Transient Analysis on Reflective Crack of Highway Semi-Rigid Pavement Caused by Temperature Change

2017 ◽  
Vol 744 ◽  
pp. 163-168
Author(s):  
Shang Yang Yang ◽  
Xi Guang Gao ◽  
Long Yun Zhang
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Surface Layer ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Surface Crack ◽  
Crack Tip ◽  
Base Layer ◽  
The Road

The asphalt surface crack fracture mainly includes load cracks and non-load cracks. The former is due to the weight of the vehicle itself causing excessive fatigue weight, therefore, this crack is also known as road load fatigue crack. Non-load crack is affected by nature factors such as temperature and humidity, which makes the road structure cracking. In this paper, finite element method is used to analyze the transient temperature field, and on this basis, the temperature stress simulation of pavement structure is carried out. The stress intensity factor of asphalt surface crack tip is analyzed by finite element method. The results show that the modulus of the surface and the base layer and the increase of the temperature coefficient of the base layer will lead to the increase of the stress intensity factor of the crack tip. The temperature coefficient of the surface layer has no obvious effect on the stress intensity factor. In addition, increasing the thickness of the surface layer can effectively reduce the stress intensity factor at the crack tip. The paper also concludes that the gravel base can effectively slow down the expansion of the road refection crack.

Analysis on the Expansion of Surface Crack in Asphalt Pavement

2011 ◽  
Vol 250-253 ◽  
pp. 3069-3073
Author(s):  
Pei Juan Lu ◽  
Jie Yang ◽  
Cong Bin Huang
Keyword(s):  
Stress Intensity Factor ◽  
Surface Layer ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Surface Crack ◽  
Crack Depth ◽  
Great Influence ◽  
Base Layer ◽  
Finite Element Models ◽  
The Relationship

The relationship between surface crack tip stress intensity factor and calculated parameters of pavement structure is discussed and finite element models based on the fracture mechanics theory is created. From the study in this paper, the following conclusions can be drawn: As the load increases, stress intensity factor will decrease, and it may promote spread of the crack. Surface layer modulus has a great influence on stress intensity factor. In the condition of the same crack depth, stress intensity factor increases while surface layer modulus increases, stress intensity factor decreases gradually while the thickness of the surface layer increases. As base layer modulus increasing, stress intensity factor of surface layer decreases. With the increase of the modulus of subbase layer, stress intensity factor of surface layer decreases gradually. The earthen foundation module has a little big influence. With the increase of the earthen foundation module, stress intensity factor will decrease, so it can delay the appearance of the crack.

Application of Extended Finite Element Method (XFEM) to Stress Intensity Factor Calculations

2015 ◽  
Author(s):  
Do-Jun Shim ◽  
Mohammed Uddin ◽  
Sureshkumar Kalyanam ◽  
Frederick Brust ◽  
Bruce Young
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Degrees Of Freedom ◽  
Extended Finite Element Method ◽  
Partition Of Unity ◽  
Extended Finite Element ◽  
Element Method

The extended finite element method (XFEM) is an extension of the conventional finite element method based on the concept of partition of unity. In this method, the presence of a crack is ensured by the special enriched functions in conjunction with additional degrees of freedom. This approach also removes the requirement for explicitly defining the crack front or specifying the virtual crack extension direction when evaluating the contour integral. In this paper, stress intensity factors (SIF) for various crack types in plates and pipes were calculated using the XFEM embedded in ABAQUS. These results were compared against handbook solutions, results from conventional finite element method, and results obtained from finite element alternating method (FEAM). Based on these results, applicability of the ABAQUS XFEM to stress intensity factor calculations was investigated. Discussions are provided on the advantages and limitations of the XFEM.

Modelling shattered rim cracking in railroad wheels

2011 ◽  
Vol 225 (6) ◽  
pp. 593-604
Author(s):  
V Sura ◽  
S Mahadevan
Keyword(s):  
Residual Stress ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress State ◽  
Intensity Factor ◽  
Residual Stresses ◽  
Equivalent Stress ◽  
Crack Tip ◽  
Residual Stress State

Shattered rim cracking, propagation of a subsurface crack parallel to the tread surface, is one of the dominant railroad wheel failure types observed in North America. This crack initiation and propagation life depends on several factors, such as wheel rim thickness, wheel load, residual stresses in the rim, and the size and location of material defects in the rim. This article investigates the effect of the above-mentioned parameters on shattered rim cracking, using finite element analysis and fracture mechanics. This cracking is modelled using a three-dimensional, multiresolution, elastic–plastic finite element model of a railroad wheel. Material defects are modelled as mathematically sharp cracks. Rolling contact loading is simulated by applying the wheel load on the tread surface over a Hertzian contact area. The equivalent stress intensity factor ranges at the subsurface crack tips are estimated using uni-modal stress intensity factors obtained from the finite element analysis and a mixed-mode crack growth model. The residual stress and wheel wear effects are also included in modelling shattered rim cracking. The analysis results show that the sensitive depth below the tread surface for shattered rim cracking ranges from 19.05 to 22.23 mm, which is in good agreement with field observations. The relationship of the equivalent stress intensity factor (Δ K eq) at the crack tip to the load magnitude is observed to be approximately linear. The analysis results show that the equivalent stress intensity factor (Δ K eq) at the crack tip depends significantly on the residual stress state in the wheel. Consideration of as-manufactured residual stresses decreases the Δ K eq at the crack tip by about 40 per cent compared to that of no residual stress state, whereas consideration of service-induced residual stresses increases the Δ K eq at the crack tip by about 50 per cent compared to that of as-manufactured residual stress state. In summary, the methodology developed in this article can help to predict whether a shattered rim crack will propagate for a given set of parameters, such as load magnitude, rim thickness, crack size, crack location, and residual stress state.

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