Analyzing pre-stressed steel arch beams

2018 ◽  
Vol 4 (3) ◽  
pp. 95
Author(s):  
Erkan Polat ◽  
Barlas Özden Çağlayan
Keyword(s):  
Full Scale ◽  
Structural Behavior ◽  
Element Analysis ◽  
Load Carrying ◽  
Analysis Computer ◽  
Post Tension ◽  
Pass Through ◽  
Full Scale Tests ◽  
Analysis Computer Program ◽  
Day By Day

Techniques are being developed day-by-day to make it possible to pass through larger openings using smaller beam-column sections. Parallel to this trend, there is another necessity to produce not only smaller but also more economical and architecturally attractive beams. The aim of this study is to explain the structural behavior of steel arch beams reinforced using post-tension cables. Due to the effect of these, the arch beam load carrying capacity increases and a smaller sized optimized section can be obtained with a better architectural view. Moreover, it also allows better mechanical and applicable solutions for buildings. For a better understanding of the behavior of the reinforced beam, a steel beam and a steel arch beam with post-tensioned cables were modeled and analyzed using the SAP2000 finite element analysis computer program and compared with each other. In addition, full-scale specimens were prepared for testing to determine the structural behavior and compare the results with those from the computer modeling, the outcome of which was very promising. The similarity between the results inferred that no extra engineering knowledge and effort are needed to design such beams. The predicted (and proved by the testing) beam bearing capacity was 35% higher than that of the unreinforced beam. With just three full-scale tests completed, it was evident that the ratio (35%) could be increased by adjusting the cable post-tension force on much smaller sized beams.

Fatigue Resistant Threaded and Coupled Connectors for Deepwater Riser Systems: Design and Performance Evaluation by Analysis and Full Scale Tests

2008 ◽  
Author(s):  
Celine Sches ◽  
Emmanuel Desdoit ◽  
Jacky Massaglia
Keyword(s):  
Performance Evaluation ◽  
Fatigue Cracks ◽  
Systems Design ◽  
High Strength Steels ◽  
Full Scale ◽  
Post Treatment ◽  
Mechanism Analysis ◽  
Element Analysis ◽  
And Performance ◽  
Full Scale Tests

Threaded and Coupled (T&C) riser connectors with High Strength Steels have been developed for deepwater top tensioned riser (TTR) applications up to 10,000ft Water Depth. These developments have been ongoing for a decade, and the resulting solutions are now becoming the standard in the industry. Due to the stringent fatigue requirements involved, new design and performance evaluation methods were needed and have been built over time. In this article, we will demonstrate how these methods were implemented into the standard development process of T&C connectors, with a focus on finite element analysis (FEA) techniques. This process includes full scale tests programs on resonant fatigue frames, statistical post treatment of the resulting data, and fatigue cracks expertise for failure mechanism analysis. These elements are a key for the evaluation of T&C connectors’ fatigue performance and for the determination of influencing parameters, leading to the proper design optimization possibilities. The application of these methods will be illustrated with actual examples on T&C connectors’ recent developments. Namely, we will describe FEA methodologies, testing methods and results post-treatment techniques. We will show how the connectors’ performance is eventually derived after such analysis and test data accumulation. The reader will see that innovative and effective fatigue enhancement techniques have resulted, along with premium fatigue compliant sealing devices. The experience and expertise gained, together with a continuous improvement process of our methods have made T&C riser connectors a viable solution to meet emerging needs within deepwater industry, including xHP-HT, SCR and flow lines.

scholarly journals Finite Element Analysis and Full-Scale Testing of Locomotive Crashworthy Components

2013 ◽  
Author(s):  
Patricia Llana ◽  
Richard Stringfellow ◽  
Ronald Mayville
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
New Technologies ◽  
Element Model ◽  
Full Scale ◽  
Element Analysis ◽  
Design Concepts ◽  
Dynamic Finite Element Analysis ◽  
Full Scale Tests ◽  
Force Displacement

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.

