Experimental determinations of high temperature crack growth

Methods of obtaining crack growth data at elevated temperatures are broadly similar to those used to determine the uniaxial creep data described in Chapter 2. A typical arrangement is shown in Fig. 7.1. A cracked test specimen is inserted in a furnace capable of maintaining a uniform and constant temperature. A constant load is applied and the crack length, as monitored by one of the methods described in section 7.2, and the load-line displacement are measured as functions of time during the test. These measurements are used to determine C* and thus to provide crack growth rate as a function of C*. Subject to the satisfaction of validity criteria the experimental data may then be applied to structural assessments of the type described in Chapter 8.