Journal articles: 'Non-linear dynamic analyses'

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Sun, Huer. "Non-Linear Fracture Mechanics Analyses of Vibrating Screen Arthropleure." Key Engineering Materials 324-325 (November 2006): 767–70. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.767.

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The dynamic properties of the model of vibrating screen are obtained using the software Pro/ MECHANICA. The natural frequencies and mode shapes of the screen are calculated, and the distribution law of dynamic stress is found out. It shows that the structure design of the screen is reasonable. Under the working conditions designed, its dynamic strength is satisfied. This paper provides engineering estimates of non-linear fracture mechanics parameters for vibrating screen arthropleure cracks, subject to alternate stress and Vibrating. Solutions are given in the form of two different approaches.

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Magliulo, Gennaro, Giuseppe Maddaloni, and Edoardo Cosenza. "Comparison between non-linear dynamic analysis performed according to EC8 and elastic and non-linear static analyses." Engineering Structures 29, no. 11 (November 2007): 2893–900. http://dx.doi.org/10.1016/j.engstruct.2007.01.027.

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Soares, D., J. Sladek, and V. Sladek. "Non-linear dynamic analyses by meshless local Petrov-Galerkin formulations." International Journal for Numerical Methods in Engineering 81, no. 13 (October 9, 2009): 1687–99. http://dx.doi.org/10.1002/nme.2756.

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Figini, R., and R. Paolucci. "Integrated foundation-structure seismic assessment through non-linear dynamic analyses." Earthquake Engineering & Structural Dynamics 46, no. 3 (August 3, 2016): 349–67. http://dx.doi.org/10.1002/eqe.2790.

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Reid, S. R., and J. L. Yang. "Non-linear dynamic analysis of cantilever whipping pipes." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 212, no. 3 (August 1, 1998): 133–49. http://dx.doi.org/10.1243/0954408981529367.

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This paper presents the results of numerical dynamic analyses of a number of pipe whip problems based on non-linear shell theory using the DYNA3D (version 6.0) finite element code. The calculations are mainly concerned with the transient deformation of the pipes during the whipping process. The main purpose of the study is to check the efficacy of a recently published theoretical elastic-plastic, hardening-softening (e-p-h-s) model for pipe whip developed by Reid et al. [1, 2]. This model is based upon beam theory but allows for the effects of ovalization of the pipe cross-section on the moment-curvature constitutive behaviour of the pipe. It is shown that the results using DYNA3D are in good agreement with both experimental data and the e-p-h-s model predictions and confirms the accuracy of the latter. While the DYNA3D study is not exhaustive, the localized shell bending deformation of whipping pipes in which ‘kinks’ are formed is reproduced with reasonable accuracy and it has permitted the effect of the strain-rate sensitivity of the yield stress of the pipe material to be examined in a preliminary manner.

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Porcu, Maria Cristina, Juan Carlos Vielma, Francesco Panu, Claudia Aguilar, and Giuseppe Curreli. "Seismic retrofit of existing buildings led by non-linear dynamic analyses." International Journal of Safety and Security Engineering 9, no. 3 (September 9, 2019): 201–12. http://dx.doi.org/10.2495/safe-v9-n3-201-212.

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Greco, Annalisa, and Adolfo Santini. "Comparative study on dynamic analyses of non-classically damped linear systems." Structural Engineering and Mechanics 14, no. 6 (December 25, 2002): 679–98. http://dx.doi.org/10.12989/sem.2002.14.6.679.

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Toki, Kenzo, Fusanori Miura, and Yoshiyuki Oguni. "Dynamic slope stability analyses with a non-linear finite element method." Earthquake Engineering & Structural Dynamics 13, no. 2 (March 1985): 151–71. http://dx.doi.org/10.1002/eqe.4290130203.

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Peña, Fernando, and Miguel Meza. "Seismic Assessment of Bell Towers of Mexican Colonial Churches." Advanced Materials Research 133-134 (October 2010): 585–90. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.585.

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The seismic assessment of bell towers of churches built during the colonial period in Mexico is studied. Two representative typologies of churches of the southwest of Mexico are considered. The results of non-linear static and the non-linear dynamic analyses are compared. The results show that it is not recommended the use of non-linear static analyses; being necessary the use of full non-linear dynamic analyses.

