Determination of Axial Stress in Clad Glass Fibers

The purpose of this paper is to describe the selection process of a rubber-like material model useful for simulation behaviour of an inflatable air cushion under multi-axial stress states. The air cushion is a part of a single segment of a pontoon bridge. The air cushion is constructed of a polyester fabric reinforced membrane such as Hypalon®. From a numerical point of view such a composite type poses a challenge since numerical ill-conditioning can occur due to stiffness differences between rubber and fabric. Due to the analysis of the large deformation dynamic response of the structure, the LS-Dyna code is used. Since LS-Dyna contains more than two-hundred constitutive models the inverse method is used to determine parameters characterizing the material on the base of results of the experimental test.

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Determination of tension strength in the longitudinal and circumferentional direction in glass-polyester composite pipes

Acta periodica technologica ◽

10.2298/apt0940155p ◽

2009 ◽

pp. 155-163 ◽

Cited By ~ 1

Author(s):

Slavisa Putic ◽

Marina Stamenovic ◽

Branislav Bajceta ◽

Dragana Vitkovic

Keyword(s):

Mechanical Test ◽

Glass Fibers ◽

Tension Test ◽

Filament Winding ◽

Test Machine ◽

Process Industries ◽

Polyester Composite ◽

Glass Fiber Reinforcement ◽

Composite Pipes

Polymer composite pipes with glass fiber reinforcement have today a wide usage in the chemical and process industries. The basic subject of this paper is the determination and distribution of stresses and strains in longitudinal and circumferentional directions of glass-polyester pipes under tension test. Also, the tension strengths in both directions are determined out. Tension test was performed on an electro-mechanical test machine on flat samples and rings obtained by cutting of pipes produced by the method 'Filament winding' with glass fibers reinforcement ?55?. Also, the micromechanical analysis on fracture surfaces was done by SEM, which provided the knowledge about models and mechanisms of fracture on applyed loading.

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Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis

Volume 4: Design and Manufacturing ◽

10.1115/imece2009-13289 ◽

2009 ◽

Cited By ~ 1

Author(s):

Michael C. Gibson ◽

Amer Hameed ◽

John G. Hetherington

Keyword(s):

Finite Element ◽

Residual Stresses ◽

Axial Stress ◽

Slope Angle ◽

Subsequent Development ◽

Element Model ◽

Pressure Vessels ◽

Element Analysis ◽

Reverse Yielding

Swaging is one method of autofrettage, a means of pre-stressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A Finite Element model of the swaging process was developed, in ANSYS, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.

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The Effect of Specimen Size on the Determination of Residual Stress in Polymer Pipe Wall

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.627.141 ◽

2014 ◽

Vol 627 ◽

pp. 141-144 ◽

Cited By ~ 1

Author(s):

Jan Poduška ◽

Jaroslav Kučera ◽

Pavel Hutař ◽

Martin Ševčík ◽

J. Křivánek ◽

...

Keyword(s):

Residual Stress ◽

Axial Stress ◽

Three Dimensional ◽

Axial Direction ◽

Polymer Materials ◽

Axial Residual Stress ◽

Axial Dimension ◽

Measured Deformation ◽

Different Dimensions

As a result of the production process, there are axial and tangential residual stresses present in pressure pipes made of polymer materials such as polyethylene or polypropylene. The residual stress magnitude and distribution have a significant influence on the pipe lifetime. In this contribution the results from experiments focused on determining the tangential residual stress distribution in the walls of polypropylene pipes of different dimensions are compared. The experimental method used involves measuring the deformation of ring shaped specimens that were slit in the axial direction. Measured deformation of the ring specimen is a result of the tangential and axial stress superposition. However, the effect of the axial residual stress depends on the specimen axial dimension and tangential residual stress estimated basing on experimental data should be corrected according to axial dimension of the specimen used. The correction suggested in this article is determined based on three-dimensional FEM simulations of the experiment.

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