Statistical Fatigue Failure Time of Unidirectional CFRP under Compression Loading
Abstract
The developed accelerated testing methodology (ATM) based on the matrix resin viscoelasticity for the creep and fatigue failure life prediction of fiber reinforced polymers (FRP) was applied to the statistical prediction of long-term creep and fatigue failure life for the longitudinal bending of unidirectional CFRP laminates which is an important basic item for the durability design of CFRP structures used for aircraft and others. The validity of our developed ATM for this creep and fatigue life prediction under the longitudinal bending of unidirectional CFRP was discussed herein. From that discussion, the following results were obtained.1. Formulation of the statistical creep and fatigue failure time under bending load for the longitudinal direction of unidirectional CFRP based on the viscoelasticity of matrix resin was established assuming micro-buckling failure near the loading point.2. The master curve of relaxation modulus of matrix resin in the very wide range of time was constructed by application of the time temperature superposition to the data of DMA and creep tests measured at various temperatures.3. Statistical creep failure times under bending loads at an arbitrary temperature were predicted by substituting the statistical flexural static strengths of unidirectional CFRP measured at several temperatures and the relaxation modulus of matrix resin into the formulation. Predicted statistical creep failure times agreed well with the measured ones. Then, the validity of our developed ATM for creep life prediction under the longitudinal bending of unidirectional CFRP was established.4. Statistical fatigue failure times under bending loads at various temperatures were measured and it was confirmed that the master curve of flexural fatigue strength as the function of number of cycles to failure can be constructed based on the concept of ATM.5.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 20, 2022
- Accession Number
- AD1170069
Entities
People
- Masayuki Nakada
- Yasushi Miyano
Organizations
- Kanazawa Institute of Technology