Anisotropic Fracture Toughness Effects on Failure Modes of Piping

1991 ◽  
Vol 113 (2) ◽  
pp. 154-158 ◽  
Author(s):  
G. M. Wilkowski
Keyword(s):  
Fracture Toughness ◽  
Failure Modes ◽  
Axial Direction ◽  
Combined Loading ◽  
Anisotropic Fracture ◽  
Circumferential Crack ◽  
Growth Plane ◽  
Bending Loads ◽  
Anisotropic Fracture Toughness ◽  
Leak Before Break

This paper summarizes various cases where anisotropic fracture toughness properties caused the failure mode to change during ductile fracture experiments on piping. It is noted that in particular for carbon steel piping, the anisotropy can cause an initial circumferential crack to propagate in a helical or even axial direction, even though there are only applied bending loads. This has implications that under combined loading, such pipes may have lower longitudinal stresses at failure than may be calculated by a leak-before-break analysis that only considers the longitudinal stresses and the toughness in the circumferential crack growth plane.

Crack forbidden area in the anisotropic fracture toughness medium

2018 ◽  
Vol 22 ◽  
pp. 172-175 ◽  
Author(s):  
Yue Gao ◽  
Zhanli Liu ◽  
Tao Wang ◽  
Qinglei Zeng ◽  
Xiang Li ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Anisotropic Fracture ◽  
Anisotropic Fracture Toughness

Characterizing Anisotropic Fracture Toughness of Shale Using Nanoindentation

2021 ◽  
pp. 1-13
Author(s):  
Erica Esatyana ◽  
Mehdi Alipour ◽  
A. Sakhaee-Pour
Keyword(s):  
Fracture Toughness ◽  
Conceptual Model ◽  
Effective Medium Theory ◽  
Fused Silica ◽  
Small Samples ◽  
Medium Theory ◽  
Anisotropic Fracture ◽  
Cube Corner ◽  
Induced Fractures ◽  
Anisotropic Fracture Toughness

Summary Shale, which has pores as small as 10 nm, is economically viable for hydrocarbon recovery when it is fractured. Although the fracture toughness dictates the required energy for the improvement, the existing techniques are not suitable for characterization at scales smaller than 1 cm. Developing practical methods for characterization is crucial because fractures can contribute to an accessible pore volume at different scales. This study proposes a conceptual model to characterize the anisotropic fracture toughness of shale using nanoindentations on a sub-1-cm scale. The conceptual model reveals the complexities of characterizing shales and explains why induced fractures differ from those observed in more-homogeneous media, such as fused silica. Samples from the Wolfcamp Formation were tested using Berkovich and cube-corner tips, and the interpreted fracture toughness values are promising. The conceptual model is the first application of the effective-medium theory for fracture toughness characterization using nanoindentation. In addition, it can quantify fracture toughness variations when using small samples, such as drill cuttings.

XFEM modeling for curved fracture in the anisotropic fracture toughness medium

2018 ◽  
Vol 63 (5) ◽  
pp. 869-883 ◽  
Author(s):  
Yue Gao ◽  
Zhanli Liu ◽  
Tao Wang ◽  
Qinglei Zeng ◽  
Xiang Li ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Anisotropic Fracture ◽  
Anisotropic Fracture Toughness

Anisotropic Fracture Toughness of Bulk GaN

2017 ◽  
Vol 255 (5) ◽  
pp. 1700515 ◽  
Author(s):  
Yutian Cheng ◽  
Duanjun Cai ◽  
Hui Wang ◽  
Jiejun Wu ◽  
Xiangshun Liu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Anisotropic Fracture ◽  
Bulk Gan ◽  
Anisotropic Fracture Toughness

A method to determine site-specific, anisotropic fracture toughness in biological materials

2012 ◽  
Vol 66 (8) ◽  
pp. 515-518 ◽  
Author(s):  
Sabine Bechtle ◽  
Hüseyin Özcoban ◽  
Ezgi D. Yilmaz ◽  
Theo Fett ◽  
Gabriele Rizzi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Biological Materials ◽  
Site Specific ◽  
Anisotropic Fracture ◽  
Anisotropic Fracture Toughness

Theoretical and numerical prediction of crack path in the material with anisotropic fracture toughness

