On the Computation of a Generalised Dynamic J-Integral and its Application to the Durability of Steel Structures

2009 ◽  
pp. 121-132
Author(s):  
Ingbert Mangerig ◽  
Stefan Kolling
Keyword(s):  
Steel Structures ◽  
J Integral ◽  
Dynamic J Integral

Coating Life Assessment: The Use of Adhesion Strength in Parametric Development in Coating Degradation Evaluation

2012 ◽  
Vol 488-489 ◽  
pp. 427-431
Author(s):  
Yunan Prawoto ◽  
Azizi Mat Yajid ◽  
Zaini Ahmad
Keyword(s):  
Adhesion Strength ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Steel Structures ◽  
Industrial Applications ◽  
Organic Coating ◽  
Life Assessment ◽  
Sufficient Information ◽  
J Integral ◽  
Degradation Evaluation

Most of the steel structures used in industrial and non-industrial applications are exposed to outdoors weathering conditions. Organic coating typically protects them from corrosion. The maintenance actions can be done efficiently only if there is sufficient information of the condition. Therefore, the deterioration of the coating system and its lifetime has to be assessed accurately. This paper focuses on the development of parameters based on adhesion strength useful for that purpose. Three parameters are proposed, namely stress intensity factor, strain energy density, and J-integral.

Effect of Geometry Factors on Dynamic Fracture Behavior for Mechanical Heterogeneous Welded Joint

2006 ◽  
Vol 324-325 ◽  
pp. 543-546
Author(s):  
Fu Qiang Tian ◽  
Xiao Yan Li ◽  
Yao Wu Shi
Keyword(s):  
Weld Metal ◽  
Strain Rate ◽  
Crack Length ◽  
Dynamic Fracture ◽  
Welded Joint ◽  
Initial Crack ◽  
J Integral ◽  
Computation Model ◽  
Initial Crack Length ◽  
Dynamic J Integral

Welded joint is a mechanical heterogeneous body, which is composed of base metal, weld metal and heat affected zone (HAZ). Many welded structures endure dynamic load in service. Mechanical heterogeneity has important influence on dynamic fracture behaviour of welded joint. In the present investigation, dynamic fracture parameter of J-integral of undermatched three-point-bending (TPB) welded joint specimens containing longitudinal crack with different geometry were computed. The strain rate near crack tip reaches 103 under the impact velocity of 5m/s, so dynamic properties under corresponding strain rate should be used in dynamic analysis. The results of instrumented impact experiment were used as the input parameters in the computation. Dynamic J-integral was evaluated using virtual crack extension (VCE) method of MARC finite element code in 3-D condition. Dynamic J-integral evaluated by VCE method is path independent. The value of dynamic J-integral curve increases with loading time smoothly, so inertia force has little influence on dynamic J-integral. The values of dynamic J-integral decrease with increase of weld width. When the weld width is bigger than 5mm the influence of base material on weld metal is not evident. The influence of initial crack length on dynamic J-integral is complicate. The value of dynamic J-integral of the computation model with initial crack length of a/W=1/4 is the highest, and that of the computation model with initial crack length of a/W=1/8 is the lowest. The results are helpful for dynamic fracture evaluation of macro-heterogeneous welded joints.

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