Fundamentals and certain problems of fatigue fracture mechanics

1987 ◽  
Vol 23 (5) ◽  
pp. 454-464 ◽  
Author(s):  
S. Ya. Yarema
Keyword(s):  
Fracture Mechanics ◽  
Fatigue Fracture

Analysis on the Fatigue Life of Asphalt Pavement under Traffic Flow Loads

2013 ◽  
Vol 361-363 ◽  
pp. 1727-1734
Author(s):  
Meng Qi Gao ◽  
Ping Ying Wang ◽  
He Ping Ding
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Fatigue Fracture ◽  
Fatigue Damage ◽  
Asphalt Pavement ◽  
Ansys Software ◽  
Element Analysis ◽  
Damage Area ◽  
Traffic Loads ◽  
Damage Rule

To study the fatigue life of asphalt pavement under traffic loads, a 3-D finite element analysis (FEA) Visio-elastic road model was established on the layered theory with ANSYS software. The fatigue damage was calculated with the maximum horizontal tensile strain of asphalt layer bottom based on the fatigue fracture mechanics, when single axis went across. Then the fatigue life was obtained after the fatigue damage occurred in some degree by the Miners linear cumulative damage rule. The results show that it taken 3.4 years when the damage area reached 10% of wheel path area, and 4.5years when reached 45%; while the calculated result was 5.5 years by axial-load conversion method. The analysis shows that the fatigue life of asphalt pavement calculated by fatigue fracture mechanics rule has more significance in practice.

A Procedure for Verifying the Structural Integrity of an Existing Pressurized Wind Tunnel

1974 ◽  
Vol 96 (4) ◽  
pp. 283-291
Author(s):  
J. T. Taylor ◽  
P. E. Lewis ◽  
J. W. Ramsey
Keyword(s):  
Wind Tunnel ◽  
Fracture Mechanics ◽  
Fatigue Fracture ◽  
Structural Integrity ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Cyclic Life ◽  
Working Pressure ◽  
Test Pressure ◽  
Non Destructive

This paper describes the application of material test, stress-fatigue-fracture mechanics analyses, nondestructive examinations and repairs to verify the structural integrity and the remaining cyclic life in a large pressurized wind tunnel (65,000 ft3) (1840 m3). The tunnel with pressures up to 135 psig (0.93 MPa) was constructed in 1940 and has been in service to the present date. The only record of a non-destructive examination conducted on the vessel prior to this evaluation was a hydrostatic test-pressure at 1 1/2 times the maximum working pressure. The material tests were performed on a sample of material (A-70 steel) cut from the tunnel shell. These tests included fracture toughness (R-curve, Kc) as determined from a compact tension specimen, crack growth rate (da/dn vs ΔK), Charpy V-notch, dynamic tear (from which the nil-ductility temperature was determined), and tensile and chemical tests. The results and applications are presented and discussed. Stress analyses include computer programs based on finite element and numerical integration techniques. Fatigue analyses incorporating a fatigue reduction or stress amplification factor to account for a small flaw existing in a weld are presented. Fracture mechanics analyses of the tunnel shell were performed for (1) the general membrane regions, (2) regions of high bending stress, and (3) areas at tunnel penetrations. The critical flaw sizes at each location are determined. The use of the “leak before break” criterion is discussed. The non-destructive examinations (radiograph, ultrasonic, sonic, and magnetic particle) to verify the assumptions of fatigue-fracture mechanics analyses and ASME Code applications are documented. Penetrations in the tunnel shell that were fatigue limited are shown “before” and “after” repair. The remaining cyclic life as obtained by the fatigue-fracture mechanics analyses and the operating envelope which resulted from these studies for metal temperature vs pressure was determined to be approximately 10 years.

A new approach in testing fatigue fracture mechanics properties in asymmetrical bonded composite/metal assemblies

2019 ◽  
Vol 158 ◽  
pp. 390-399 ◽  
Author(s):  
G. Zambelis ◽  
T. Da Silva Botelho ◽  
O. Klinkova ◽  
I. Tawfiq ◽  
C. Lanouette
Keyword(s):  
Fracture Mechanics ◽  
Fatigue Fracture ◽  
New Approach ◽  
Bonded Composite
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