With the continuous development of technology, carbon fiber composite materials are widely used in aerospace materials, auto parts, medical equipment and other fields. Compared with the original carbon fiber composite material, the composite material with the same layer of carbon fiber foam sandwich structure has higher strength and lighter weight. It has great advantages in the application of covering parts and load-bearing parts, and its application prospect is very broad. .
The carbon fiber sandwich panel is a sandwich structure composed of a panel and a core material. The panel has high strength and high rigidity, but the thickness is thin; the strength and rigidity of the sandwich are low, but the thickness is relatively thick. For the sandwich structure, it is necessary to make full use of the bearing capacity of the panel to improve the structural efficiency. In fact, when the sandwich panel is used as the structural element, it also makes full use of its high bending stiffness-to-mass ratio.
However, the sandwich structure's ability to transmit concentrated loads is weak, and localized pull-out and squeeze failure will occur under the effect of concentrated loads, so that the panel and the inner core are peeled off. In order to improve the sandwich structure's ability to transmit concentrated loads, the edge design of the sandwich panel and special connection forms should be considered in the design of the sandwich structure connection. Therefore, we propose the following principles for the connection design of the sandwich structure.
(1) Improve the extrusion strength of the panel in the connection area. In the connection part of the connection area, increase the layout reinforcement according to the size of the load to improve the hole edge compression strength. For the reinforced layup of laminate panel, it should be laid in the direction of ±45° to the load direction.
(2) Reduce the squeeze load of the panel hole. Reinforcement sheet method can be used at the connection part to spread most of the load to the panel through the glued surface to reduce the squeeze stress of the panel hole.
(3) Avoid connecting only with the upper or lower panel. When mechanically connecting, avoid connecting with only one panel to prevent the peeling and damage of the adhesive layer between the panel cores caused by the pulling force of the connecting nail. For this reason, the connection of the sandwich structure should try to fix the connecting nail and the core, and bear the tensile force of the nail through the shear of the core.
It can be seen that with the thickening of the carbon fiber composite panel layer or the foam core layer, the slope of the curve decreases, the better the rigidity of the foam core structure carbon fiber composite material, and the critical point is also getting more and more backward, carbon fiber composite The thickness of the material panel layer plays a decisive role in the critical point. JSBS Carbon Fiber Technology Co., Ltd. is a manufacturer of carbon fiber composite products. Since its establishment, it has been devoted to the development of carbon fiber composite materials, structural development, technical development and other services. The company's products are made of Toray's raw materials and the quality is guaranteed.