Characterization of Limit State for Seismic Fragility Assessment of T-Joints in Piping System

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Ankit R. Dubey ◽  
Abhinav Gupta ◽  
Sung Gook Cho
Keyword(s):  
Limit State ◽  
Experimental Studies ◽  
State Equation ◽  
Cyclic Behavior ◽  
Piping System ◽  
Damage State ◽  
T Joints ◽  
Performance Function ◽  
A Performance

Abstract Fragility assessment requires characterization of a component or system's performance through a performance function/limit-state equation. The exceedance of limit-state is representative of failure or damage state. For the purposes of evaluating piping fragility, characterizing the behavior of T-joints through an appropriate performance function is critical, as failures in piping are generally localized at the location of T-joints, elbows, and nozzles. Past studies have utilized a monotonic rotation-based performance function. However, the existing criteria does not account for the effect of cyclic behavior. As observed during prior experimental studies, the T-joint behavior under cyclic loading is different from that under monotonic loading, and therefore, it is important to include the effects of cyclic behavior while characterizing a performance function. Moreover, the monotonic rotation-based performance function could not replicate all the leakage locations observed during experimental studies on a full-scale two-story piping system. Therefore, it is important to develop a new limit-state for accurate piping fragility assessment. This paper presents the development of a new limit state which considers the cyclic behavior of a T-joint and quantifies the number of cycles to failure.

Synthesis and characterization of L-threonine ammonium bromide: grown on single crystal with experimental studies on NLO

2021 ◽  
Vol 44 (3) ◽  
Author(s):  
T KALAIARASI ◽  
M SENTHILKUMAR ◽  
S SHANMUGAN ◽  
T JARIN ◽  
V CHITHAMBARAM ◽  
...  
Keyword(s):  
Single Crystal ◽  
Experimental Studies ◽  
Synthesis And Characterization ◽  
Ammonium Bromide

Dynamic Characterization of a Valveless Micropump Considering Entrapped Gas Bubbles

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Songjing Li ◽  
Jixiao Liu ◽  
Dan Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Experimental Studies ◽  
Gas Bubbles ◽  
Chamber Pressure ◽  
Dynamic Characterization ◽  
Valveless Micropump ◽  
Performance Deterioration ◽  
Trapped Gas

Unexpected gas bubbles in microfluidic devices always bring the problems of clogging, performance deterioration, and even device functional failure. For this reason, the aim of this paper is to study the characterization variation of a valveless micropump under different existence conditions of gas bubbles based on a theoretical modeling, numerical simulation, and experiment. In the theoretical model, we couple the vibration of piezoelectric diaphragm, the pressure drop of the nozzle/diffuser and the compressibility of working liquid when gas bubbles are entrapped. To validate the theoretical model, numerical simulation and experimental studies are carried out to investigate the variation of the pump chamber pressure influenced by the gas bubbles. Based on the numerical simulation and the experimental data, the outlet flow rates of the micropump with different size of trapped gas bubbles are calculated and compared, which suggests the influence of the gas bubbles on the dynamic characterization of the valveless micropump.

scholarly journals Properties of the high burnup structure in nuclear light water reactor fuel

2017 ◽  
Vol 105 (11) ◽  
Author(s):  
Thierry Wiss ◽  
Vincenzo V. Rondinella ◽  
Rudy J. M. Konings ◽  
Dragos Staicu ◽  
Dimitrios Papaioannou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Nuclear Fuel ◽  
Experimental Studies ◽  
Fuel Pellet ◽  
Extended Defects ◽  
Safety Margins ◽  
Fission Gas ◽  
High Burnup ◽  
Formed Structure

AbstractThe formation of the high burnup structure (HBS) is possibly the most significant example of the restructuring processes affecting commercial nuclear fuel in-pile. The HBS forms at the relatively cold outer rim of the fuel pellet, where the local burnup is 2–3 times higher than the average pellet burnup, under the combined effects of irradiation and thermo-mechanical conditions determined by the power regime and the fuel rod configuration. The main features of the transformation are the subdivision of the original fuel grains into new sub-micron grains, the relocation of the fission gas into newly formed intergranular pores, and the absence of large concentrations of extended defects in the fuel matrix inside the subdivided grains. The characterization of the newly formed structure and its impact on thermo-physical or mechanical properties is a key requirement to ensure that high burnup fuel operates within the safety margins. This paper presents a synthesis of the main findings from extensive studies performed at JRC-Karlsruhe during the last 25 years to determine properties and behaviour of the HBS. In particular, microstructural features, thermal transport, fission gas behaviour, and thermo-mechanical properties of the HBS will be discussed. The main conclusion of the experimental studies is that the HBS does not compromise the safety of nuclear fuel during normal operations.