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Capanna, Ilaria, Riccardo Cirella, Angelo Aloisio, Franco Di Fabio, and Massimo Fragiacomo. "Operational Modal Analysis and Non-Linear Dynamic Simulations of a Prototype Low-Rise Masonry Building." Buildings 11, no. 10 (October 13, 2021): 471. http://dx.doi.org/10.3390/buildings11100471.

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This paper focuses on the dynamic behaviour of a low-rise masonry building representing the Italian residential heritage through experimental and numerical analyses. The authors discuss an application of combined Operational Modal Analysis and Finite Element Model updating for indirect estimation of the structural parameters. Two ambient vibration tests were carried out to estimate the structure’s dynamic behaviour in operational conditions. The first experimental setup consisted of accelerometers gathered in a row along the first floor to characterize the local dynamic of the floor. Conversely, the second setup had the accelerometers placed at the building’s corners to characterize the global dynamics. The outcomes of the first setup were used to estimate the mechanical parameters of the floor, while the ones form the second were used to characterize the mechanical parameters of the masonry piers. Therefore, two finite element models were implemented: (i) a single beam with an equivalent section of the floor to grasp the local behaviour of the investigated horizontal structure; (ii) an equivalent frame model of the entire building to characterise the global dynamic behaviour. The model updating process was developed in two phases to seize local and global dynamic responses. The updated numerical model formed the basis for a sensitivity analysis using the modelling parameters. The authors chose to delve into the influence of the floor on the dynamic behaviour of low-rise masonry buildings. With this aim, non-linear dynamic analyses were carried out under different mechanical characteristics of floors, expressing the scatter for ordinary masonry buildings. The displacements’ trends along the height of the building evidenced the notable role of the floor’s stiffness in the non-linear dynamic behaviour of the building. Lastly, the authors derived the fragility curves predicting the seismic performance in failure probability under a highly severe damage state.

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Calderoni, B., and Z. Rinaldi. "Seismic performance evaluation for steel MRF: non linear dynamic and static analyses." Steel and Composite Structures 2, no. 2 (April 25, 2002): 113–28. http://dx.doi.org/10.12989/scs.2002.2.2.113.

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Patra, Pravajyoti, V. Huzur Saran, and SP Harsha. "Non-linear dynamic response analysis of cylindrical roller bearings due to rotational speed." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 233, no. 2 (March 19, 2018): 379–90. http://dx.doi.org/10.1177/1464419318762678.

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The dynamic behaviour of cylindrical roller bearings is presented, in both balanced and unbalanced conditions as a function of speed. The stiffness and damping non-linearities at the contact points (due to Hertzian contact force between rollers and races), radial internal clearance and unbalanced rotor force make the bearing system non-linear. Presently, the differential equations representing the dynamics of the cylindrical roller bearings have been obtained using Lagrange’s equation and solved numerically using modified Newmark-β method. The results of the analyses of various motion behaviours are presented as time–displacement responses, orbit plots, phase portraits, Poincaré maps and Fast Fourier Transform plots. The obtained responses revealed the sensitive behaviour of the system from periodic to quasi-periodic and chaotic with speed variations for both balanced and unbalanced rotor conditions. Also, intermittent chaotic behaviour has been observed. A pattern of the interaction between rotational and variable compliance vibration is observed with speed variations. The frequency pattern analysis (with different techniques used like phase/orbit plots and Poincaré plots) for healthy cylindrical bearing and different rotor conditions under different applied non-linearity consideration is a new attempt to analyse dynamic behaviour of the bearing. This analysis is helpful for online monitoring of fault-free cylindrical roller bearings and for studying the impact of speed on system’s dynamical behaviour.

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Vadeo, S. D., and M. V. Waghmare. "Non-linear Dynamic Analysis of RC Structures Under Earthquake Sequences." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 373–78. http://dx.doi.org/10.38208/acp.v1.524.

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Earthquakes in active seismic regions usually occur in a series of medium to strong intensity ground motions at small intervals of times. A large intensity mainshock (MS) is often followed by a series of aftershocks (AS) or even preceded by smaller foreshocks. This sequence type of mainshock-aftershock (MS-AS) ground motions with varying intensity pose major seismic hazard as there is limited scope of repair and retrofitting between seismic events. Due to continuous and repeated seismic ground motions over a brief period of time, the damages in the structure gets accumulated and structure collapse. This study navigates the behaviour of reinforced concrete structures under such seismic sequences. For this purpose, the nonlinear response of three 12 storey reinforced concrete buildings (regular plan, mass irregularity and diaphragm irregularity) is evaluated. The buildings are subjected to five real seismic sequences from previous earthquakes. Nonlinear dynamic analyses are carried out to study the response of buildings under MS and MS-AS sequences considering: a) material and geometric non linearities and b) irregularities. A single highest aftershock is considered in the present study. The results in this study indicates that MS-AS seismic sequence considering both material and geometric nonlinearities has significant effect on the response of structure. It also showed that seismic sequences significantly alter the response of irregular structure.

