Stochastic response of a vibro-impact system with variable mass

2019 ◽  
Vol 516 ◽  
pp. 151-160 ◽  
Author(s):  
Chao Li
2021 ◽  
Vol 31 (08) ◽  
pp. 2150139
Author(s):  
Liang Wang ◽  
Bochen Wang ◽  
Jiahui Peng ◽  
Xiaole Yue ◽  
Wei Xu

In this paper, a new impact-to-impact mapping is constructed to investigate the stochastic response of a nonautonomous vibro-impact system. The significant feature lies in the choice of Poincaré section, which consists of impact surface and codimensional time. Firstly, we construct a new impact-to-impact mapping to calculate the one-step transition probability matrix from a given impact to the next. Then, according to the matrix, we can investigate the stochastic responses of a nonautonomous vibro-impact system at the impact instants. The new impact-to-impact mapping is smooth and it effectively overcomes the nondifferentiability caused by the impact. A linear and a nonlinear nonautonomous vibro-impact systems are analyzed to verify the effectiveness of the strategy. The stochastic P-bifurcations induced by the noise intensity and system parameters are studied at the impact instants. Compared with Monte Carlo simulations, the new impact-to-impact strategy is accurate for nonautonomous vibro-impact systems with arbitrary restitution coefficients.


Author(s):  
M. K. Lamvik ◽  
A. V. Crewe

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.


ACS Omega ◽  
2020 ◽  
Vol 5 (45) ◽  
pp. 29209-29221
Author(s):  
Ping Yue ◽  
Hongnan Yang ◽  
Chuanjian He ◽  
G. M. Yu ◽  
James J. Sheng ◽  
...  

2021 ◽  
pp. 107754632110004
Author(s):  
Sanjukta Chakraborty ◽  
Aparna (Dey) Ghosh ◽  
Samit Ray-Chaudhuri

This article presents the design of a tuned mass damper with a conical spring to enable tuning to the natural frequency of the system at multiple values, as may be convenient in case of a system with fluctuations in the mass. The principle and design procedure of the conical spring in the context of a varying mass system are presented. A passive feedback control mechanism based on a simple pulley-mass system is devised to cater to the multi-tuning requirements. A design example of an elevated water tank with fluctuating water content, subjected to ground excitation, is considered to numerically illustrate the efficiency of such a tuned mass damper associated with the conical spring. The conical spring is designed based on the tuning requirements at different mass conditions of the elevated water tank by satisfying the allowable load bearing capacity of the spring. Comparisons are made with the conventional passive tuned mass damper with a linear spring tuned to the full tank condition. Results from time history analysis reveal that the conical spring-tuned mass damper can be successfully designed to remain tuned and thereby achieve significant response reductions under stiffening conditions of the primary structure, whereas the linear spring-tuned mass damper suffers performance degradation because of detuning, whenever there is any fluctuation in the system mass.


Author(s):  
Khangamlung Kamei ◽  
Muhammad A. Khan

AbstractFatigue damage is a concern in the engineering applications particularly for metal structures. The design phase of a structure considers factors that can prevent or delay the fatigue and fracture failures and increase its working life. This paper compiled some of the past efforts to share the modelling challenges. It provides an overview on the existing research complexities in the area of fatigue and fracture modelling. This paper reviews the previous research work under five prominent challenges: assessing fatigue damage accurately under the vibration-based loads, complications in fatigue and fracture life estimation, intricacy in fatigue crack propagation, quantification of cracks and stochastic response of structure under thermal environment. In the conclusion, the authors have suggested new directions of work that still require comprehensive research efforts to bridge the existing gap in the current academic domain due to the highlighted challenges.


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