Master Curve of CSR Strength

For composites, the time-dependent mechanical responses at a temperature T can be shifted onto the responses at a reference temperature based on the time-temperature superposition principle using the time-temperature shift factor. The time-temperature shift factor o,. (7) is defined by  

---

Hypothesis B states that the same time-temperature superposition principle applies for all three types of strengths (CSR, creep, and fatigue). This means that the shift factors for all three types of strength can be assigned the same value. The first master curve of CSR strength can then be constructed from the test results for various constant strain rates and temperatures. 

A prediction method for the creep strength, (t, from the master curve of the CSR strength using the linear cumulative damage law was presented in our previous publication. Let tfa) and tfa) be the CSR and creep failure time, respectively, for the stress a. Suppose that the material experiences a non-decreasing stress history a(t) for 0 < f < / where t is the failure time under this stress history. The linear cumulative damage law states... 

Figure 6.20 Results of the CSR tensile tests (left) and the master curve for tensile CSR strength...

The left hand side of Figure 5 shows the creep strength cr at three temperatures which are shifted using the shift factor for the CSR strength to the data at To= 50 °C on the right hand side. There, the dashed curve represents the master... 

---