method. Determination of JIC Strain energy release rate per unit fracture surface area is calculated by J-integral method which is a contour path integral around the crack tip where the path begins and ends on either crack surfaces. J-toughness value signifies the resistance of the material in terms of amount of stress energy required for a crack to grow. JIC toughness value is measured for elastic-plastic materials. Now the single-valued JIC is determined as the toughness near the onset of the ductile crack extension (effect of strain hardening is not important). The test is performed with multiple specimen loading each of the specimen to various levels and unloading. This gives the crack mouth opening compliance which is to be used to get crack length with the help of relationships given in ASTM standard E 1820, which covers the J-integral testing. Another way of measuring crack growth is to mark the specimen with heat tinting or fatigue cracking. The specimen is eventually broken apart and the crack extension is measured with the help of the marks. The test thus performed yields several Load vs Crack Mouth Opening Displacement (CMOD) curve, which are used to calculate J as following:- The linear elastic J is calculated using and K is determined from where BN is the net thickness for side-grooved specimen and equal to B for not side-grooved specimen The elastic plastic J is calculated using Where =2 for SENB specimen bo is initial ligament length given by the difference between width and initial crack length APl is the plastic area under the load-displacement curve. Specialized data reduction technique is used to get a provisional JQ. The value is accepted if the following criterion is met Determination of tear resistance (Kahn tear test) The tear test (e.g. Kahn tear test) provides a semi-quantitative measure of toughness in terms of tear resistance. This type of test requires a smaller specimen, and can, therefore, be used for a wider range of product forms. The tear test can also be used for very ductile aluminium alloys (e.g. 1100, 3003), where linear elastic fracture mechanics do not apply. Standard test methods A number of organizations publish standards related to fracture toughness measurements, namely ASTM, BSI, ISO, JSME. ASTM C1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature ASTM C1421 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature ASTM