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A. Irinyemi, Stephen, Domenico Lombardi, and Syed M. Ahmad. "DYNAMIC RESPONSE AND STABILITY ANALYSES OF AKOSOMBO DAM USING NUMERICAL ANALYSIS." International Journal of Advanced Research 9, no. 10 (October 31, 2021): 639–55. http://dx.doi.org/10.21474/ijar01/13588.

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Dams are very important in Ghanas economic development and environmental improvement. Although Ghana dams are seismically far from the active zone, accurately analysed dams should be evaluated since failure could severely impact the people in the flood environment and the regions economy on a large scale. This paper proposes a numerical procedure for the static, slope stability, and dynamic analysis of the Akosombo embankment dam. Nineteen horizontal acceleration time histories recorded data was used based on Maximum Design Earthquake (MDE), Maximum Credible Earthquake (MCE), Design Basis Earthquake (DBE) and Operating Basis Earthquake (OBE) data. The numerical results estimated showed that the Akosombo embankment dam is likely to experience moderate deformations during the different design earthquakes. The result also indicated that non-linear analysis capable of capturing dominant non-linear mechanisms could be used to assess the stability of embankment dams. The factor of safety (FS) calculated was greater than 1.5 for high reservoir, rapid drawdown condition and low reservoir condition whereas, the FS values were found to be 1.42 for slow drawdown condition.

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Zhao, Mi, Huifang Li, Shengtao Cao, and Xiuli Du. "An explicit time integration algorithm for linear and non-linear finite element analyses of dynamic and wave problems." Engineering Computations 36, no. 1 (December 19, 2018): 161–77. http://dx.doi.org/10.1108/ec-07-2018-0312.

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Purpose The purpose of this paper is to propose a new explicit time integration algorithm for solution to the linear and non-linear finite element equations of structural dynamic and wave propagation problems. Design/methodology/approach The algorithm is completely explicit so that no linear equation system requires solving, if the mass matrix of the finite element equation is diagonal and whether the damping matrix does or not. The algorithm is a single-step method that has the simple starting and is applicable to the analysis with the variable time step size. The algorithm is second-order accurate and conditionally stable. Its numerical stability, dissipation and dispersion are analyzed for the dynamic single-degree-of-freedom equation. The stability of the multi-degrees-of-freedom non-proportional damping system can be evaluated directly by the stability theory on ordinary differential equation. Findings The performance of the proposed algorithm is demonstrated by several numerical examples including the linear single-degree-of-freedom problem, non-linear two-degree-of-freedom problem, wave propagation problem in two-dimensional layer and seismic elastoplastic analysis of high-rise structure. Originality/value A new single-step second-order accurate explicit time integration algorithm is proposed to solve the linear and non-linear dynamic finite element equations. The algorithm has advantages on the numerical stability and accuracy over the existing modified central difference method and Chung-Lee method though the theory and numerical analyses.

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Faggiano, Beatrice, Antonio Formisano, Carmine Castaldo, Luca Canicattì, Raffaele Landolfo, and Federico Massimo Mazzolani. "11.64: Seismic behaviour of steel Chevron bracing systems by non-linear dynamic analyses." ce/papers 1, no. 2-3 (September 2017): 3346–55. http://dx.doi.org/10.1002/cepa.389.

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da Silva, Luis C. M., and Gabriele Milani. "A FE-Based Macro-Element for the Assessment of Masonry Structures: Linear Static, Vibration, and Non-Linear Cyclic Analyses." Applied Sciences 12, no. 3 (January 25, 2022): 1248. http://dx.doi.org/10.3390/app12031248.