Experimental Characterization of FSW T-Joints of Light Alloys

2007 ◽  
Vol 344 ◽  
pp. 751-758 ◽  
Author(s):  
Livan Fratini ◽  
Fabrizio Micari ◽  
Antonio Squillace ◽  
G. Giorleo
Keyword(s):  
Rolling Direction ◽  
Mechanical Analysis ◽  
T Joints ◽  
Light Alloys ◽  
Friction Stir ◽  
Relevant Role ◽  
Numerous Data ◽  
Few Data ◽  
Welding Direction

Welding is playing a growing role in transport industry due to relevant advantages it allows. Friction Stir Welding is considered one of the most promising joining technologies, especially when it is applied to light alloys. Focusing attention on FSW of T-joints, several parameters have to be considered, and due to thermo-mechanical features of process, T joints need a dedicated approach. A set of previously developed experiments has shown that the tilt angle plays a relevant role in the joint strength. Furthermore it should be observed that T-joints are very often utilized in aerospace industries since the produced structures are composed of joined skins and stingers. Numerous data are reported in literature about FSW of butt joints, very few data, to authors’ knowledge, exists on T joints. In this paper a micro structural and mechanical analysis has been developed on FSW T-joints of AA 6082 T6 rolled plates, realized setting welding direction both parallel and perpendicular to rolling direction. The obtained results can be considered as a further acquired knowledge in the comprehension and the design of FSW processes.

A Performance Characterization of Scientific Machine Learning Workflows

2021 ◽  
Author(s):  
Patrycja Krawczuk ◽  
George Papadimitriou ◽  
Ryan Tanaka ◽  
Tu Mai Anh Do ◽  
Srujana Subramanya ◽  
...  
Keyword(s):  
Machine Learning ◽  
Performance Characterization ◽  
A Performance

Studies of the Flame Spraying of Polymers

1996 ◽  
Author(s):  
D.J. Varacalle ◽  
K.W. Couch ◽  
V.S. Budinger
Keyword(s):  
Bond Strength ◽  
Combustion Process ◽  
Experimental Studies ◽  
Polymer Coatings ◽  
Flame Spraying ◽  
Knoop Microhardness ◽  
Resultant Coating ◽  
Strength Characterization ◽  
Thermally Sprayed

Abstract Experimental studies of the subsonic combustion process have been conducted in order to determine the quality and economics of polyester, epoxy, urethane, and hybrid polyester-epoxy coatings. Thermally sprayed polymer coatings are of interest to several industries for anti-corrosion applications, including the infrastructural, chemical, automotive, and aircraft industries. Classical experiments were conducted, from which a substantial range of thermal processing conditions and their effect on the resultant coating were obtained. The coatings were characterized and evaluated by a number of techniques, including Knoop microhardness tests, optical metallography, image analysis, and bond strength. Characterization of the coatings yielded thickness, bond strength, hardness, and porosity.

Experimental study of H∞ control for a flexible plate

2011 ◽  
Vol 18 (11) ◽  
pp. 1631-1649 ◽  
Author(s):  
Zhao Tong ◽  
Chen Long-Xiang ◽  
Cai Guo-Ping
Keyword(s):  
Time Delay ◽  
Integral Transformation ◽  
External Disturbance ◽  
Experimental Studies ◽  
State Equation ◽  
Small Time ◽  
Linear Matrix ◽  
Structural Parameter ◽  
Flexible Plate ◽  
Standard State

This paper presents theoretical and experimental studies of H∞ control for a flexible plate. Firstly, the dynamic equation of the plate with time delay is established with consideration of external disturbance. Then the standard state equation without explicit time delay is deduced by using a particular integral transformation to the time-delay equation. Finally, a H∞ time-delay controller is designed based on the standard state equation using the method of linear matrix inequality. In the controller designed, it contains not only the current step of state feedback but also the linear combination of some former steps of control. In the experiment, piezoelectric patches are used as actuators and sensors. The experiment system is structured based on the DSP TMS320F2812. Single time delay and double time delay are both considered in the experiment. The robustness of H∞ controller against the structural parameter of the plate and time delay is experimentally investigated. Simulation and experimental results indicate that the control system may suffer from instability if time delay is not treated in control design. The time-delay controller presented in this paper can effectively deal with time delay in the system, and is available for small-time delay and large-time delay as well. Furthermore, this delay controller is robust to the variance of structural parameter of the plate and time delay.

Inverse Finite Element Modeling for Characterization of Local Elastic Properties in Image-Guided Failure Assessment of Human Trabecular Bone

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Alexander Zwahlen ◽  
David Christen ◽  
Davide Ruffoni ◽  
Philipp Schneider ◽  
Werner Schmölz ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Bone Structure ◽  
Experimental Studies ◽  
Tissue Level ◽  
Heterogeneous Distribution ◽  
Human Trabecular Bone ◽  
Young’S Moduli ◽  
Failure Assessment ◽  
Experimental Strain

The local interpretation of microfinite element (μFE) simulations plays a pivotal role for studying bone structure–function relationships such as failure processes and bone remodeling. In the past μFE simulations have been successfully validated on the apparent level, however, at the tissue level validations are sparse and less promising. Furthermore, intratrabecular heterogeneity of the material properties has been shown by experimental studies. We proposed an inverse μFE algorithm that iteratively changes the tissue level Young’s moduli such that the μFE simulation matches the experimental strain measurements. The algorithm is setup as a feedback loop where the modulus is iteratively adapted until the simulated strain matches the experimental strain. The experimental strain of human trabecular bone specimens was calculated from time-lapsed images that were gained by combining mechanical testing and synchrotron radiation microcomputed tomography (SRμCT). The inverse μFE algorithm was able to iterate the heterogeneous distribution of moduli such that the resulting μFE simulations matched artificially generated and experimentally measured strains.

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