A METHOD TO SELECT LARGE SCALE REPAIR SECTIONS OF EXPRESSWAY VIADUCTS BASED ON INITIATION AND PROPAGATION PROCESSES OF FATIGUE CRACKS ON STEEL SLABS

2021 ◽  
Vol 77 (1) ◽  
pp. 37-56
Author(s):  
Yohei NINOMIYA ◽  
Daijiro MIZUTANI ◽  
Mitsuru JIDO ◽  
Kiyoyuki KAITO ◽  
Kiyoshi KOBAYASHI ◽  
...  
Keyword(s):  
Large Scale ◽  
Fatigue Cracks ◽  
Initiation And Propagation ◽  
Steel Slabs

Fatigue Testing of Large-Scale Models of Submarine Structural Details

1965 ◽  
Vol 2 (03) ◽  
pp. 299-307
Author(s):  
Frank W. Dunham
Keyword(s):  
Cyclic Loading ◽  
Large Scale ◽  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Pressure Variation ◽  
Test Tank ◽  
Initiation And Propagation ◽  
Scale Models ◽  
Structural Details

The conversion of a 30-ft-dia test tank to a facility for subjecting large-scale models of submarine structural details to cyclic loading is described. By means of automatically controlled valves, models were subjected to a pressure variation simulating a submarine diving to its test depth and returning to the surface. The cyclic rate was slightly less than one per minute. The system was so designed that the test tank itself was not subjected to the pressure variations. Details of a series of models designed to simulate particular structural details of interest in recent submarine construction are described. Results of the tests to date are summarized, and several observations relative to the initiation and propagation of fatigue cracks in submarine structural details are presented.

Fracture Toughness of Thick Steel Plates for Shipbuilding

2008 ◽  
Vol 580-582 ◽  
pp. 89-92
Author(s):  
Joon Sik Park ◽  
B.Y. Jung ◽  
Hiroshi Yajima ◽  
Jong Bong Lee
Keyword(s):  
Fracture Toughness ◽  
Crack Initiation ◽  
Large Scale ◽  
Steel Plate ◽  
Plate Thickness ◽  
Steel Plates ◽  
Initiation And Propagation ◽  
Thick Steel ◽  
Test Result ◽  
Grade Steel

In this study, the effect of thickness on the fracture toughness of the steel plate with the thickness of 80mm has been investigated by the wide plate tensile test and ESSO test. The fracture toughness for crack initiation and propagation was evaluated quantitatively for the full thickness specimen. It was found that EH-36 grade steel with the thickness of 80mmt showed the KIC value of 164kgf/mm1.5 at -145°C. Also, large-scale ESSO test result showed that the steel with the thickness of 80mm had 520kgf/mm1.5 at -10°C. Although it was known that the fracture toughness decreases with the increase of the plate thickness, EH-36 grade steel with the thickness of 80mm had enough values of fracture toughness to prevent the crack initiation and arrest the brittle crack propagation.

Investigation of Residual Stresses in a Sleeve Coldworked Lug Specimen by Neutron and X-ray Diffraction

1994 ◽  
Vol 38 ◽  
pp. 455-461
Author(s):  
R. Lin ◽  
B. Jaensson ◽  
T. M. Holden ◽  
R. B. Rogge ◽  
J. H. Root
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Cracks ◽  
Fatigue Properties ◽  
Aircraft Industry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initiation And Propagation ◽  
Structural Parts ◽  
Compressive Residual Stresses

Sleeve coldworking (SCW) is a mechanical process used in the aircraft industry to strengthen fastener holes of structural parts. By cold-expanding the holes, compressive residual stresses and a high dislocation density are introduced around the holes, the effect of which is to counteract the initiation and propagation of fatigue cracks and thus increase the fatigue life of the parts. The knowledge of residual stress due to SCW is therefore crucial for assessing the fatigue properties of a treated part. In this study, residual stresses were investigated, by employing neutron and X-ray diffraction methods, in a lug specimen that was sleeve coldworked and fatigued. The specimen had been used for testing the influence of the SCW process on fatigue life and crack propagation behaviour under constant amplitude or variable amplitude cyclic loading.

Experimental and Analytical Studies on the Effect of Excessive Loading on Fatigue Crack Propagation in Piping Materials

2009 ◽  
Author(s):  
Yoshihito Yamaguchi ◽  
Jinya Katsuyama ◽  
Kunio Onizawa ◽  
Hideharu Sugino ◽  
Yinsheng Li ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Large Scale ◽  
Fatigue Cracks ◽  
Plastic Region ◽  
Retardation Effect ◽  
Seismic Motion ◽  
Loading Patterns ◽  
Piping Systems

The seismic regulatory guide was revised in September 2006 and the Niigata-ken Chuetsu-oki earthquake, whose magnitude was beyond the design base seismic motion, occurred in July 2007. Due to these events, attention is being drawn to the evaluation of the effects of large scale earthquakes for some piping systems in which SCC and/or fatigue cracks may potentially occur. Many papers have been already published about the retardation effect that excessive loading has on fatigue crack growth. The retardation effect is treated qualitatively in regard to the plastic strain generated by excessive loading. In this work, crack growth after excessive loading is evaluated for carbon steel and austenitic stainless steel. Some cyclic excessive loading patterns such as stepwise increases or decreases were applied to fatigue crack growth experiments. The FEM analyses were conducted to evaluate the plastic region size during these loading conditions. PFM analyses were performed to evaluate the extent to which the retardation of crack growth influences the probability of failure.

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