Precise Finite Element Analysis of Full-Scale Straight-Tenon Joints in Ancient Timber Buildings

Author(s):  
Jianyang Xue ◽  
Dejun Song ◽  
Chenwei Wu
Author(s):  
Celal Cakiroglu ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Millan Sen

Pipelines can be subjected to significant amounts of tensile forces due to geotechnical movements like slope instabilities and seismic activities as well as due to frost heave and thaw cycles in arctic regions. The tensile strain capacity εtcrit of pipelines is crucial in the prediction of rupture and loss of containment capability in these load cases. Currently the Oil and Gas Pipeline Systems code CSA Z662-11 0 contains equations for the prediction of εtcrit as a function of geometry and material properties of the pipeline. These equations resulted from extensive experimental and numerical studies carried out by Wang et al [2]–[6] using curved wide plate tests on pipes having grades X65 and higher. Verstraete et al 0 conducted curved wide plate tests at the University of Ghent which also resulted in tensile strain capacity prediction methods and girth weld flaw acceptability criteria. These criteria are included in the European Pipeline Research Group (EPRG) Tier 2 guidelines. Furthermore Verstrate et al 0 introduced a pressure correction factor of 0.5 in order to include the effect of internal pressure in the tensile strain capacity predictions in a conservative way. Further research by Wang et al with full scale pipes having an internal pressure factor of 0.72 also showed that εtcrit decreases in the presence of internal pressure [10]–[15]. In their work, Wang et al presented a clear methodology for the design of full scale experiments and numerical simulations to study the effect of internal pressure on the tensile strain capacity of pipes with girth weld flaws [10]–[15]. However, there has been limited testing to enable a precise understanding of the tensile strain capacity of pipes with grades less than X65 as a function of girth weld flaw sizes and the internal pressure. In this paper the experimental setup for the testing of grade X52 full scale specimens with 12″ diameter and ¼″ wall thickness is demonstrated. In the scope of this research 8 full scale specimens will be tested and the results will be used to formulate the tensile strain capacity of X52 pipes under internal pressure. The specimens are designed for the simultaneous application of displacement controlled tensile loading and the internal pressure. Finite element analysis is applied in the optimization process for the sizes of end plates and connection elements. Also the lengths of the full scale specimens are determined based on the results from finite element analysis. The appropriate lengths are chosen in such a way that between the location of the girth weld flaw and the end plates uniform strain zones could be obtained. The internal pressure in these experiments is ranging between pressure values causing 80% SMYS and 30% SMYS hoop stress. The end plates and connection elements of the specimens are designed in such a way that the tensile displacement load is applied with an eccentricity of 10% of the pipe diameter with the purpose of increasing the magnitude of tensile strains at the girth weld flaw location. The results of two full scale experiments of this research program are presented. The structural response from the experiments is compared to the finite element simulation. The remote strain values of the experiment are found to be higher than the εtcrit values predicted by the equations in 0.


Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 520
Author(s):  
Jordi D’hondt ◽  
Sien Dieltiens ◽  
Marc Juwet

The present article describes the methodology used to design and calibrate a 6-component balance. This balance is utilized in an instrumented bike measuring the forces applied on the handlebars. This instrumentation bike maps all riders induced loads. In the designing process, Finite Element Analysis was used. Calibrating the balance was done using the Least Square Regression Method which allows combining multiple loads during calibration and thus requires less samples. The balance operates with a maximum full scale error of 0.53%.


Author(s):  
Dag Fergestad ◽  
Frank Klæbo ◽  
Jan Muren ◽  
Pål Hylland ◽  
Tom Are Grøv ◽  
...  

This paper discusses the structural challenges associated with high axial temperature gradients and the corresponding internal cross section forces. A representative flexible pipe section designed for high operational temperature has been subject to full scale testing with temperature profiles obtained by external heating and cooling. The test is providing detailed insight in onset and magnitude of relative layer movements and layer forces. As part of the full-scale testing, novel methods for temperature gradient testing of unbonded flexible pipes have been developed, along with layer force- and deflection-measurement techniques. The full-scale test set-up has been subject to numerous temperature cycles of various magnitudes, gradients, absolute temperatures, as well as tension cycling to investigate possible couplings to dynamics. Extensive use of finite element analysis has efficiently supported test planning, instrumentation and execution, as well as enabling increased understanding of the structural interaction within the unbonded flexible pipe cross section. When exploiting the problem by finite element analysis, key inputs will be correct material models for the polymeric layers, and as-built dimensions/thicknesses. Finding the balance between reasonable simplification and model complexity is also a challenge, where access to high quality full-scale tests and dissected pipes coming back from operation provides good support for these decisions. Considering the extensive full scale testing, supported by advanced finite element analysis, it is evident that increased attention will be needed to document reliable operation in the most demanding high temperature flexible pipe applications.


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.


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