Reduction of response and first excursion probability for random excitation using nonlinear characteristics

2021 ◽  
pp. 93-100
Author(s):  
S. Aoki
Keyword(s):  
Random Excitation ◽  
Nonlinear Characteristics ◽  
Excursion Probability

Reliability of System With Hysteresis Loop Characteristic Subjected to Earthquake Excitations

2007 ◽  
Author(s):  
Shigeru Aoki
Keyword(s):  
Hysteresis Loop ◽  
Failure Modes ◽  
Estimation Method ◽  
Pressure Vessels ◽  
Nonlinear Characteristics ◽  
Tolerance Level ◽  
Piping Systems ◽  
Time Histories ◽  
Expected Values ◽  
Excursion Probability

Estimation of reliability of system subjected to earthquake excitations is important problem for aseismic design. Reliability of such system should be evaluated in probabilistic manner. First excursion failure is one of the most important failure modes of structures and one of a factor of reliability. Many structures have nonlinear characteristics. Hysteresis loop characteristic caused by plastic deformation is one of the most common nonlinear characteristics observed in pressure vessels and piping systems. In this paper, an estimation method for the first excursion probability of structure with hysteresis loop characteristic is proposed. The first excursion probability is the function of many parameters. First excursion probability is obtained by using artificial time histories. It is shown that when the tolerance level is normalized by the expected values of the maximum response of the structures, the first excursion probability can be shown independent of many parameters.

Reliability of System With Hysteresis Loop Characteristic Subjected to Earthquake Excitations

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Shigeru Aoki
Keyword(s):  
Hysteresis Loop ◽  
Failure Modes ◽  
Estimation Method ◽  
Pressure Vessels ◽  
Nonlinear Characteristics ◽  
Tolerance Level ◽  
Piping Systems ◽  
Time Histories ◽  
Expected Values ◽  
Excursion Probability

The estimation of reliability of system subjected to earthquake excitations is an important problem for aseismic design. The reliability of such system should be evaluated in probabilistic manner. The first excursion failure is one of the most important failure modes of structures and also one factor of reliability. Many structures have nonlinear characteristics. Hysteresis loop characteristic caused by plastic deformation is one of the most common nonlinear characteristics observed in pressure vessels and piping systems. In this paper, an estimation method for the first excursion probability of structure with hysteresis loop characteristic is proposed. The first excursion probability is the function of many parameters, which is obtained by using artificial time histories. It is shown that when the tolerance level is normalized by the expected values of the maximum response of the structures, the first excursion probability can be shown to be independent of many parameters.

Estimation Method for First Excursion Probability of System With Collision Characteristic

2006 ◽  
Author(s):  
Shigeru Aoki
Keyword(s):  
Failure Modes ◽  
Estimation Method ◽  
Pressure Vessels ◽  
Expected Value ◽  
Maximum Response ◽  
Seismic Excitations ◽  
Nonlinear Characteristics ◽  
Tolerance Level ◽  
Piping Systems ◽  
Excursion Probability

Safety of structures subjected to seismic excitations should be evaluated in probabilistic manner. First excursion failure is one of the most important failure modes of structures. Many structures have nonlinear characteristics. Collision characteristic is one of the most common nonlinear characteristics observed in pressure vessels and piping systems. In this paper, an estimation method for the first excursion probability of structure with collision characteristic is proposed. The first excursion probability is the function of many parameters. It is shown that when the tolerance level is normalized by the expected value of the maximum response of the structures, the first excursion probability can be shown to be in dependent of many parameters.

Laser Oscillation in Aggregates of Ultrasmall Si Nanoparticles

2002 ◽  
Vol 728 ◽  
Author(s):  
Munir H. Nayfeh
Keyword(s):  
Stimulated Emission ◽  
Gaussian Beams ◽  
Single Particles ◽  
Nonlinear Characteristics ◽  
Femtosecond Radiation ◽  
Highly Nonlinear ◽  
Line Narrowing ◽  
Si Nanoparticles ◽  
Speckle Patterns ◽  
Spectral Line Narrowing

AbstractWe dispersed electrochemically etched Si into ultrabright ultrasmall nanoparticles, with brightness higher than fluorescein or rhodamine. The emission from single particles is readily detectable. Aggregates or films of the particles exhibit emission with highly nonlinear characteristics. We observe directed blue beams at ∼ 410 nm between faces of aggregates excited by femtosecond radiation at 780 nm; and at ∼ 610 nm from aggregates of red luminescent Si nanoparticles excited by radiation at 550-570 nm from a mercury lamp. Intense directed Gaussian beams, a pumping threshold, spectral line narrowing, and speckle patterns manifest the emission. The results are analyzed in terms of population inversion and stimulated emission in quantum confinement-induced Si-Si dimer phase, found only on ultrasmall Si nanoparticles. This microlasing constitutes an important step towards the realization of a laser on a chip.

Process simulation modeling of phytophagans' influence on the yield of seed fruit crops

2019 ◽  
pp. 138-143
Author(s):  
V. A. Shishkin ◽  
E. P. Rybalkin ◽  
E. B. Balykina
Keyword(s):  
Process Simulation ◽  
Simulation Modeling ◽  
Software Package ◽  
Development Process ◽  
Simulation Models ◽  
Vegetation Period ◽  
Fruit Crops ◽  
Generational Change ◽  
Apple Trees ◽  
Nonlinear Characteristics

Simulation modeling of phytophagans’ influence on the yield of seed fruit crops, in particular apple trees, was carried out. By means of simulation models the importance of phytophagans’ influence at different stages of the vegetation period and the period of fruit ripening was revealed. The software package Matlab was used to build simulation models. As a result, simulation models with nonlinear characteristics were obtained, which maximally reflected the studied processes. The developed models imitate the process of phytophagans’ development. Generation change of pests and all stages of their development are simulated. Their respective numbers are recorded at each stage for all generations. The development process at each stage is modeled by separate subsystems of the simulation model. To simulate the development of one generation of pests, these subsystems are connected by external links. In addition, part of the relationships provides a simulation of generational change. There are a number of input parameters that allow to configure the simulation of the process of changing generations, taking into account the peculiarities of the development of various phytophagans.

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