Concept explainers
A large, flat plate is subjected to constant-amplitude uniaxial cyclic tensile and compressive stresses of 120 and 35 MPa, respectively. If before testing the largest surface crack is 1.00 mm and the plain-strain fracture toughness of the plate is
Want to see the full answer?
Check out a sample textbook solutionChapter 7 Solutions
Foundations of Materials Science and Engineering
Additional Engineering Textbook Solutions
Engineering Mechanics: Statics
Thermodynamics: An Engineering Approach
HEAT+MASS TRANSFER:FUND.+APPL.
Engineering Mechanics: Dynamics (14th Edition)
Statics and Mechanics of Materials
Applied Statics and Strength of Materials (6th Edition)
- Help me pleasearrow_forwardA specimen of a steel alloy with a plane strain fracture toughness of 22.1 MPavm. The largest surface crack is 0.6 mm long? Assume that the parameter Y has a value of 0.5. What is the critical stress in MPa. Write your answer with 2 decimal places. Answer: 0 dºvo vo (0) 00 00, GMarrow_forwardEstimate the theoretical fracture strength of a brittle material if it is known that fracture occurs by the propagation of an elliptically shaped surface crack of length 0.7 mm and having a tip radius of curvature of 0.004 mm, when a stress of 1046MPa is applied. Your answer must be in GPa. Write your answer to 1 decimal place. Answer: 0 √ Vo (88) + TI a Farrow_forward
- What is the magnitude of the maximum stress that exists at the tip of an internal crack having a radius of curvature of 1.9 x 10" mm and a crack length of 3.8 x 10 mm when a tensile stress of 140 MPa is applied? 4. 5. A ceramic matrix composite contains internal flaws as large as 0.001 cm in length. The plane strain fracture toughness of the composite is 45 and the tensile strength is 550 MPa. Will the flaw cause the composite to fail before the tensile strength is reached? Assume that Y 1 A cylindrical rod 500 mm long, having a diameter of 12.7 mm, is to be subjected to a tensile load. If the rod is to experience neither plastic deformation nor an elongation of more than 1.3 mm. when the applied load is 29,000 N, which of the four met ls or alloys listed below are possible cardidates? Justify your choice(s). Materia! Modulus of Yield Tensiie Strength (MPa) Elasticity(GPa) Strength(MPa) Aluminium alloy 70 255 420 Brass alloy 100 345 420 Сopper 110 210arrow_forwardA plate with width w = 90 mm and thickness t = 5 mm carries a uniformly distributed tensile force P = 30 kN in longitudinal direction. The plate has an external transverse crack with length of 18 mm. To prevent sudden fracture, calculate the minimum required critical stress intensity factor (KIc) for mode I (in MPa.m1/2) for the plate material. Assume a safety factor of n = 2.4.arrow_forwardQu2. (A) What is fatigue? Mention the sequence of steps involved in fatigue of a smooth specimen. Mention Four (4) factors that affect fatigue of smooth specimens, stating how each affects fatigue life (B) A very wide panel made of a material of plane-strain fracture toughness of Kic=55MPaVm was found to have a central crack of size 2.5mm. It is subjected to cyclic loading at a design (or working) stress of 690MPA and stress ratio of zero. (a) Sketch the stress-time graph of the loading cycle and determine (i) Stress Range, (ii) maximum cycle stress, (iii) stress amplitude and (iv) mean stress (b) Will the initial loading cycle cause the panel to fracture? Why or whynot? Compute the maximum allowable fatigue flaw size that can fracture the panel during the cyclic loading. (Assume that plain strain condition prevails). (c)arrow_forward
- A structural beam is built from steel with a yield strength of 345 MPa. The structure has a minimum service temperature of 5 oC, where the fracture toughness of the steel KIC = 60 MPam. What is the minimum surface crack lengths that must be detected by quality control to ensure that the full yield strength of the steel is available in the beam? Assume geometric parameter Y = 1 and plain strain conditions. Answer in millimeters.arrow_forwardA three-point bending test is conducted on a cylindrical specimen of aluminum oxide (E=400 GPa, Kıc=4 MPavm). This specimen has a surface crack of P um (unit in um) deep at tensile face where the maximum tensile stress occurs. If the specimen radius is 5.0 mm and the support point separation distance is 50.0 mm, predict whether or not you would expect the specimen to fracture when a load of 1000 N is applied?arrow_forwardA mild steel tensile specimen of initial length 44 mm and initial diameter 6.4 mm is subjected to a tensile test and the following data are obtained. - Yield Strength as 88 MPa - Maximum Strength as 212 MPa - Fracture Strength as 152 MPa - Percentage of Elongation as 63 % - Percentage of Reduction in area as 39% Determine the Fracture load The Final length in mm = The Final area in mm2 =arrow_forward
- A tensile test for a copper specimen has been performed and the following data are obtained. - Percentage of Elongation = 69 % - Percentage of Reduction in Area = 39 % - Final length after fracture = 35.5 mm - Final Diameter after fracture = 3.6 mm & - Ultimate stress = 396 MPa SOLUTION: i) Initial Length (in mm) = ii) Final Area (in mm2) = iii) Initial Area (in mm2) =arrow_forwardspecimen of a 4340 steel alloy with a plane strain fracture toughness of 54.8 MPa√m is exposed to a stress of 1030 MPa. Will this specimen experience fracture if it is known that the largest surface crack is 0.5 mm long? Why or why not? Assume that the parameter Y has a value of 1.0.arrow_forwardsmall crack, 4mm deep, is found on the edge of a large, thick plate structure. The plate is continuously subjected to a uniform cyclic tensile stress (in the direction perpendicular to the crack plane) which varies from 0 MPa to 100 MPa and back to 0 MPa every 40 seconds. If the next inspection is to take place in 30 days, would it be safe to delay the replacement or repair of the plate until that time? The stress intensity factor, KI, for this type of crack is related to the nominal stress, G, and the crack length, a, via the relationship is K, = 1.12a Va %3D For the plate material, the yield stress is 800 MPa, the fracture toughness is 50 MN/m2 and threshold stress intensity factor range is 6 MN/m3/2, The fatigue-crack growth rate per cycle for the material, da/dN, can be defined by: 3/2 da / dN = 2.8 x 10-12 (AK,) ^PY (m/cycle) Where AK1 has unit MN/m e 8:34 /arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY