Mechanical Damage and Fatigue Assessment of Dented Pipelines Using FEA

2014 ◽  
Author(s):  
W. Hanif ◽  
S. Kenny
Keyword(s):  
Mechanical Response ◽  
Damage Zone ◽  
Mechanical Damage ◽  
Numerical Data ◽  
Sensitivity Study ◽  
Third Party ◽  
Analysis Model ◽  
Operational Parameters ◽  
Corrosion Loss ◽  
Wall Loss

Onshore and offshore pipelines may be subjected to mechanical damage during installation and operation due to environmental loads, external forces and third party interference. Pipelines in offshore environment may be prone to mechanical damage from events such as ice gouging, frost heave, and seismic fault movement. For conventional pipelines, the assessment of mechanical damage plays an important role in the development of integrity management programs that may be of greater significance for pipeline systems located in remote harsh environments and that are more prone to anchor drag, seismic loading and ice gouging. This study examines the effect of dents and corrosion loss on pipe mechanical response using continuum finite element methods. ABAQUS/Standard (6.10-1) environment was used to simulate damage events and pipe response. Modelling procedures developed and calibrated against physical and numerical data sets available in public domain were reported previously in Hanif & Kenny 2012, 2013. Once confidence in numerical procedures was established, an analysis model matrix was established to account for a range of influential parameters including pipe/indenter geometry and pressure factor. A nonlinear multivariate regression analysis was conducted to develop strain based empirical tools that characterize the effects of local damage and applied loads on pipeline mechanical response for unconstrained dent conditions. Coupled affect of dent and artificial corrosion loss (in terms of wall thickness reduction in the damage zone) was also analyzed and a sensitivity study was conducted to see the effect of percentage wall loss on pipe response. Finally, operational parameters were varied and resulting stress concentration factors were calculated, that took into account indentations and wall loss, to predict fatigue life of dented pipe segments for both constrained and unconstrained dent conditions.

Assessment of Parameters Influencing Mechanical Response of Constrained and Unconstrained Dents Using Finite Element Modelling

2013 ◽  
Author(s):  
W. Hanif ◽  
S. Kenny
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Mechanical Damage ◽  
Numerical Data ◽  
Performance Criterion ◽  
Metal Loss ◽  
Data Sets ◽  
External Interference ◽  
Seismic Fault ◽  
Girth Welds

Pipelines may experience damage (e.g. dent, gouge) during handling, installation and normal operations due to external interference. Pipelines in offshore environment may be prone to mechanical damage from events such as ice gouging, frost heave, and seismic fault movement. Damage mechanisms can be associated with deformation or metallurgical/metal loss that may include pipe dent, pipe ovality, ice gouging, pipe buckling, corrosion etc. The type and severity of pipe damage may influence operational, repair and intervention strategies. For conventional pipelines, the assessment of mechanical damage plays an important role in the development of integrity management programs that may be of greater significance for pipeline systems located in remote harsh environments due to remote location and logistical constraints. This study examines the effects of plain dents on pipe mechanical response using continuum finite element methods. ABAQUS/Standard (6.10-1) environment was used to simulate damage events and pipe response. Modelling procedures were developed and calibrated against physical and numerical data sets available in public domain. Once confidence in numerical procedures was achieved, an analysis matrix was established to account for a range of influential parameters including Diameter to wall thickness ratio (D/t), indenter diameter to pipe diameter ratio (ID/OD), hoop stress due to internal pressure to yield strength ratio (σh/σy), and kinematic boundary conditions. The results from this study provide a basis to support a broader initiative for developing an engineering tool for the assessment of damage interaction with pipeline girth welds and development of an engineering performance criterion.

scholarly journals Failure Analysis of Apennine Masonry Churches Severely Damaged during the 2016 Central Italy Seismic Sequence

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 58 ◽  
Author(s):  
Francesco Clementi
Keyword(s):  
Case Studies ◽  
Central Italy ◽  
Numerical Data ◽  
Sensitivity Study ◽  
Nonlinear Material ◽  
Seismic Sequence ◽  
Nonlinear Approach ◽  
Nonlinear Static ◽  
Masonry Churches ◽  
Global And Local

