A rapid method for determining Weibull parameters of carbon fiber strength

This study proposes a new rapid measurement method for determining the Weibull parameters of carbon fiber strength distribution based on tensile testing of carbon fiber bundles. Unlike traditional fiber bundle tests, which require both stress and strain measurements, this method only requires testing the tensile strength of the fiber bundles. The process involves three key steps: First, a formula derived from the Weibull distribution function was used to establish the relationship between the Weibull parameters and the tensile strength of fiber bundles of different lengths. Next, fiber bundles of varying lengths were selected for tensile strength testing. Finally, the Weibull parameters were calculated by substituting the test results into the formula. This method offers several advantages: First, compared to single fiber testing, this method eliminates the need to test a large number of individual fiber strength values, requiring only a few bundles of different lengths to be tested. The experimental equipment is both reliable and affordable. Second, unlike the traditional fiber bundle test, which involves testing both tensile strength and the F∼ε (or σ∼ε ) curve (including strain measurements), this method focuses solely on tensile strength. As a result, the testing equipment is simpler to operate, and time costs are reduced. Third, the data processing is straightforward, requiring only a few data points to be inputted into the formula. The Weibull parameters of fiber strength obtained through this method have been validated by multiple experiments conducted on fiber bundles of different lengths, confirming its accuracy and reliability.