Strain Capacity Prediction of Strain-Based Pipelines

2014 ◽  
Author(s):  
Huang Tang ◽  
Doug Fairchild ◽  
Michele Panico ◽  
Justin Crapps ◽  
Wentao Cheng
Keyword(s):  
Damage Mechanics ◽  
Critical Role ◽  
Active Regions ◽  
Full Scale ◽  
Element Analysis ◽  
Strain Capacity ◽  
Fea Model ◽  
Full Scale Tests ◽  
Numerical Program ◽  
Allowable Stress Design

Strain-based design (SBD) is used to complement conventional allowable stress design for pipelines operated in environments with potentially large ground movements such as those found in permafrost and seismically active regions. Reliable and accurate prediction of tensile strain capacity (TSC) plays a critical role in strain-based design. As reported previously over the past 6+ years, a comprehensive experimental and numerical program was undertaken to characterize the TSC of welded pipelines, develop a finite element analysis (FEA) approach and equations capable of predicting TSC, and establish a strain-based engineering critical assessment (SBECA) methodology. The previous FEA model and TSC equations were validated against about 50 full-scale pipe strain capacity tests and are accurate within the validated variable ranges. In the current paper, enhancements of the previous model and equations are described. The enhancements include incorporation of advanced damage mechanics modeling into TSC prediction, development of a new TSC equation, expansion of variable ranges and functionality upgrades. The new model and equation are applicable over larger ranges of material properties and flaw sizes. The new FEA model is also used to establish surface flaw interaction rules for SBD. The new FEA model is validated against more than 40 full-scale non-pressurized and pressurized tests and underpins the development of the new TSC equation. The equation is validated against a total of 93 full-scale tests (FST). In addition to the enhancements, sample applications of the TSC model and equation are presented in the paper, for example, an investigation of the effects on strain capacity of Lüders strain and ductile tearing. Challenges in predicting TSC are also addressed.

Advances in the Railroad Locomotive Crashworthiness

2003 ◽  
Author(s):  
Swamidas Punwani ◽  
Gopal Samavedam ◽  
Steve Kokkins
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Strength ◽  
Full Scale ◽  
Fuel Tank ◽  
Structural Components ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Simulation Results ◽  
Full Scale Tests

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.

scholarly journals Mechanical Properties of Concrete Pipes with Pre-Existing Cracks

2020 ◽  
Vol 10 (4) ◽  
pp. 1545
Author(s):  
Zongyuan Zhang ◽  
Hongyuan Fang ◽  
Bin Li ◽  
Fuming Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bearing Capacity ◽  
Three Dimensional ◽  
Compressive Load ◽  
Full Scale ◽  
Element Analysis ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Full Scale Tests

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.

Research on the Crashworthiness of Neotype Flexible Safety Fence

2012 ◽  
Vol 204-208 ◽  
pp. 1689-1692
Author(s):  
Zheng Bao Lei ◽  
Li Hong Li ◽  
Mu Xi Lei ◽  
Chen Chen Chen
Keyword(s):  
Impact Test ◽  
Lateral Displacement ◽  
Full Scale ◽  
Element Analysis ◽  
Evaluation Standard ◽  
Analysis Computer ◽  
Set Up ◽  
The Impact ◽  
Fence Methods

In order to identify the crashworthiness of neotype flexible safety fence, methods was created by conducting FEA (finite element analysis) computer simulation and full-scale impact test based on the current available evaluation standard. Above all, the model of “vehicle-guardrail” was set up based on virtual proving ground (VPG) pretreatment software, the safety in the impact between vehicle and neotype flexible safety fence were studied from the aspects of the moving locus of vehicle, the acceleration of vehicle and the maximum lateral displacement of guardrail etc. Secondly, full-scale impact test was conducted for the guidance quality of guardrail to the tested vehicle. The test results indicated that the neotype flexible safety fence was inconspicuous to the tested-car, which was basically the same to the simulation results, and the evaluation parameter of guardrail met the acceptance criteria.

