Basic Study on Vibrational Behavior of Piping Systems Supported by Elasto-Plastic Damper With Gap Support

2014 ◽  
Author(s):  
Keishi Tsujita ◽  
Atsuhiko Shintani ◽  
Tomohiro Ito ◽  
Chihiro Nakagawa
Keyword(s):  
Numerical Simulation ◽  
Analytical Model ◽  
Piping System ◽  
Response Behavior ◽  
Basic Study ◽  
Nonlinear Characteristics ◽  
Vibrational Behavior ◽  
Sinusoidal Input ◽  
Piping Systems

In this study, the vibrational behavior of piping systems supported by elasto-plastic dampers with gap supports was considered. First, an analytical model of L-type piping systems subjected to sinusoidal input was derived, including nonlinear characteristics of the elasto-plastic dampers and gap supports. Next, a numerical simulation was performed to verify the effect of the gap support on the piping system. The effect of the input characteristics on the response behavior of the piping system was investigated.

Basic Study on Dynamic Reliability of Machinery and Piping System Supported by Elasto-Plastic Supports With Gaps

2015 ◽  
Author(s):  
Atsuhiko Shintani ◽  
Keishi Tsujita ◽  
Tomohiro Ito ◽  
Chihiro Nakagawa
Keyword(s):  
White Noise ◽  
Energy Absorption ◽  
Analytical Model ◽  
Piping System ◽  
Basic Study ◽  
Nonlinear Characteristics ◽  
Dynamic Reliability ◽  
Vibrational Behavior ◽  
Stress Energy ◽  
Piping Systems

In this study, the vibrational behavior of piping systems supported by elasto-plastic dampers with gap supports was considered. First, an analytical model of L-type piping systems subjected to white noise was derived, including the nonlinear characteristics of the elasto-plastic dampers and gap supports. After the stress, energy absorption, and other parameters were calculated for many inputs, the dynamic reliability was calculated based on random theory. Optimization of the support locations was investigated. Finally, the effects of a gap support on the dynamic reliability were investigated.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: Computational Approach

2007 ◽  
Author(s):  
Satoshi Tsunoi ◽  
Akira Mikami ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Analytical Model ◽  
Failure Modes ◽  
Experimental Investigations ◽  
Seismic Load ◽  
Piping System ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Seismic Loadings ◽  
Local Wall Thinning

The authors have proposed an analytical model by which they can simulate the dynamic and failure behaviors of piping systems with local wall thinning against seismic loadings. In the previous paper [13], the authors have carried out a series of experimental investigations about dynamic and failure behaviors of the piping system with fully circumferential 50% wall thinning at an elbow or two elbows. In this paper these experiments have been simulated by using the above proposed analytical model and investigated to what extent they can catch the experimental behaviors by simulations.

Basic Study on Optimal Design of System Supporting Structures Subjected to Random Inputs Using the Probabilistic Vibration Theory

2012 ◽  
Author(s):  
Atsuhiko Shintani ◽  
Tadashi Nagami ◽  
Tomohiro Ito ◽  
Chihiro Nakagawa
Keyword(s):  
Optimal Design ◽  
Random Vibration ◽  
Structural Integrity ◽  
Piping System ◽  
Basic Study ◽  
Vibration Theory ◽  
Piping Systems ◽  
Random Vibration Theory ◽  
Noise Input ◽  
Supporting Structures

In this paper, we investigate the optimal design of the piping system supported by elasto-plastic damper subjected to the random input based on the random vibration theory. Using proposed optimal design, the structural integrity of both the piping systems and the elasto-plastic supporting devices are considered and the optimal conditions such as the supporting location, the capacity of the supporting devices are searched. Numerical simulations are performed using a simple piping system model for the white Gaussian noise input based on the random vibration theory.

Application of the Ritz Averaging Method in the Analysis of the Seismic Performance of Piping Systems

1987 ◽  
Vol 109 (3) ◽  
pp. 315-322 ◽  
Author(s):  
M. A. Pickett ◽  
D. J. Cunningham ◽  
S. K. Sinha ◽  
J. Madia
Keyword(s):  
Seismic Performance ◽  
Averaging Method ◽  
Seismic Excitation ◽  
Piping System ◽  
Nonlinear Characteristics ◽  
Normal Limits ◽  
Equivalent Linear ◽  
Piping Systems

The Ritz averaging method is utilized to reduce the nonlinear characteristics of piping system supports (snubbers) to equivalent linear support stiffnesses during seismic excitation. The equivalent snubber support stiffnesses are used in seismic modal analyses of two piping systems. The analyses are performed in order to determine the effect that high snubber lockup velocities have on piping system stresses. The results show that the lockup velocity of snubbers in the systems analyzed can be safely allowed to increase above normal limits without any significant increase in nodal stresses.

