48 research outputs found
Elucidating fault-related fold mechanics: a 2D finite element analysis of bending, slip, and buckling mechanisms
Get PDFFault-related folds are present in most tectonic settings and may serve as structural traps for hydrocarbons. Due to their economic importance, many kinematic models present for them. Unfortunately, most of them have predominantly concentrated on the sliding mechanism parallel to the layering and often ignore the integral role of buckling in folding processes. This study is at the forefront of exploring the interplay among, sliding, buckling, and bending in the formation of the three fundamental types of fault-related folds: detachment, fault-propagation, and fault-bend folds. To this end, we developed five sets of two-dimensional (2D) finite element models, embodying both elastic and elasticplastic behaviors. Our results indicate that sliding parallel to layering and faults, in conjunction with buckling, are the predominant mechanisms in fault-related folding. The strain ellipse patterns in our models are consistent with those observed in buckling models, thus affirming the significance of buckling in these geological structures. Furthermore, our models demonstrate that fault slip diminishes from the periphery towards the center in all three types of fault-related folds, in contrast to interlayer slip, which intensifies from the edge towards the center. In essence, a diminution in fault slip at the center is balanced by an augmentation in interlayer slip, leading to thickening and buckling. The genesis of all three fault-related fold types is attributed to the reduction in fault slip, with their distinctiveness defined by the location of this reduction: at the detachment fault tip for detachment folds, at the ramp tip for faultpropagation folds, and at the upper flat for fault-bend folds
Elucidating fault-related fold mechanics: a 2D finite element analysis of bending, slip, and buckling mechanisms
Get PDFFault-related folds are present in most tectonic settings and may serve as structural traps for hydrocarbons. Due to their economic importance, many kinematic models present for them. Unfortunately, most of them have predominantly concentrated on the sliding mechanism parallel to the layering and often ignore the integral role of buckling in folding processes. This study is at the forefront of exploring the interplay among, sliding, buckling, and bending in the formation of the three fundamental types of fault-related folds: detachment, fault-propagation, and fault-bend folds. To this end, we developed five sets of two-dimensional (2D) finite element models, embodying both elastic and elastic-plastic behaviors. Our results indicate that sliding parallel to layering and faults, in conjunction with buckling, are the predominant mechanisms in fault-related folding. The strain ellipse patterns in our models are consistent with those observed in buckling models, thus affirming the significance of buckling in these geological structures. Furthermore, our models demonstrate that fault slip diminishes from the periphery towards the center in all three types of fault-related folds, in contrast to interlayer slip, which intensifies from the edge towards the center. In essence, a diminution in fault slip at the center is balanced by an augmentation in interlayer slip, leading to thickening and buckling. The genesis of all three fault-related fold types is attributed to the reduction in fault slip, with their distinctiveness defined by the location of this reduction: at the detachment fault tip for detachment folds, at the ramp tip for fault-propagation folds, and at the upper flat for fault-bend folds
Experimental analysis and theoretical predictions of the limit strains of a hot-dip galvanized interstitial-free steel sheet
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A methodology for determination of extended strain-based forming limit curve considering the effects of strain path and normal stress
No full textFINITE ELEMENT MODELING OF FATIGUE CRACK GROWTH IN CORRODED PIPELINE
No full textEnsuring the safety of pipelines in the oil and gas industry is important to
prevent financial losses and human injuries. One of the threats of pipelines is
corrosion effects and it may occur locally and by repeating changes in loading
and operation pressure conditions, it could lead to the phenomenon of fatigue
in corroded pipelines. In this research, the corrosion of the inner surface of
the API 5L Gr. x52 pipeline using ASME B31.G. and the finite element method was
studied and the obtained results along with experimental results were compared.
It was found that the effective area method of ASME B31.G. with a maximum error
of 3.83\% compared to the FEM had good compatibility with the FEM and the
laboratory method. Then, by taking into account the phenomenon of fatigue due
to working pressure changes, crack growth due to both fatigue and corrosion was
studied simultaneously by theoretical methods and extended finite element
method. The effect of various factors and conditions on the formation and crack
growth due to fatigue by considering the effects of corrosion on the inner
surface of the pipeline using XFEM was investigated. By the failure pressure of
corroded pipelines, the fatigue crack growth would be investigated and by
obtaining stress intensity factors using Paris law and XFEM, results would be
investigated in terms of important factors in the fatigue crack growth and the
significance and effect of depth and length of cracks on the stress intensity
factors will be detected by the results of XFEM. Using the results, the effects
of various factors such as corrosion area characteristics, crack geometry
including crack depth, crack length, and fluctuations in fluid working conditions including work pressure in fatigue crack growth were investigated. In the model 61\%, the first mode of the stress intensity factor of the theoretical method with an error of 0.43\% compared to the XFEM showed good agreement with the results of the theoretical methods and the XFEM in the field of fatigue crack growth
NUMERICAL ANALYSIS OF GROWING THE DUCTILE DAMAGE IN STRUCTURES REINFORCED BY SMA USING CONTINUUM DAMAGE MECHANICS APPROACH
No full textIn general, materials include micro-cracks and small holes which is created during the manufacturing process. The growth of these micro-cracks leads to degradation of mechanical properties and resulting in deterioration of the materials. Continuum damage mechanics is the new field of failure criteria which survey the behavior and responses of weakened material during the complete process of deterioration of material. This method defines the damage growth with an internal variable and can be used to predict the failure behavior of many materials such as metals, composites, polymers, and so on. Shape memory alloys have unique features, such as, having memorable properties, being super elastic and being energy absorber, which led to new applications in science and engineering research. Super elastic property accompanies with a lot of energy absorption during creating a Hysteresis loop. In this research, we examine mechanical behavior of materials reinforced with smart alloy in the context of environmental damage mechanics. Simulation and experimental results were very close. The considered structure is a notched piece of aluminum which is reinforced by the smart alloy. This material is notched because when the smart alloy reaches to its maximum reversible strain, damage variable reaches to its critical value due to the stress concentration. Accordingly, in this case, the effect of existence of the smart alloy is studied to find how it reduces the growing of the damage. Simulation of the mentioned structure is performed with Finite Element Analysis, where the structure was modeled under longitudinal loading. UMAT code of Lemaiter model, was developed for behavioral properties with damaged aluminum, UMAT code of Brinson model was used for behavioral properties of shape memory alloy. Simulation results suggest that different behavioral aluminum with aluminum reinforced by SMA. Existence of smart alloy on the aluminum substrate reduces the damage evolution and the structure fails in higher loadings. Also, the simulation results showed that reinforcing materials such as aluminum with shape memory alloys, up to the failure, are suitable choices for cyclic loading
The strain gradient approach for determination of forming limit stress and strain diagrams
No full textUterine horn intussusception in immediate post‐partum in a Pomeranian Spitz dog
No full textAbstract A 2‐year‐old Pomeranian‐Spitz dog (5.8 kg) was admitted with symptoms of uterine prolapse and lethargy 1 day after whelping three puppies. The prolapsed uterus was corrected, but the next day, prolapse reoccurred. To fix the cervix to the abdominal wall, the dog underwent a surgery operation where intussusception in the left horn of the uterus was found. Ovariohysterectomy was performed as the treatment of choice. The diagnosis of intussusception is challenging, and exploratory laparotomy is the reliable diagnostic approach. Although uterine intussusception is rare, it should be one of the important considerations in dogs within the post‐partum period
Molecular Dynamics Simulation of the Effects of the Carbon–Water Interaction Parameters on the Nanofluidic Energy Absorption System
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