A structural component is fabricated from a Ti-6AI-4W titanium alloy that has a plane-strain fracture toughness of 74 MPavm. It has been determined that this component fails at a stress of 250 MPa when the maximum length of a surface crack is 2.2 mm. It found in another part same material that has a surface crack of X mm. and the stress load of 175 MPa. How big (crack length) X must be? Note:

A component made of 7075-T6 aluminum alloy has an edge crack of 1.4 mm in length. Plane strain fracture toughness of this alloy is given as 27 MPavm. Geometrical factor of the crack is given as 1.2. (a) If this alloy is subjected to uniaxial tensile stress of 380 MPa, determine whether sudden brittle fracture occurs or not. (b) Calculate the maximum allowable crack size for this component in order not to be failed in brittle manner under a stress of 1000 MPa (Density of steel 7.85 g/cm³, 9.80665 N = 1 kg). Modulus of elastisity, GPa Ultimate tensile Yield strength, Alloy strength, MPa MPa 2014 Al alloy Bronze (92Cu-8Sn) High carbon steel Pure Titanium 97 186 380 72 110 152 380 615 215 240 330 107

A Plexiglas model of a gear has a 1 mm crack formed in its fillet curve (where the tensile stress is maximum). The model is loaded until the crack starts to propagate. Y=1.5. How much higher a lod can a gear (made of AISI 4340 steel tempered to 425°C) carray with the same crack and the same geometry?

The flexural (or fracture) strength of brittle materials may be determined using a variation ofEquation 8.1. Compute the critical crack tip radius (row sub t in nm) for an Al2O3 specimen thatexperiences tensile fracture at an applied stress (sigma initial) of 275 MPa. Assume a critical surfacecrack length (a) of 2 * 10^-3 mm and a theoretical fracture strength of E/10, where E is themodulus of elasticity (393 GPa). Note, fracture will occur when sigma sub m reaches the theoreticalfracture strength of the material.given equation:  sigma sub n = 2*sigma initial*sqrt(a/row sub t)

Q1/ Air craft component is fabricated from epoxy composites that have plane strain fracture toughness of (20 MPa m2). It has been determined that fracture results at a stress of (250 MPa) when the maximum (or critical) internal crack length is (3 mm). For the same component and part, will fracture occur at a stress level of (350 MPa) when the maximum internal crack length is (2 mm)? yes or not depending on your solution? Q2/ Polymer (y) has possion ratio (0.33) it faced shearing forces leading to change the shape of the polymer (y) sample. Where the dimensions of sample are (h = 0.8 cm, x = 1 cm) and (Ax = 0.4 cm) and the shear force is 0.25 KN. Calculate the elastic modulus and the bulk modulus?

The fuselage of an airliner can be considered as a thin-walled tubeinternally pressurized with a diameter of 7 m and a thickness of 3 mm. It is made withAluminum sheets with K ic fracture toughness of 100 MPa m1/2. At cruising altitudeinternal pressure gauge shows 0.0.Mn/m2.. In a horizontal row rivets have beencaused many fatigue cracks and have joined together to form a longitudinal crack thatit goes through the thickness of the fuselage. Estimate the critical length for this crack to propagate,causing the fuselage to break. (The pressure in a tube is resolved into a tension in the wallfrom ? = p r / t, where p = pressure, r = radius, t = thickness

In the Table below Data for Mar M 247-a Nickel base superalloy is shown. (1) Plot the steady state strain rate and time to rupture to predict a relationship between the two variables. Provide an equation for the relationship that you see. (2) Give an explanation as to why the fracture elongation is going up with stress.

A large plate is fabricated from a steel alloy that has a plane strain fracture toughness of 55 MPa√m. If during service use, the plate is exposed to a tensile stress of 200 MPa, compute the minimum length of a surface crack that will lead to a fracture. Assume the value of 1.0 for Y.

A tie rod made of quenched and tempered 4340 steel is used as a critical linkage in an industrial apparatus. The rod is subjected to an alternating cyclic tensile/compressive stress from 550 MPa to -550 MPa. An inspection of the rod revealed a 3.5 mm deep edge crack on the surface of the rod. Please answer the following question for the rod given the properties in the table and curve below and fracture toughness of 55 MPa√m. (NOTE: Y=1.12 for edge crack and use “a” not “2a” for the length of the crack)  1. What is the minimum crack size that would cause instantaneous fast fracture at the current maximum axial tensile loading, assuming plane strain conditions apply? If the resolution limit of the flaw detection apparatus were 1.5 mm, would this flaw be subject to detection? Show calculations to back up your conclusions.

A tie rod made of quenched and tempered 4340 steel is used as a critical linkage in an industrial apparatus. The rod is subjected to an alternating cyclic tensile/compressive stress from 550 MPa to -550 MPa. An inspection of the rod revealed a 3.5 mm deep edge crack on the surface of the rod. Please answer the following question for the rod given the properties in the table and curve below and fracture toughness of 55 MPa√m. (NOTE: Y=1.12 for edge crack and use “a” not “2a” for the length of the crack)  1. At the given crack size and tensile loading would the rod undergo instantaneous fast fracture, assuming plane strain conditions? Show calculations to back up your conclusions.