Reliability-Based Assessment of Safe Excavation Pressure for Dented Pipelines

2020 ◽  
Author(s):  
Chike Okoloekwe ◽  
Matthew Fowler ◽  
Amandeep Virk ◽  
Nader Yoosef-Ghodsi ◽  
Muntaseer Kainat
Keyword(s):  
Numerical Models ◽  
Mechanical Damage ◽  
Structural Response ◽  
Assessment Method ◽  
Full Scale ◽  
Burst Pressure ◽  
Operating Pressure ◽  
Element Analysis ◽  
Fea Model ◽  
Full Scale Tests

Abstract Dents in a pipe result in alteration of its structural response when subjected to internal pressure. Excavation activities further lead to change in load and boundary conditions of the pipe segment which may exacerbate the stress state within the dented region. Depending on the severity of a dent, excavation under full operating pressure may lead to failure, injuries or fatalities. Although uncommon, an incident has been reported on a gas pipeline where a mechanical damage failed during investigation leading to one death and one injury [10]. While current pipeline regulations require that operators must depressurize a line to ensure safe working conditions during repair activities, there are no detailed provisions available in the codes or standards on how an operator should determine such a safe excavation pressure (SEP). As a result, the safe excavation process of dents has received attention in the industry in recent years. A detailed review of the recent research on dent SEP showed that the current recommendations are primarily dependent on one of two aspects: careful assessment of inline inspection (ILI) data, or a fitness for service (FFS) assessment of the dent feature leveraging numerical models. Enbridge Liquid Pipelines had previously demonstrated a feature specific assessment approach which incorporated both ILI data and finite element analysis (FEA) to determine the SEP. This assessment also accounted for uncertainties associated with material properties and ILI tool measurement. In the previous publication, the authors demonstrated a methodology for assessing the SEP of dents at a conceptual level from both deterministic and reliability-based standpoints. In this paper, a validation study has been performed to compare the results of fracture mechanics based FEA models against ten full scale burst tests available in literature. The study showed good agreement of the burst pressure of dent-crack defects predicted by FEA models with those observed in the full-scale tests. The assessment method is further streamlined by incorporating the API 579 [14] Failure Assessment Diagram (FAD) method on an uncracked FEA model as opposed to explicitly incorporating the crack geometry in the FEA model. The results of FEA in conjunction with FAD are compared with the full-scale tests to ensure accuracy and conservatism of burst pressure prediction. A reliability-based approach is then designed which accounts for the uncertainties associated with the analysis. A case study is presented where the reliability-based SEP assessment method has been implemented and feature specific SEP has been recommended to ensure target reliability during excavation.

A New Rupture Prediction Model for Corroded Pipelines Under Combined Loadings

1998 ◽  
Author(s):  
Wei Wang ◽  
Marina Q. Smith ◽  
Carl H. Popelar ◽  
James A. Maple
Keyword(s):  
Prediction Model ◽  
Thermal Loading ◽  
Axial Loading ◽  
Full Scale ◽  
Element Analysis ◽  
Strain Limit ◽  
Rupture Pressure ◽  
Scale Test ◽  
Full Scale Tests

It is commonly believed that bending and other secondary loading will reduce the rupture pressure of a corroded pipe. This paper shows through theory, full-scale tests and finite element analysis (FEA) that this need not be the case in the field where displacement controlled bending and axial loading are induced by differential settlement and axial constraint. Based on this result, a new strain-based rupture prediction model is developed for buried corroded pipes subjected to internal pressure, lateral bending, thermal loading and residual stress. The selection of an appropriate “bulging factor,” the determination of a biaxial strain limit and the treatment of the heat affected zone (HAZ) are also discussed in the paper. The predicted rupture pressures agree well with the full-scale test results.

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