Study On Properties Of Composites Prepared By Pultrusion-Vacuum Infusion Process

As a key equipment in wind turbines,it is very important to further reduce manufacturing costs of wind turbine blades based on improving performance,which is crucial for domestic blade manufacturers to maintain and develop.In order to achieve this goal,this paper based on the engineering practice of wind turbine blades,try to improve the vacuum infusion molding process(VIMP),which is the most commonly used for the preparation of the beam of wind turbine blades.Firstly,prepared pultrusion plates by pultrusion process,and then prepared the beam samples by VIMP with the pultrusion plates stacked together.The mechanical properties and fatigue properties of the samples were tested.In this paper,glass fiber and carbon fiber,were selected as reinforcing materials to prepare the pultrusion plates respectively.The tensile properties,compressive properties,bending properties and shearing properties of the pultrusion plates were tested and were compared with the same size VIMP composite plates.The results show that the pultrusion plates have a 10 percent higher fiber volume fraction,better tensile properties,compression properties and bending properties;the shearing strength of the glass fiber pultrusion plates is reduced,and the shearing strength of the carbon fiber pultrusion plates is basically flat.In this paper,the pultrusion plates were further used as pre-embedded parts to prepare the pultrusion-vacuum infusion molding process composites by VIMP.And the samples of the 2-layer pultrusion plates were tested for tensile,compression,bending and shearing properties,and compared with the original pultrusion plates.The results show that the basic mechanical properties of the pultrusion-vacuum infusion molding process composites were generally reduced.Compared with the same size VIMP composites,the results showed that when glass fiber was used as the reinforcing fiber,its overall mechanical properties improved obviously.When carbon fiber was used as the reinforcing fiber,the shearing property decreased obviously.The pultrusion-vacuum infusion molding process composites of the 6-layer pultrusion plates were subjected to four-point bending fatigue test,and compared with the same size VIMP samples.The results show that when glass fiber is used as reinforcing fiber,the fatigue performance is improved by 54.61%at low strain level,and the fatigue performance is improved by 6.5 times at high strain level.When carbon fiber is used as reinforcing fiber,the fatigue performance is improved by 70.59%at the low strain level,the fatigue performance is decreased by 56.10%at the high strain level.Finally,the finite element analysis method was used to numerically analyze the ultimate strength and fatigue performance of the samples.The numerical analysis results were compared with the test results,and the error between them is within the acceptable limits.