Carbon fiber composite materials have high strength and stiffness in the fiber direction, but very low strength and stiffness in the vertical fiber direction. In practical applications, such materials appear in the form of laminates.
The experimental material is T300 carbon fiber /epoxy resin composite laminate, 10 layers of symmetrical layup, each layer thickness is 0.15mm, and the thickness of the composite laminate is 1.50mm. 90/0]s, and the laying sequence of specimens in the 90° direction is [±45/90/0/90]s. It is a type of laminate mainly used in engineering at present, and can obtain greater in-plane shear stiffness and strength.
Through the test and comparison of the test data, it can be known that: Tensile strength: the average failure strength of the specimens in the 0 and 90° directions are 940.11MPa and 458.63MPa respectively, and the average failure strength in the 0 direction is 2.05 times that in the 90° direction. Elastic modulus: During the tensile test, the average elastic modulus in the 0° and 90° directions are 89.45GPa and 48.35GPa, respectively, and the average elastic modulus in the 0° direction is 1.85 times that in the 90° direction. During the compression test, the average failure strength of the specimens in the 0° and 90° ply directions were 506.77MPa and 419.90MPa, respectively, and the average failure strength in the 0° direction was 1.21 times that in the 90° direction.
It can be seen from the above data that in the tensile test, the mechanical properties of the T300 carbon fiber composite material in the 0° direction are significantly better than those in the 90° direction. This is because the fiber layup direction of the 0° direction specimen is [±45/0/90/0]s, and the fiber layup direction of the 90° direction specimen is [±45/90/0/90]s. The middle two layers of fibers of the 0° direction specimen are along the direction of the force, while the middle two layers of fibers of the 90° direction specimen are perpendicular to the direction of the force. However, the fibers of the specimen in the 0° direction can bear larger loads along the force direction.
Therefore, when using this material, it is necessary to make the material 0° ply direction bear the main tensile pressure as far as possible, so as to achieve the most ideal use effect.
In the compression test, the mechanical properties of the T300 carbon fiber composite material in the 0° direction are better than those in the 90° direction.
However, the difference in the mechanical properties of the two specimens is significantly smaller than that in the tensile test, because in the compression test, the compressive mechanical properties of the specimen mainly depend on the firmness between the layers of the specimen, and the laying direction of the fibers affects Therefore, the mechanical properties of the two specimens are not much different.