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A Finite Element (FE) based macro–element is described for the mechanical response of masonry structures within different ranges of analysis. The macro–element is composed of discrete rigid quadrilateral FE plates whose adjoining interfaces are connected through FE trusses. It allows representing both elasticity and strength orthotropy, full material nonlinearity and damage through a scalar–based model. The possibility of coupling with a so–called FE2 (multi–scale) strategy is also addressed. Validation of the macro–element is conducted within linear static, vibration, and cyclic (nonlinear) problems, in which both static and dynamic ranges are explored. Results are compared with those retrieved from traditional FE continuous models. Advantages are highlighted, as well as its robustness to cope with convergence issues and suitability to be applied within more general and larger–scale scenarios, such as the analysis of anisotropic materials subjected to static and dynamic loading. Formal details are given for its reproducibility by academics and practitioners—eventually within other FE platforms—as the improved running times may be of utmost importance in dynamic problems or highly nonlinear (material) quasi–static analysis.

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Xu, Jun, Yang Li, Jian-feng Mao, Zhi-wu Yu, and Sui Tan. "Dynamic response and reliability analyses of non-linear structures driven by non-stationary non-Gaussian stochastic ground motions." Engineering Structures 268 (October 2022): 114689. http://dx.doi.org/10.1016/j.engstruct.2022.114689.

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Nowakowski, Mirosław, Krzysztof Sibilski, Anna Sibilska-Mroziewicz, and Andrzej Żyluk. "Bifurcation Flight Dynamic Analysis of a Strake-Wing Micro Aerial Vehicle." Applied Sciences 11, no. 4 (February 8, 2021): 1524. http://dx.doi.org/10.3390/app11041524.

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Non-linear phenomena are particularly important in -flight dynamics of micro-class unmanned aerial vehicles. Susceptibility to atmospheric turbulence and high manoeuvrability of such aircraft under critical flight conditions cover non-linear aerodynamics and inertia coupling. The theory of dynamical systems provides methodology for studying systems of non-linear ordinary differential equations. The bifurcation theory forms part of this theory and deals with stability changes leading to qualitatively different system responses. These changes are called bifurcations. There is a number of papers, the authors of which applied the bifurcation theory for analysing aircraft flight dynamics. This article analyses the dynamics of critical micro aerial vehicle flight regimes. The flight dynamics under such conditions is highly non-linear, therefore the bifurcation theory can be applied in the course of the analysis. The application of the theory of dynamical systems enabled predicting the nature of micro aerial vehicle motion instability caused by bifurcations and analysing the post-bifurcation microdrone motion. This article presents the application of bifurcation analysis, complemented with time-domain simulations, to understand the open-loop dynamics of strake-wing micro aerial vehicle model by identifying the attractors of the dynamic system that manages upset behaviour. A number of factors have been identified to cause potential critical states, including non-oscillating spirals and oscillatory spins. The analysis shows that these spirals and spins are connected in a one-parameter space and that due to improper operation of the autopilot on the spiral, it is possible to enter the oscillatory spin.

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Lin-Shi, X., J.-M. Retif, B. Allard, and H. Morel. "Non-linear control design for a boost converter using bond graphs." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 216, no. 1 (February 1, 2002): 1–11. http://dx.doi.org/10.1243/0959651021541363.

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The bond graph technique is applied to model a boost converter in order to derive an averaged model. The obtained averaged model is non-ideal as it takes into account most of the converter non-linearities introduced by power semiconductor devices. An ideal averaged model of the converter can be deduced easily for computing a non-linear control law in a real-time control context. The current-mode control of the boost converter is considered. The zero dynamics are studied by both classical theory and the bond graph approach. A modified version of a conventional nonlinear control law is proposed in order to improve the dynamic behaviour and to reduce the sensitivity to control model errors. The non-ideal averaged model is used firstly for simulation analyses of the proposed control law and then for comparison with experimental results.

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Avila-Haro, Jorge Arturo, Ahmed Saad Elshoura, and Jiří Maca. "Seismic Assessment of Unreinforced Masonry Buildings." Applied Mechanics and Materials 837 (June 2016): 16–21. http://dx.doi.org/10.4028/www.scientific.net/amm.837.16.

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The first case study used in this work is an existing seven-storey unreinforced masonry building (representing a typical residential building located in the district of L ́Example in Barcelona). The accuracy of the non-linear static procedures was evaluated by comparison with non-linear dynamic analyses for seven ground motion records and different levels of seismic intensity. The results obtained from the analyses showed good performance of the static pushover methods on the analysed building. The second case study used in this work is a two-storey unreinforced masonry building which was tested at ELSA in Ispra, Italy. First a modal response spectrum analysis was carried out. Subsequently, non-linear static analysis was performed using two different computer programmes. The results of the present work were compared with experimental results.

