Shear and torsion in prestressed hollow core units: finite element analyses of full-scale tests

2007 ◽  
Vol 8 (2) ◽  
pp. 87-100 ◽  
Author(s):  
H. Broo ◽  
K. Lundgren ◽  
B. Engström
Author(s):  
D. DeGeer ◽  
C. Timms ◽  
J. Wolodko ◽  
M. Yarmuch ◽  
R. Preston ◽  
...  

Medgaz is a consortium of leading international energy companies, with the aim of designing, building and operating an Algerian-European gas pipeline via Spain. The offshore section of this pipeline will be 210 km long, traversing the Mediterranean Sea floor at a maximum depth of 2160 metres. The 24-inch diameter, grade X70 line will provide up to 8 billion cubic metres of natural gas per year, with first gas flow expected in 2009. To support the technical issues surrounding such an ultra-deepwater pipelay, a number of full scale local buckling tests and detailed finite element analyses were undertaken at the C-FER facility in Edmonton, Canada. Local buckling conditions of concern included buckling of the pipe section at the pipe-buckle arrestor interface and collapse of the plain pipe under high external pressure. These conditions may arise during various phases of pipeline installation and operation, but the primary focus was to evaluate the local buckling integrity of the pipe during installation using the S-lay method. These conditions were assessed for both as-fabricated pipe and pipe that was heat treated to simulate a pipe coating process. This paper describes the Medgaz pipeline, its current state of development, the installation challenges that necessitated the buckling assessments, and some of the work performed throughout the study, including full scale tests, finite element analyses, and regression analyses. Collapse and critical bending strain predictive equations were developed and are also presented, and are compared to other well known collapse and critical bending strain equations. The results of these assessments have suggested that, for the local buckling conditions presented herein, the S-lay method can be successfully employed for ultra-deep water pipelay. The results demonstrated that the proposed pipe-buckle arrestor connection design will not cause premature buckling as the pipe traverses along the stinger during installation. In addition, potentially high bending strains in the overbend will not significantly influence the collapse strength of the pipe. The regression equations presented in this paper have also been shown to provide an accurate means of predicting pipe local buckling and collapse.


1997 ◽  
Vol 119 (2) ◽  
pp. 81-88 ◽  
Author(s):  
A. P. Assanelli ◽  
Q. Xu ◽  
F. Benedetto ◽  
D. H. Johnson ◽  
E. N. Dvorkin

The objective of the research reported in this paper is to investigate in depth the performance properties of the 5 1/2-in. 14-lb/ft J-55 API 8-round short thread casing connection under different load cases, via experimental tests and finite element analyses. The FEA models are validated by comparing the numerical results with full-scale tests. The validated models are afterwards used to perform parametric studies on the connection behavior.


Author(s):  
Aaron O. Akotuah ◽  
Sabah G. Ali ◽  
Jeffrey Erochko ◽  
Xia Zhang ◽  
George V. Hadjisophocleous

Connection design is critical in timber buildings since the connections tend to have lower strength than the structural members themselves and they tend to fail in a brittle manner. The effect of connection geometry on the fire performance of a hybrid steel-timber shear connection is investigated by full-scale testing. These tests were conducted by exposing the test specimens to the standard time-temperature curve defined by CAN/ULC-S101 (CAN/ULC-S101, 2007). Test results showed that the fire resistance of these connections depends on the load ratio, the type of connection and the relative exposure of the steel plate to fire. Finite element models of the connections under fire were constructed using ABAQUS/CAE and these were validated using the test results. These numerical model results correlate well with test results with ±8.32% variation.


Author(s):  
Malcolm H. Ray

A method of comparing two acceleration time histories to determine whether they describe similar physical events is described. The method can be used to assess the repeatability of full-scale crash tests and it can also be used as a criterion for assessing how well a finite-element analysis of a collision event simulates a corresponding full-scale crash test. The method is used to compare a series of six identical crash tests and then is used to compare several finite-element analyses with full-scale crash test results.


Author(s):  
T. Sriskandarajah ◽  
Venu Rao

Accurate determination of residual ovality is an important parameter for a successful deployment of single pipeline and pipe-in-pipe in deep waters wherein the integrity of empty pipes during installation depends upon the collapse resistance under external hydrostatic pressure. The reel-lay process of installation during which pipeline undergoes multiple strain cycles due to spooling, reeling and straightening has a significant bearing on pipe ovalisation and hence accurate determination residual ovality at the end of straightening process is one of the key inputs. It is industry practice to use numerical finite element analysis techniques to predict residual ovality of pipelines as full scale testing is expensive and time consuming. In view of the importance of residual ovality on the pipeline integrity particularly for deepwater applications, an integrated approach of testing and finite element simulation have been used to identify the correct numerical model that predicts residual ovality accurately. This paper discusses the full scale tests performed which include material testing and bend tests performed to simulate spooling and straightening process and the pipeline deformations recorded using laser measurements at different cycles of bending process. The paper presents a brief summary of numerical finite element analyses performed to validate the test results and the effect of element types and material models used in the finite element analyses on the predictability of residual ovality. The material evolution models and their effect on the predictability of remaining ovality are discussed in the paper. Comparisons are made on the predictive residual ovality for reel lay process on single pipe and pipe-in-pipe. The effect of residual ovality on the pipeline integrity for the lateral buckling limit state under combined bending and external pressure are discussed in the paper.