Non-Linear Design Verification of Nuclear Power Piping According to ASME III NB/NC

2008 ◽  
Author(s):  
Lingfu Zeng ◽  
Lennart G. Jansson
Keyword(s):  
Nuclear Power ◽  
Design Evaluation ◽  
Piping System ◽  
Design Verification ◽  
Intensive Study ◽  
Non Linear ◽  
Piping Systems ◽  
Design Requirements

A nuclear piping system which is found to be disqualified, i.e. overstressed, in design evaluation in accordance with ASME III, can still be qualified if further non-linear design requirements can be satisfied in refined non-linear analyses in which material plasticity and other non-linear conditions are taken into account. This paper attempts first to categorize the design verification according to ASME III into the linear design and non-linear design verifications. Thereafter, the corresponding design requirements, in particular, those non-linear design requirements, are reviewed and examined in detail. The emphasis is placed on our view on several formulations and design requirements in ASME III when applied to nuclear power piping systems that are currently under intensive study in Sweden.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane, and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

The Influence of Support Hardware and Piping System Seismic Response on Snubber Support Damping

1997 ◽  
Vol 119 (4) ◽  
pp. 451-456 ◽  
Author(s):  
C. Lay ◽  
O. A. Abu-Yasein ◽  
M. A. Pickett ◽  
J. Madia ◽  
S. K. Sinha
Keyword(s):  
Seismic Response ◽  
Fundamental Frequency ◽  
Damping Ratio ◽  
Damping Coefficient ◽  
Piping System ◽  
Nodal Displacement ◽  
Damping Coefficients ◽  
Fundamental Frequencies ◽  
Piping Systems

The damping coefficients and ratios of piping system snubber supports were found to vary logarithmically with pipe support nodal displacement. For piping systems with fundamental frequencies in the range of 0.6 to 6.6 Hz, the support damping ratio for snubber supports was found to increase with increasing fundamental frequency. For 3-kip snubbers, damping coefficient and damping ratio decreased logarithmically with nodal displacement, indicating that the 3-kip snubbers studied behaved essentially as coulomb dampers; while for the 10-kip snubbers studied, damping coefficient and damping ratio increased logarithmically with nodal displacement.

Diffraction Waves About an Advancing Wedge Model in Deep Water

1990 ◽  
Vol 34 (02) ◽  
pp. 105-122
Author(s):  
Hideaki Miyata ◽  
Makoto Kanai ◽  
Noriaki Yoshiyasu ◽  
Yohichi Furuno
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Wedge Angle ◽  
Wave Pattern ◽  
Regular Waves ◽  
Nonlinear Characteristics ◽  
Diffracted Waves ◽  
Nonlinear Features ◽  
Incident Waves

The diffraction of regular waves by advancing wedge models is studied both experimentally and numerically. The nonlinear features of diffracted waves are visualized by wave pattern pictures and the formation is analyzed by the grid-projection method. The experimental observation indicates that the diffracted waves have a number of nonlinear characteristics similar to shock waves due to the interaction of incident waves with the advancing obstacle in the flow-field caused by the advancing motion. Bow waves of both oblique type and normal detached type are observed at remarkably lower Froude numbers than in the case of a ship in steady advance motion. Their occurrence systematically depends on the Froude number and the wedge angle. The numerical simulation of this phenomenon by a finite-difference method shows approximate agreement with the experimental results.

Sensitivity Analyses for a PWR SCC Case Using the Probabilistic Loss-of-Coolant-Accident (Pro-LOCA) Software

2016 ◽  
Author(s):  
Bruce A. Young ◽  
Sang-Min Lee ◽  
Paul M. Scott
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
The United States ◽  
Design Criterion ◽  
Mitigation Strategies ◽  
Sensitivity Analyses ◽  
Base Case ◽  
Piping System ◽  
Loss Of Coolant Accident ◽  
Piping Systems

As a means of demonstrating compliance with the United States Code of Federal Regulations 10CFR50 Appendix A, General Design Criterion 4 (GDC-4) requirement that primary piping systems for nuclear power plants exhibit an extremely low probability of rupture, probabilistic fracture mechanics (PFM) software has become increasingly popular. One of these PFM codes for nuclear piping is Pro-LOCA which has been under development over the last decade. Currently, Pro-LOCA is being enhanced under an international cooperative program entitled PARTRIDGE-II (Probabilistic Analysis as a Regulatory Tool for Risk-Informed Decision GuidancE - Phase II). This paper focuses on the use of a pre-defined set of base-case inputs along with prescribed variation in some of those inputs to determine a comparative set of sensitivity analyses results. The benchmarking case was a circumferential Primary Water Stress Corrosion Crack (PWSCC) in a typical PWR primary piping system. The effects of normal operating loads, temperature, leak detection, inspection frequency and quality, and mitigation strategies on the rupture probability were studied. The results of this study will be compared to the results of other PFM codes using the same base-case and variations in inputs. This study was conducted using Pro-LOCA version 4.1.9.

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