Response of Buried Plastic Pipelines Subject to Lateral Ground Movement

2010 ◽  
Author(s):  
Lalinda Weerasekara ◽  
Dharma Wijewickreme
Keyword(s):  
Material Behavior ◽  
Ground Movement ◽  
Pipe Material ◽  
Pipe Axis ◽  
Force Development ◽  
Strain Behavior ◽  
Ground Deformations ◽  
Nonlinear Stress ◽  
Pipe Segment ◽  
Human Losses

The performance of pipelines in areas prone to ground deformations is a major concern for utility owners since the failures of such pipeline systems could cause property damage and even human losses, in addition to business disruption. An analytical solution to determine the response of plastic pipelines subject to abrupt relative ground movement occurring perpendicular to the pipe axis is presented herein. The method accounts for the combined impacts of tension and bending in a pipe segment. Furthermore, the model considers the nonlinear stress-strain behavior of the pipe material and employs an advanced analytical model to calculate the frictional force development along the pipeline. The results obtained from this analytical approach are validated by comparing with the results obtained from a numerical model using soil-spring analysis and the actual viscoelastic material behavior for the pipe material.

Local Strain Accumulation in Pipeline Girth Welds

2004 ◽  
Author(s):  
William Mohr ◽  
Robin Gordon ◽  
Robert Smith
Keyword(s):  
Local Strain ◽  
Test Methods ◽  
Material Behavior ◽  
Ground Movement ◽  
Performance Criteria ◽  
Weld Strength ◽  
Management Service ◽  
Strain Behavior ◽  
Assessment Guidelines ◽  
Girth Welds

The majority of existing pipeline design codes are stress based and provide limited guidance on the design and assessment of pipelines that may experience high local strains in service. High strains can occur in service due to ground movement, bending over an unsupported span and seismic loading. In such cases pipelines should be designed based on strain capacity. The rigors of strain-based analyses pose a number of challenges, particularly related to pipeline girth welds and general material behavior. This paper presents a summary of an ongoing multi-year project co-funded by the US Minerals Management Service (MMS) and US Dept of Transportation (DOT) to develop design and assessment guidelines for pipelines that may experience high strains in service. Specific topics to be addressed by the project include: • Parent Pipe specifications (Y/T limits, stress-strain behavior, material toughness, etc.); • Welding specifications (joint design, joint geometry, weld strength mismatch, etc.); • Engineering Critical Assessment (ECA) Methods for strain based loading; • Validation test methods to verify pipeline performance (criteria for full-scale testing).

Probabilistic Structural Analysis for Advanced Space Propulsion Systems

1990 ◽  
Vol 112 (2) ◽  
pp. 251-260 ◽  
Author(s):  
T. A. Cruse ◽  
J. F. Unruh ◽  
Y.-T. Wu ◽  
S. V. Harren
Keyword(s):  
Structural Analysis ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Significant Advance ◽  
Space Propulsion ◽  
Stress Strain ◽  
Ongoing Research ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Random Material Properties

This paper reports on recent extensions to ongoing research into probabilistic structural analysis modeling of advanced space propulsion system hardware. The advances concern probabilistic dynamic loading, and probabilistic nonlinear material behavior. In both cases, the reported work represents a significant advance in the state-of-the-art for these topics. Random, or probabilistic loading is normally concerned with the loading described in power spectral density (PSD) terms. The current work describes a method for incorporating random PSD’s along with random material properties, damping, and structural geometry. The probabilistic material response is concerned with the prediction of nonlinear stress-strain behavior for physical processes that can be linked to the original microstructure of the material. Such variables as grain size and orientation, grain boundary strength, etc., are treated as random, initial variables in generating stochastic stress-strain curves. The methodology is demonstrated for a creep simulation.

scholarly journals Probabilistic Structural Analysis for Advanced Space Propulsion Systems

1989 ◽  
Author(s):  
T. A. Cruse ◽  
J. F. Unruh ◽  
Y.-T. Wu ◽  
S. V. Harren
Keyword(s):  
Structural Analysis ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Significant Advance ◽  
Space Propulsion ◽  
Stress Strain ◽  
Ongoing Research ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Random Material Properties

The paper reports on recent extensions to ongoing research into probabilistic structural analysis modeling of advanced space propulsion system hardware. The advances concern probabilistic dynamic loading, and probabilistic nonlinear material behavior. In both cases, the reported work represents a significant advance in the state-of-the-art for these topics. Random, or probabilistic loading is normally concerned with the loading described in power spectral density (PSD) terms. The current work describes a method for incorporating random PSD’s along with random material properties, damping, and structural geometry. The probabilistic material response is concerned with the prediction of nonlinear stress-strain behavior for physical processes that can be linked to the original microstructure of the material. Such variables as grain size and orientation, grain boundary strength, etc. are treated as random, initial variables in generating stochastic stress-strain curves. The methodology is demonstrated for a creep simulation.

