Where G is the Shear Modulus of the Composite and other values are as defined previously. We can create the above sample, apply a known Force and measure the subsequent deflection (or vice versa) But unfortunately, there are two unknowns in the above equation (E and G) - The material constants we are trying to calculate. However, if we test the same (or an identical) sample as a simply supported beam with an applied load we can derive a further equation in E and G that will enable us to solve the two simultaneous equations for E and G It is possible to create simple tests that could be used to calculate the Orthotropic material properties of a complex layup (and act as FE benchmarks). This could be very useful as a manufacturing quality check or for use in FEA if individual layup properties are not known. Consider the simple Cantilever below Deriving Orthotropic material properties Solving simultaneous equations gives the following So if the above tests are also performed in the orthogonal direction then the 2D homogeneous Orthotropic material properties can be obtained. These can either be used in FEA or as quality tests for manufacture when compared with FEA.