front of the spar and the section behind the spar in the same way?
8- Test picture 2 shows the deflection of the Dcell. How would we establish the max allowed deflection.
9- ..............
Please share your thoughts on this important topic.