Fatigue Investigation of Elastomeric Structures

2010 ◽  
Vol 38 (3) ◽  
pp. 194-212 ◽  
Author(s):  
Bastian Näser ◽  
Michael Kaliske ◽  
Will V. Mars
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Material Behavior ◽  
Period Effect ◽  
Numerical Representation ◽  
Material Force ◽  
Strain Behavior ◽  
Dissipative Effects ◽  
Elastomeric Materials

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.

Cord/Rubber Material Properties

1985 ◽  
Vol 58 (4) ◽  
pp. 830-856 ◽  
Author(s):  
R. J. Cembrola ◽  
T. J. Dudek
Keyword(s):  
Finite Element ◽  
Material Model ◽  
Rubber Composites ◽  
Stress Strain ◽  
Element Analysis ◽  
Rubber Layer ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Interlaminar Shear ◽  
Mechanics Of Composite Materials

Abstract Recent developments in nonlinear finite element methods (FEM) and mechanics of composite materials have made it possible to handle complex tire mechanics problems involving large deformations and moderate strains. The development of an accurate material model for cord/rubber composites is a necessary requirement for the application of these powerful finite element programs to practical problems but involves numerous complexities. Difficulties associated with the application of classical lamination theory to cord/rubber composites were reviewed. The complexity of the material characterization of cord/rubber composites by experimental means was also discussed. This complexity arises from the highly anisotropic properties of twisted cords and the nonlinear stress—strain behavior of the laminates. Micromechanics theories, which have been successfully applied to hard composites (i.e., graphite—epoxy) have been shown to be inadequate in predicting some of the properties of the calendered fabric ply material from the properties of the cord and rubber. Finite element models which include an interply rubber layer to account for the interlaminar shear have been shown to give a better representation of cord/rubber laminate behavior in tension and bending. The application of finite element analysis to more refined models of complex structures like tires, however, requires the development of a more realistic material model which would account for the nonlinear stress—strain properties of cord/rubber composites.

Continuum Description of the Time- and Strain-Dependent Poisson’s Ratio of Ligament Under Finite Deformation

2013 ◽  
Author(s):  
Aaron M. Swedberg ◽  
Shawn P. Reese ◽  
Steve A. Maas ◽  
Benjamin J. Ellis ◽  
Jeffrey A. Weiss
Keyword(s):  
Large Scale ◽  
Mechanical Response ◽  
Tensile Deformation ◽  
Large Strain ◽  
Fiber Direction ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Strain Dependent

Ligament volumetric behavior controls fluid and thus nutrient movement as well as the mechanical response of the tissue to applied loads. The reported Poisson’s ratios for tendon and ligament subjected to tensile deformation loading along the fiber direction are large, ranging from 0.8 ± 0.3 in rat tail tendon fascicles [1] to 2.98 ± 2.59 in bovine flexor tendon [2]. These Poisson’s ratios are indicative of volume loss and thus fluid exudation [3,4]. We have developed micromechanical finite element models that can reproduce both the characteristic nonlinear stress-strain behavior and large, strain-dependent Poisson’s ratios seen in tendons and ligaments [5], but these models are computationally expensive and unfeasible for large scale, whole joint models. The objectives of this research were to develop an anisotropic, continuum based constitutive model for ligaments and tendons that can describe strain-dependent Poisson’s ratios much larger than the isotropic limit of 0.5. Further, we sought to demonstrate the ability of the model to describe experimental data, and to show that the model can be combined with biphasic theory to describe the rate- and time-dependent behavior of ligament and tendon.

Nonlinear Stress-Strain Behavior ofPbZrO3–PbTiO3under Various Temperatures

1994 ◽  
Vol 33 (Part 1, No. 9B) ◽  
pp. 5341-5344 ◽  
Author(s):  
Toshio Tanimoto ◽  
Kohji Yamamoto ◽  
Tohru Morii
Keyword(s):  
Stress Strain ◽  
Strain Behavior ◽  
Nonlinear Stress

scholarly journals 217 Nonlinear stress-strain behavior in CFRP laminates

2002 ◽  
Vol 10.1 (0) ◽  
pp. 461-466
Author(s):  
Shinji Ogihara ◽  
Yusuke Hirakawa ◽  
Nobuo Takeda
Keyword(s):  
Stress Strain ◽  
Cfrp Laminates ◽  
Strain Behavior ◽  
Nonlinear Stress
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