This paper presents a detailed study of the damages and collapses suffered by various masonry churches in the aftermath of the seismic sequence of Central Italy in 2016. The damages will first be analyzed and then compared with the numerical data obtained through 3D simulations with eigenfrequency and then nonlinear static analyses (i.e., pushover). The main purposes of this study are: (i) to create an adequately consistent sensitivity study on several definite case studies to obtain an insight into the role played by geometry—which is always unique when referred to churches—and by irregularities; (ii) validate or address the applicability limits of the more widespread nonlinear approach, widely recommended by the Italian Technical Regulations. Pushover analyses are conducted assuming that the masonry behaves as a nonlinear material with different tensile and compressive strengths. The consistent number of case studies investigated will show how conventional static approaches can identify, albeit in a qualitative way, the most critical macro-elements that usually trigger both global and local collapses, underlining once again how the phenomena are affected by the geometry of stones and bricks, the texture of the wall face, and irregularities in the plan and elevation and in addition to hypotheses made on the continuity between orthogonal walls.

scholarly journals Computation of history-dependent mechanical damage of axonal fiber tracts in the brain: towards tracking sub-concussive and occupational damage to the brain

2018 ◽  
Author(s):  
Jesse I. Gerber ◽  
Harsha T. Garimella ◽  
Reuben H. Kraft
Keyword(s):  
Fiber Bundle ◽  
Brain Injuries ◽  
Mechanical Response ◽  
Head Injuries ◽  
Mechanical Damage ◽  
Tissue Level ◽  
Internal Damage ◽  
Damage Models ◽  
Axonal Fiber ◽  
The Brain

ABSTRACTFinite element models are frequently used to simulate traumatic brain injuries. However, current models are unable to capture the progressive damage caused by repeated head trauma. In this work, we propose a method for computing the history-dependent mechanical damage of axonal fiber bundle tracts in the brain. Through the introduction of multiple damage models, we provide the ability to link consecutive head impact simulations, so that potential injury to the brain can be tracked over time. In addition, internal damage variables are used to degrade the mechanical response of each axonal fiber bundle element. As a result, the stiffness of the aggregate tissue decreases as damage evolves. To counteract this degenerative process, we have also introduced a preliminary healing model that reverses the accumulated damage, based on a user-specified healing duration. Using two detailed examples, we demonstrate that damage produces a significant decrease in fiber stress, which ultimately propagates to the tissue level and produces a measurable decrease in overall stiffness. These results suggest that damage modeling has the potential to enhance current brain simulation techniques and lead to new insights, especially in the study of repetitive head injuries.

Multi-Scale Analysis Model of Thermal-Mechanical Damage Effect in High-Power Continuous-Wave Laser Irradiation of CFRP Laminates

2017 ◽  
Vol 44 (6) ◽  
pp. 0602003 ◽  
Author(s):  
赵伟娜 Zhao Weina ◽  
黄亿辉 Huang Yihui ◽  
宋宏伟 Song Hongwei ◽  
黄晨光 Huang Chenguang
Keyword(s):  
Continuous Wave ◽  
Mechanical Damage ◽  
Damage Effect ◽  
Scale Analysis ◽  
Continuous Wave Laser ◽  
Analysis Model ◽  
Cfrp Laminates ◽  
Multi Scale ◽  
Wave Laser ◽  
Multi Scale Analysis

Analyzing the Effectiveness of Prevention Measures for Third-Party Damage to Underground Pipelines Using a Hierarchical Fault Tree Model

2016 ◽  
Author(s):  
Dongliang Lu ◽  
Mark Stephens
Keyword(s):  
Data Collection ◽  
Management Practices ◽  
Fault Tree ◽  
Mechanical Damage ◽  
Third Party ◽  
Weak Links ◽  
Prevention Measures ◽  
Tree Model ◽  
Underground Pipelines ◽  
Damage Prevention

This paper presents a hierarchical fault tree model for analyzing the effectiveness of measures for the prevention of third-party mechanical damage to underground pipelines. The model consists of a high level failure model that provides an overall indication of the effectiveness of a damage prevention program; and lower level fault tree models that detail the effectiveness of individual damage prevention measures. The model developed in this paper is consistent with current damage prevention and data collection practices, and it presents information in a simple and intuitive format that facilitates analysis and interpretation. The hierarchical fault tree approach developed in this paper is shown to be a useful tool for evaluating the effectiveness of various measures to prevent third-party damage and for identifying weak links in current damage management practices. It can also serve to inform the development of new damage prevention techniques and to identify information priorities relevant for future data collection and interpretation efforts aimed at reducing the frequency of third-party damage events.

