Study On Three-dimensional Orthogonal Composite Panel Manufacturing And Its Off-axial Angle Sensitivity Of In-plane Compression Performance

Fabric reinforced composite materials are widely used in various engineering fields due to their excellent material properties.Among them,three-dimensional orthogonal woven(3DOW)composite materials are often used as load-bearing members because of their excellent axial mechanical properties and high fiber volume content.Therefore,the axial mechanical properties have been extensively studied.However,due to the complex shape of composite materials,local stresses are usually multiaxial,and composite materials often have different mechanical properties and damage mechanisms in different directions due to their anisotropic structural characteristics.Therefore,studying the effect of off-axial load on the mechanical properties of 3DOW composites has important theoretical value and practical application significance.This paper studies the weaving process of three-dimensional fabrics,completes the design and construction of three-dimensional looms,manufactures 3DOW composite materials,and studies when the load direction and the direction of the main load-bearing yarn are at different off-axial angles,the material The difference between the displayed mechanical response and the damage mechanism.Through the analysis of the three-dimensional woven fabric weaving process,a three-dimensional fabric weaving prototype was designed and built to weave the three-dimensional orthogonal fabric suitable for this research.The 3DOW composite material in-plane compression test was carried out under quasi-static and dynamic loading conditions,and the mechanical response of the material when the loading direction and the weft direction were at different angles were analyzed.In the in-plane compression test,an infrared thermal imaging camera was used to capture the heat generated during the damage process to record the temperature rise of the sample surface,and based on the test results,the damage development behavior of the sample under static conditions was studied.In addition,a mesoscopic finite element model including reinforced tow,resin matrix and interface layer was established.The simulation results further reveal the damage mechanism of composite materials and the effect of binding yarn.The main content and conclusions of this article are as follows:1)Based on the principle of three-dimensional fabric weaving technology,the mechanical structure and control software are designed,and a three-dimensional woven fabric weaving platform is developed.2)Perform quasi-static and dynamic in-plane compression tests on 3DOW composite materials with different off-axial angles through the universal testing machine and SHPB test platform,and analyze the compression properties of the materials.The results show that as the off-axial angle increases,the elastic modulus and compressive strength have a decreasing trend,while the damage strain increases.In addition,the increase of the off-axial angle will gradually transform the material damage from brittle damage to plastic damage.3)Analyzing the temperature rise of the sample surface,it is found that as the off-axial angle increases,the sample gradually changes from a small range of high temperature rise to a large range of low temperature rise.4)The finite element simulation modeling of the dynamic compression test on the mesoscopic scale was carried out,and the in-plane compression process of the normal axial and 45° off-axial composite material under the dynamic compression load was simulated.The results of the simulation are used to verify the conclusions obtained from the experiment,and further study the mechanism of material damage and the effect of binding yarn.5)For the on-axial sample,the weft as the load-bearing yarn produces out-of-plane displacement after being broken due to the compressive load,which causes the binding yarn to fail and a high temperature rise in the binding yarn area.As the off-axial angle increases,the main damage mode in the material changes from yarn damage to interlayer delamination and resin matrix damage,and the temperature rise at the position where the yarn is tied gradually decreases;for the 45° off-axial test In this way,the weft and warp yarns rotate in the compression plane due to the coupling torque caused by the fiber direction and the compression load direction,which eventually leads to fiber splitting and interlayer delamination.The binder yarn helps to improve the in-plane compressive strength and has different enhancement effects in the axial and off-axial specimens.In the axial sample,the binding yarn restricted the out-of-plane movement of the weft yarn and delayed the occurrence of delamination damage.The binding yarn of the 45° sample restricts the in-plane rotation of the yarn and suppresses delamination between layers.