The Flexural Behavior of Buried Steel and Composite Pipes Pulled Relative to Dense Sand: Experimental and Numerical Investigation

Author(s):  
Mohamed Almahakeri ◽  
Ian D. Moore ◽  
Amir Fam

The flexural behavior of flexible buried pipelines subjected to lateral earth movements is investigated. Two types of pipeline materials, steel and then glass-fiber reinforced polymers (GFRP), are examined. Bending tests are conducted, where two parallel cables attached to a hydraulic actuator load the buried pipe. The study investigated three burial depth-to-diameter ratios (H/D = 3, 5, and 7) representing shallow to deep burial depths commonly used in energy pipeline construction. A three dimensional finite element model for this loading case has also been developed. Data from the numerical simulations are presented and compared to the experimental measurements. This paper provides an overview of the outcomes for this project. For example, while soil resistance was very similar for the two pipe types, the GFRP pipes demonstrated superior flexibility in longitudinal bending compared to the steel pipe. Furthermore, the finite element analyses were able to depict both this similarity in soil resistance, and the significant difference in flexural behavior of the two different pipe materials, the same phenomena observed during testing.

2011 ◽  
Vol 48 (11) ◽  
pp. 1683-1695 ◽  
Author(s):  
Nasser Daiyan ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu

This paper presents results from an experimental and numerical study on the axial–lateral interaction of pipes with dense sand. A series of centrifuge tests were conducted, with a rigid pipeline displaced in the horizontal plane in a cohesionless test bed. The relative pipe–soil interaction included axial, lateral, and oblique loading events. A three-dimensional continuum finite element model was developed using ABAQUS/Standard ( Hibbitt et al. 2005 ) software. The numerical model was calibrated against experimental results. A parametric study was conducted, using the calibrated finite element model to extend the investigations. The ultimate axial and lateral soil loading was found to be dependent on the angle of attack for relative movement between the pipe and soil. Two different failure mechanisms were observed for axial–lateral pipeline–soil interaction. This study confirms and improves on a two-part failure criterion that accounts for axial–lateral coupling during oblique soil loading events on buried pipelines.


2018 ◽  
Vol 21 (12) ◽  
pp. 1777-1791
Author(s):  
Joma HM Omer ◽  
Ahmad BH Kueh ◽  
Poi-Ngian Shek

The flexural behavior of partially welded flush end-plate connections incorporating built-up hybrid beams and columns is analytically and numerically investigated. An experimentally obeying three-dimensional finite element model is first constructed. To circumvent the laborious effort of three-dimensional simulation and experimental work, a new experimentally and numerically complying equation approach is introduced for the construction of a continuous moment–rotation ( M–θ) description. For the proposed equation, two essential terms are required: the rotational stiffness, Sj,ini, obtained by employing the component method and the maximum moment, Mmax, produced using the proposed linearly distributed multi-parameter fitting technique. To demonstrate the applicability of the proposed equation, a variation in the geometric configuration of connections within the practical range is considered. Excellent agreement is noted when comparing all M–θ relationships produced by the proposed equation to those by the finite element method and experiments. In addition, the stress distribution and main deformation modes are numerically obtained, where the ranking of stress criticality is offered for all structural parts. The depth, width, flange, and web thicknesses, as well as the yield stress of the beam, have a major influence on Mmax, as predicted by the proposed equation. Also, bolts have been identified as the most critically stressed component.


1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.


1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.


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