Carbon Fiber/Epoxy Composite B Basis Calculation And Analysis Of Its Influencing Factors

Since the 21st century,resin matrix composites have been changing from military field to civil field,and the proportion of composite materials in structural parts is increasing.In the structural design of composite materials,the design allowable value of composite materials is one of the most critical parameters.The statistic of the B Basis is usually used as the allowable value.The B Basis is the lower limit of 90% confidence defined at the 95% confidence level.Exploring a method for calculating the B Basis of composite material with high accuracy and low test cost is a guarantee for the safety,reliability and wide application of composite materials.At present,the domestic B Basis research is still in the stage of tracking foreign countries,and there are many problems such as insufficient understanding of the essence of calculation,and the nature of the factors that influence the calculation results are not clear.Therefore,this paper takes carbon fiber/epoxy resin matrix composites as the research object to study the influencing factors and essence of the calculation process of the B Basis.Firstly,in order to obtain sufficient and reasonable sample data,a batch of carbon fiber-reinforced epoxy resin-based composite materials were prepared by hand layup molding process,hot press molding process,prepreg-autoclave molding process,and winding molding process.Strictly according to relevant standards such as ASTM and SACMA,carried out mechanical properties experiments such as 0° stretching,0°compression,90° stretching,three-point bending,and interlaminar shear at different temperatures,and the failure modes of various experiments were consistent.The analysis is performed to ensure the scientific nature of the data source for calculating the B Basis.Secondly,on the basis of the research of many experts,this article analyzes in detail the calculation principles,calculation process,applicable conditions,engineering experience judgment factors,etc.of the single-point method and the pooling method,and provides some statistical and calculation principles.Through deep research,the new methods and new ideas for some calculation steps were proposed.Using software to realize the calculation of the single-point method,and analyze the reliability of the calculation results,which has certain engineering significance.Finally,the nature of the influence of various calculation methods and various factors on the calculation results of the B Basis is studied.Using software to analyze and calculate a large number of examples,and determine the scientificity of the CMH-17 G calculation process compared with other methods;combined with SEM microanalysis,resin curing theory and engineering examples to determine the molding process,temperature,aging time,and experimental equipment The essential reason why factors such as standards and standards affect the calculation results of the B Basis: change the calculation results of the B Basis by changing the macroscopic mechanical property dispersion coefficient.