Author(s):  
Patricia Llana ◽  
Richard Stringfellow ◽  
Ronald Mayville

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. In recognition of the importance of override prevention in train-to-train collisions in which one of the vehicles is a locomotive, and in light of the success of crash energy management technologies in cab car-led passenger trains, the Volpe Center seeks to evaluate the effectiveness of components that could be integrated into the end structure of a locomotive that are specifically designed to mitigate the effects of a collision and, in particular, to prevent override of one of the lead vehicles onto the other. A research program has been conducted to develop, fabricate and test two crashworthy components for the forward end of a locomotive: (1) a deformable anti-climber, and (2) a push-back coupler. Detailed designs for these components were developed, and the performance of each design was evaluated through large deformation dynamic finite element analysis (FEA). Designs for two test articles that could be used to verify the performance of the component designs in full-scale tests were also developed. The two test articles were fabricated and dynamically tested by means of rail car impact in order to verify certain performance characteristics of the two components relative to specific requirements. The tests were successful in demonstrating the effectiveness of the two design concepts. Test results were consistent with finite element model predictions in terms of energy absorption capability, force-displacement behavior and modes of deformation.


Author(s):  
Swamidas Punwani ◽  
Gopal Samavedam ◽  
Steve Kokkins

The paper describes locomotive and fuel tank crashworthiness research being conducted by the Federal Railroad Administration for improved safety of the locomotive crew under collision scenarios. The research involves static and dynamic impact strength evaluations of locomotive structural components. These evaluations which are based on full scale tests and simulations using finite element analysis are described in this paper. Correlations between the test and simulation results are also presented in some cases.


2020 ◽  
Vol 10 (4) ◽  
pp. 1545
Author(s):  
Zongyuan Zhang ◽  
Hongyuan Fang ◽  
Bin Li ◽  
Fuming Wang

Concrete pipes are the most widely used municipal drainage pipes in China. When concrete pipes fall into years of disrepair, numerous problems appear. As one of the most common problems of concrete pipes, cracks impact on the deterioration of mechanical properties of pipes, which cannot be ignored. In the current work, normal concrete pipes and those with pre-existing cracks are tested on a full scale under an external compressive load. The effects of the length, depth, and location of cracks on the bearing capacity and mechanical properties of the concrete pipes are quantitatively analyzed. Based on the full-scale tests, three-dimensional finite element models of normal and cracked concrete pipes are developed, and the measured results are compared with the data of the finite element analysis. It is clear that the test measurements are in good agreement with the simulation results; the bearing capacity of a concrete pipe is inversely proportional to the length and depth of the crack, and the maximum circumferential strain of the pipe occurs at the location of the crack. The strain of the concrete pipe also reveals three stages of elasticity, plasticity, and failure as the external load rises. Finally, when the load series reaches the limit of the failure load of the concrete pipe with pre-existing cracks, the pipe breaks along the crack position.


Author(s):  
Marina Q. Smith ◽  
Daniel P. Nicolella ◽  
Christopher J. Waldhart

The aging of pipeline infrastructures has increased concern for the integrity of pipelines exhibiting non-perforating wall loss and settlement induced bending. While pressure based guidelines exist which allow pipeline operators to define operational margins of safety against rupture (e.g.; ANSI/ASME B31-G and RSTRENG (Battelle, 1989)), reliable procedures for the prediction of wrinkling in degraded pipes subjected to combined loading are virtually non-existent. This paper describes full-scale testing and finite element investigations performed in support of the development of accurate wrinkling prediction procedures for the Alyeska Pipeline Service Company. The procedures are applicable to corroded pipes subjected to combined loading such as longitudinal bending, internal pressure, and axial compression. During the test program, full-scale 48-inch diameter sections of the trans-Alaska pipeline were subjected to internal pressure and loads designed to simulate longitudinal bending from settlement, axial compression from the transport of hot oil, and the axial restraint present in buried pipe. Load magnitudes were designed based on normal and maximum operating conditions. Corrosion in the pipe section is simulated by mechanically reducing the wall thickness of the pipe. The size and depth of the thinned region is defined prior to each test, and attempts to bound the dimensions of depth, axial length, and hoop length for the general corrosion observed in-service. The analytical program utilizes finite element analyses that include the nonlinear anisotropic material behavior of the pipe steel through use of a multilinear kinematic hardening plasticity model. As in the tests, corrosion is simulated in the analyses by a section of reduced wall thickness, and loads and boundary constraints applied to the numerical model exactly emulate those applied in the full-scale tests. Verification of the model accuracy is established through a critical comparison of the simulated pipe structural behavior and the full-scale tests. Results of the comparisons show good correlation with measurements of the pipe curvature, deflections, and moment capacity at wrinkling. The validated analysis procedure is subsequently used to conduct parameter studies, the results of which complete a database of wrinkling conditions for a variety of corrosion sizes and loading conditions.


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