Composites epoxy

The results presented below were obtained using a 2 mm thick carbon fiber reinforced epoxy composite laminate with 16 layers. The laminate was quasi isotropic with fiber orientations 0°, 90° and 45°. The laminate had an average porosity content of approximately 1.7%. The object was divided in a training area and an evaluation area. The model parameters were determined by data solely from the training area. Both ultrasound tranducers used in the experiment had a center frequency of 21 MHz and a 6 dB bandwidth of 70%. 

Katsumata,. M. and Endo, M, J.,Epoxy composites using vapor-grown carbon fiber... 

Crivello, J.V., Electron beam curable epoxy compositions, US Patent 5,260,349, 1993. Janke, C.J., Dorsey, G.F., Havens, S.J. and Lopata, V.J., A toughened epoxy resin system and a method thereof, US Patent 5,726,216, 1998. 

Crivello, J.V., Electron beam curable epoxy compositions. US Patent 5,260,349, 1993. 

Example 3.7 A thin unidirectional Kevlar fibre/epoxy composite has the properties listed below. If the fibres are aligned at 6 to the x-axis, show how... 

Example 3.13 A single ply of carbon fibre/epoxy composite has the following properties ... 

Fig. 3.24 Variation of elastic properties for a single ply of carbon/epoxy composite...

A unidirectional glass fibte/epoxy composite has a fibre volume fraction of 60%. Given the data below, calculate the density, modulus and thermal conductivity of the composite in the fibre direction. 

In a unidirectional Kevlar/epoxy composite the modular ratio is 20 and the epoxy occupies 60% of the volume. Calculate the modulus of the composite and the stresses in the fibres and the matrix when a stress of 50 MN/m is applied to the composite. The modulus of the epoxy is 6 GN(m. ... 

In a unidirectional carbon fibre/epoxy composite, the modular ratio is 40 and the fibres take up 50% of the cross-section. What percentage of the applied force is taken by the fibres ... 

A unidirectional carbon hbre/epoxy composite has the following lay-up... 

A single ply glass/epoxy composite has the properties Usted below. If the fibres are aligned at 30° to the x-direction, determine the value of in-plane stresses, a, which would cause failure according to (a) the Maximum Stress criterion (b) the Maximum Strain criterion and (c) the Tsai-Hill criterion. 

A carbon/epoxy composite with the stacking arrangement [0/ - 30/30]j has the properties listed below. Determine the value of in-plane stress which would cause failure according to the (a) Maximum Strain (b) Maximum Stress and (c) Tsai-Hill criteria. 

The preceding restrictions on engineering constants for orthotropic materials are used to examine experimental data to see if they are physically consistent within the framework of the mathematical elasticity model. For boron-epoxy composite materials, Dickerson and DiMartino [2-3] measured Poisson s ratios as high as 1.97 for the negative of the strain in the 2-direction over the strain in the 1-direction due to loading in the 1-direction (v 2)- The reported values of the Young s moduli for the two directions are E = 11.86 x 10 psi (81.77 GPa) and E2 = 1.33x10 psi (9.17 GPa). Thus,... 

To gain a visual appreciation for how the moduli vary, values typical of a glass-epoxy composite material are plotted from Equation... 

Several experiments will now be described from which the foregoing basic stiffness and strength information can be obtained. For many, but not all, composite materials, the stress-strain behavior is linear from zero load to the ultimate or fracture load. Such linear behavior is typical for glass-epoxy composite materials and is quite reasonable for boron-epoxy and graphite-epoxy composite materials except for the shear behavior that is very nonlinear to fracture. 

As with the maximum stress failure criterion, the maximum strain failure criterion can be plotted against available experimental results for uniaxial loading of an off-axis composite material. The discrepancies between experimental results and the prediction in Figure 2-38 are similar to, but even more pronounced than, those for the maximum stress failure criterion in Figure 2-37. Thus, the appropriate failure criterion for this E-glass-epoxy composite material still has not been found. 

The Tsai-Hill failure criterion appears to be much more applicable to failure prediction for this E-glass-epoxy composite material than either the maximum stress criterion or the maximum strain failure criterion. Other less obvious advantages of the Tsai-Hill failure criterion are ... 

---