Basis of the New Criteria in ASME B31.8 for Prioritization and Repair of Mechanical Damage

2002 ◽  
Author(s):  
M. J. Rosenfeld ◽  
John W. Pepper ◽  
Keith Leewis
Keyword(s):  
Natural Gas ◽  
Safety Concern ◽  
Mechanical Damage ◽  
Operating Experience ◽  
Third Party ◽  
Detailed Review ◽  
Natural Gas Pipelines ◽  
Industry Research ◽  
Pipe Section ◽  
New Criteria

Mechanical damage in the form of dents has emerged as a key safety concern for pipelines. In response, ASME B31.8, with assistance from GTI, undertook a detailed review of industry research and operating experience with respect to various forms of mechanical damage. Revised criteria for prioritizing and effectively repairing damage in natural gas pipelines were developed based on the findings. The criteria address plain dents, third-party type damage, dents that affect weldments, dents affected by corrosion, and strain levels associated with deformation of the pipe section. This paper discusses the generalities of the scientific findings and basis for the changes to the Code.

Construction of a Broad-Based Experimental and Computational Test Capability for High Power Wide Bandgap Semiconductor Devices

2007 ◽  
Author(s):  
Jason A. Carter ◽  
Matthew D. Roth ◽  
Michael W. Horgan ◽  
Lisa Shellenberger ◽  
Daniel P. Hoffmann ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
High Electron Mobility Transistors ◽  
Operating Conditions ◽  
High Electron ◽  
Thermal Impedance ◽  
Analysis Model ◽  
Operational Parameters ◽  
Material Interfaces ◽  
Electron Mobility Transistors ◽  
The Impact

In this paper, the authors will discuss the development and implementation of a test stand to assess the impact of temperature on the performance of commercial X-band gallium nitride (GaN) on silicon carbide (SiC) high electron mobility transistors (HEMTs) designed for radio frequency (RF) communications platforms. The devices are tested under a range of operating temperatures and under a range of electrical operating conditions of variable gate and source-drain voltages to assess the impact of temperature on core operational parameters of the device such as channel resistance and transconductance. This test capability includes infrared thermography and transient thermal impedance measurements of the device. In addition to the experimental effort, the initial construction of a finite-volume numerical analysis model of the device will be discussed. The focus of these models will be the accurate assessment of device thermal impedance based on assumed thermal loads and eventually the assessment of accumulated thermal stresses at the material interfaces within the device and package structure.

Structural Optimization Design on the Sunflower Shaped Arch Bridge

2013 ◽  
Vol 427-429 ◽  
pp. 90-93 ◽  
Author(s):  
Wen Qing Wang
Keyword(s):  
Optimization Design ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Orthogonal Experiment ◽  
Design Parameters ◽  
Analysis Model ◽  
Range Analysis ◽  
Element Analysis ◽  
Arch Bridge ◽  
Four Levels

Based on the principle of orthogonal test, the optimization model of sunflower shaped arch bridge scheme was set up. The five key design parameters were selected as the main factors. The four computation index, which reflect mechanical performance, were selected as analytical objects. The 16 orthogonal experiment schemes were arranged with four levels orthogonal table . The curves of the factors to the index were obtained from the mechanical response under dead load and live load through the finite element analysis model. By the range analysis method, the influential levels of the factors to the index were obtained from the result of the test , and the factor optimizatuion level of the factors was determined to further optimize the layout scheme of the sunfloawer shaped arch bridge.

Mechanical response of bridge piles in high-steep slopes and sensitivity study

2015 ◽  
Vol 22 (10) ◽  
pp. 4043-4048 ◽  
Author(s):  
Heng Zhao ◽  
Ping-bao Yin ◽  
Xi-bing Li
Keyword(s):  
Mechanical Response ◽  
Sensitivity Study ◽  
Steep Slopes
Sign in / Sign up

Export Citation Format

Share Document