Life Prediction of CFRP Laminates Based on Accelerated Testing Methodology
The accelerated testing methodology (ATM) developed by the authors is introduced for predicting the long-term life of CFRP laminates by using the static, creep and fatigue strengths of them measured at a short term and various temperatures. First, the tim
- PDF / 1,015,016 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 62 Downloads / 262 Views
Life Prediction of CFRP Laminates Based on Accelerated Testing Methodology Yasushi Miyano and Masayuki Nakada Abstract The accelerated testing methodology (ATM) developed by the authors is introduced for predicting the long-term life of CFRP laminates by using the static, creep and fatigue strengths of them measured at a short term and various temperatures. First, the time-temperature superposition principle (TTSP) held for the viscoelasticity of matrix resin is explained by using the viscoelastic model. Second, the master curves of these strengths of CFRP laminates in the wide range of failure time at a reference temperature are constructed using TTSP for the viscoelasticity of matrix resin. Third, the master curves of CFRP strengths are statistically formulated based on Christensen’s viscoelastic crack kinetic theory. Finally, the applicability of life prediction by ATM is discussed for various CFRP laminates and structures. Keywords Carbon fiber reinforced plastics • Durability • Life prediction • Viscoelasticity • Statistics
5.1
Introduction
Carbon fiber reinforced plastics (CFRP) has been used for the primary structures of airplanes, ships, automobiles and others, in which the high reliability should be kept during the long-term operation. Therefore, it is strongly expected that the accelerated testing methodology for the long-term life prediction of CFRP structures exposed under the actual environmental temperature, water and others will be established. The accelerated testing methodology (ATM) [1] was developed by authors for the prediction of long-term static, creep and fatigue strengths of CFRP laminates based on the time-temperature superposition principle (TTSP). Based on ATM, the long-term strengths for CFRP laminates can be predicted by measuring the short-term strengths at elevated temperatures. The applicability of ATM was confirmed for CFRP laminates combined with PAN based carbon fibers and thermosetting resins [2–4]. Furthermore, ATM was developed into the advanced ATM [5] in which the formulation for the master curves of time-temperature dependent strengths were performed based on Christensen’s theory which describes statistically the crack kinetics in viscoelastic body [6]. In this paper, the concept of ATM is introduced for predicting the long-term life of CFRP laminates by using the static, creep and fatigue strengths of them measured at a short term and various temperatures. First, the TTSP held for the viscoelasticity of matrix resin is explained by using the viscoelastic model. Second, the master curves of these strengths of CFRP laminates in the wide range of failure time at a reference temperature are constructed using TTSP for the viscoelasticity of matrix resin. Third, the master curves of CFRP strengths are statistically formulated based on Christensen’s viscoelastic crack kinetic theory. Finally, the applicability of life prediction by ATM is discussed for various CFRP laminates and structures.
5.2
Time-Temperature Superposition (TTSP)
Maxwell model shown in the left side of Fig
Data Loading...