2017 ◽  
Vol 180 ◽  
pp. 330-347 ◽  
Author(s):  
Yue Gao ◽  
Zhanli Liu ◽  
Qinglei Zeng ◽  
Tao Wang ◽  
Zhuo Zhuang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Crack Path ◽  
Numerical Prediction ◽  
Anisotropic Fracture ◽  
Anisotropic Fracture Toughness

scholarly journals Design and analysis of concrete-filled tubular flange girders under combined loading

2021 ◽  
pp. 136943322110015
Author(s):  
Rana Al-Dujele ◽  
Katherine Ann Cashell
Keyword(s):  
Finite Element ◽  
Axial Force ◽  
Failure Modes ◽  
Numerical Study ◽  
Combined Loading ◽  
Torsional Stiffness ◽  
Fe Model ◽  
Combined Effects ◽  
Element Analysis ◽  
Hollow Section

This paper is concerned with the behaviour of concrete-filled tubular flange girders (CFTFGs) under the combination of bending and tensile axial force. CFTFG is a relatively new structural solution comprising a steel beam in which the compression flange plate is replaced with a concrete-filled hollow section to create an efficient and effective load-carrying solution. These members have very high torsional stiffness and lateral torsional buckling strength in comparison with conventional steel I-girders of similar depth, width and steel weight and are there-fore capable of carrying very heavy loads over long spans. Current design codes do not explicitly include guidance for the design of these members, which are asymmetric in nature under the combined effects of tension and bending. The current paper presents a numerical study into the behaviour of CFTFGs under the combined effects of positive bending and axial tension. The study includes different loading combinations and the associated failure modes are identified and discussed. To facilitate this study, a finite element (FE) model is developed using the ABAQUS software which is capable of capturing both the geometric and material nonlinearities of the behaviour. Based on the results of finite element analysis, the moment–axial force interaction relationship is presented and a simplified equation is proposed for the design of CFTFGs under combined bending and tensile axial force.

Elastic-plastic bending of the pipeline under combined loading

2021 ◽  
pp. 372-377
Author(s):  
Виктор Миронович Варшицкий ◽  
Евгений Павлович Студёнов ◽  
Олег Александрович Козырев ◽  
Эльдар Намикович Фигаров
Keyword(s):  
Internal Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Axial Direction ◽  
Longitudinal Force ◽  
Combined Loading ◽  
Dimensional Problem ◽  
Elastic Plastic ◽  
Pipeline Section ◽  
Thin Walled Pipe

Рассмотрена задача упругопластического деформирования тонкостенной трубы при комбинированном нагружении изгибающим моментом, осевой силой и внутренним давлением. Решение задачи осуществлено по разработанной методике с помощью математического пакета Matcad численным методом, основанным на деформационной теории пластичности и безмоментной теории оболочек. Для упрощения решения предложено сведение двумерной задачи к одномерной задаче о деформировании балки, материал которой имеет различные диаграммы деформирования при сжатии и растяжении в осевом направлении. Проведено сравнение с результатами численного решения двумерной задачи методом конечных элементов в упругопластической постановке. Результаты расчета по инженерной методике совпадают с точным решением с точностью, необходимой для практического применения. Полученные результаты упругопластического решения для изгибающего момента в сечении трубопровода при комбинированном нагружении позволяют уточнить известное критериальное соотношение прочности сечения трубопровода с кольцевым дефектом в сторону снижения перебраковки. Применение разработанной методики позволяет ранжировать участки трубопровода с непроектным изгибом по степени близости к предельному состоянию при комбинированном нагружении изгибающим моментом, продольным усилием и внутренним давлением. The problem of elastic plastic deformation of a thin-walled pipe under co-binned loading by bending moment, axial force and internal pressure is considered. The problem is solved by the developed method using the Matcad mathematical package by a numerical method based on the deformation theory of plasticity and the momentless theory of shells. To simplify the solution of the problem, it is proposed to reduce a twodimensional problem to a one-dimensional problem about beam deformation, the material of which has different deformation diagrams under compression and tension in the axial direction. Comparison with the results of numerical solution of the two-dimensional problem with the finite element method in the elastic plastic formulation is carried out. The obtained results of the elastic-plastic solution for the bending moment in the pipeline section under combined loading make it possible to clarify criterion ratio of the strength of the pipeline section with an annular defect in the direction of reducing the rejection. Application of the developed approach allows to rank pipeline sections with non-design bending in the steppe close to the limit state under combined loading of the pipeline with bending moment, longitudinal force and internal pressure.

Sign in / Sign up

Export Citation Format

Share Document