Ductile failure is characterised by:  Little or no elongation to failure  Cavity coalescence Dimples in the fracture surface A significant reduction in cross sectional area The component breaking into many pieces

Why does the tensile fracture occur suddenly?

Q1. (i) Initial strain Please enter your supplied question data Q1. (ii) Eo B (hr¹Pa-¹) n IVICUITO Fracture 0.003 Please enter your answers here Your Q1. (i) Answers: 4.60E-34 Q1. (ii) 3.2 Q2. o (Pa) σo (Pa) 780,000,000 Q3. t (hr) Q2. A component is made from a metal that is known to be viscoelastic and behaves according to a secondary creep rate equation with constants of B and n provided as your input values. If the component is subjected to a constant force that results in the initial strain of E provided to you, determine the design stress for a secondary creep life of 1,000 hrs before attaining a limiting strain, &, of 0.01. Q3. If the same component is subjected to a constant displacement that results in the value of initial stress, o, provided to you, calculate the time for the stress to reduce to 200MPa. Young's modulus of the bolt is E = 200GPa.

Why does the brittle fracture occur in a torsion test?

(a) A large medium carbon steel crane hook is thought to contain penny- shaped internal cracks. If the non-destructive test equipment used on the hook is not capable of detecting cracks smaller than 20 mm diameter, determine the fracture toughness required from this steel if the safety factor on stress is to be 2. The yield stress of the AISI 1045 grade steel is 1050 MNm². Note: For this crack geometry, the 'compliance function' Y in the Stress Intensity Factor (K)) may be taken as 1. (b) A surface crack of 2.5 mm depth and a certain length is found in a thick rectangularcomponent. The component is schedule to be repaired in 6 months. The component is subjected to zero to maximum stress of 340 MPa, 50 times per hour. It was known that for this component catastrophic failure occurs when the crack size reaches 12 mm in depth. Assuming that the crack geometrical shape (aspect ratio) remains constant during crack growth, will the component fail before repair? For the crack geometry, the…