Estimate of compressive strength of an unidirectional composite lamina using cross-ply and angle-ply laminates

In this work has been estimated the compressive strength of a unidirectional lamina of a carbon/epoxy composite material, using the cross-ply and angle-ply laminates. Over the years various methods have been developed to deduce compressive properties of composite materials reinforced with long fibres. Each of these methods is characterized by a specific way of applying load to the specimen. The method chosen to perform the compression tests is the Wyoming Combined Loading Compression (CLC) Test Method, described in ASTM D 6641 / D 6641M-09. This method presents many advantages, especially: the load application on the specimen (end load combined with shear load), the reproducibility of measurements and the experimental equipment quite simplified. Six different laminates were tested in compressive tests. They were realized by the same unidirectional prepreg, but with different stacking sequences: two cross-ply [0/90]ns, two angle-ply [0/90/±45]ns and two unidirectional laminates [0]ns and [90]ns. The estimate of the compressive strength of the unidirectional laminates at 0°, was done by an indirect analytical method, developed from the classical lamination theory, and which uses a multiplicative parameter known as Back-out Factor (BF). The BF is determined by using the experimental values obtained from compression tests. Finally, extrapolated data were compared with prepreg manufacturer datashee

Estimate of compressive strength of an unidirectional composite lamina using cross-ply and angle-ply laminates

In this work has been estimated the compressive strength of a unidirectional lamina of a carbon/epoxy composite material, using the cross-ply and angle-ply laminates. Over the years various methods have been developed to deduce compressive properties of composite materials reinforced with long fibres. Each of these methods is characterized by a specific way of applying load to the specimen.The method chosen to perform the compression tests is the Wyoming Combined Loading Compression (CLC) Test Method, described in ASTM D 6641 / D 6641M-09. This method presents many advantages, especially: the load application on the specimen (end load combined with shear load), the reproducibility of measurementsand the experimental equipment quite simplified. Six different laminates were tested in compressive tests. They were realized by the same unidirectional prepreg, but with different stacking sequences: two cross-ply [0/90]ns, two angle-ply [0/90/±45]ns and two unidirectional laminates [0]ns and [90]ns.The estimate of the compressive strength of the unidirectional laminates at 0°, was done by an indirect analytical method, developed from the classical lamination theory, and which uses a multiplicative parameterknown as Back-out Factor (BF). The BF is determined by using the experimental values obtained from compression tests

Experimental determination of compressive strength of an unidirectional composite lamina: indirect estimate by Using Back-out Factor (BF)

In this paper, the determination of compressive strength of an unidirectional lamina (carbon/epoxy composite), using the Back-Out Factor correction of experimental data, is presented. Since early \u201970s, many methods were developed to deduce a compressive characterization of a composite material, each of which has been based on a different way of applying load to specimens. After a detailed examination of these methods, the ASTM D 6641/D 6641M-09 Test Method has been chosen due to its advantages, i.e. load application to the sample (end load combined with shear load), measurement reproducibility and experimental equipment quite simplified. The experimental equipment (according to ASTM D 6641) used for compressive tests is the Wyoming Combined Loading Compression (CLC) Test Fixture. Four different laminates were tested in compressive tests. They were realized by the same unidirectional prepreg, but with different stacking sequences: two cross-ply [0/90]ns and two unidirectional laminates, [0]ns and [90]ns. The last two laminates were used to evaluate the linear elastic properties of unidirectional lamina. The Back-Out Factors, that multiply the laminate measured compressive strength, were determined using the elastic properties previously measured. This indirect analytic method, developed from the classical lamination theory, was used to find out the unidirectional 0\ub0 lamina compressive strength. At last, extrapolated data were compared with pre-preg manufacturer datasheet