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Boubel, Hasnae, Oumnia Elmrabet, Elmehdi Echebba, and Mohamed Rougui. "Seismic analysis of bridges with non-linear soil-structure interaction." Pollack Periodica 16, no. 1 (March 25, 2021): 90–95. http://dx.doi.org/10.1556/606.2020.00236.

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AbstractThis study is concerned to the investigation of the stability of bridges by taking into account the soil structure interaction and their impact on the dynamic behavior of the structures. The bridge studied is localized at PK 318 + 750 at the national level, between the city of Al Hoceima and Kasseta (Morocco). The analyses are carried out with the ANSYS code demonstrated that for conditions of support, the distribution of displacements and the fundamental frequency for each type of soil change according to its mechanical properties. This work also indicates that the proximity of the fundamental frequencies of the soil structure and strongly influences the soil-structure interaction.

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Al-Helwani, Amjad, Mohamad Khir Abdul-wahed, and Mohanad Talal Alfach. "Dynamic behavior assessment of public buildings in Syria using non-linear time-history analysis and ambient noise measurements: a case study." Asian Journal of Civil Engineering 22, no. 4 (January 9, 2021): 637–48. http://dx.doi.org/10.1007/s42107-020-00337-w.

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AbstractThis study evaluates the dynamic behavior and performance of vital reinforced concrete (RC) public building [Ministry of Higher Education (MHE)] designed in compliance with the old Syrian (non-seismic) building code. The real non-linear dynamic behavior of the MHE building has been checked by detailed dynamic numerical analyses (finite elements method—FEM) validated by a series of ambient noise measurements carried out on-site. The modeling approach for the thorough 3D dynamic analyses of the (RC) MHE building has been developed to be able to investigate the actual non-linear dynamic performance of widespread range of RC structures, providing the opportunity to set up a reliable detailed methodology to assess the real dynamic performance of the old vital structures designed according to the old Syrian (non-seismic) building code from the new seismic requirements perspective. The results of the frequency analyses, the nonlinear time history, and the experimental measurements have shown an excellent agreement. The study showed that the modeling approach by the FEM is reliable for predicting the actual dynamic behavior of RC structures, but it is very sensitive to the modeling assumptions. Furthermore, the dynamic performance analyses have revealed unsymmetrical behavior of the east–west wings about the Y-axis which could be attributed to the inefficient seismic rehabilitation executed in 2001.

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Porcu, Maria Cristina, Juan Carlos Vielma Pérez, Gavino Pais, Diego Osorio Bravo, and Juan Carlos Vielma Quintero. "Some Issues in the Seismic Assessment of Shear-Wall Buildings through Code-Compliant Dynamic Analyses." Buildings 12, no. 5 (May 23, 2022): 694. http://dx.doi.org/10.3390/buildings12050694.

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Due to their excellent seismic behavior, shear wall-type concrete buildings are very popular in earthquake-prone countries like Chile. According to current seismic regulations, the performance of such structures can be indifferently assessed through linear or non-linear methods of analysis. Although all the code-compliant approaches supposedly lead to a safe design, linear approaches may be in fact less precise for catching the actual seismic performance of ductile and dissipative structures, which can even result in unconservative design where comparatively stiff buildings like reinforced-concrete shear-wall (RC-SW) buildings are concerned. By referring to a mid-rise multistory RC-SW building built in Chile and designed according to the current seismic Chilean code, the paper investigates the effectiveness of the linear dynamic analyses to predict the seismic performance of such kind of structures. The findings show that the code-compliant linear approaches (Modal Response Spectrum Analysis and Linear Time-History Analysis) may significantly underestimate the displacement demand in RC-SW buildings. This is highlighted by the comparison with the results obtained from the Non-Linear Time-History Analysis, which is expected to give more realistic results. A set of ten spectrum-consistent Chilean earthquakes was considered to carry out the time-history analyses while a distributed-plasticity fiber-based approach was adopted to model the non-linear behavior of the considered building. The paper highlights how the risk of an unsafe design may become higher when reference is made to the Chilean code, the latter considering only the Modal Response Spectrum Analysis (MRSA) without even providing corrective factors to estimate the inelastic displacement demand. The paper checks the effectiveness of some amplifying factors taken from the literature with reference to the case-study shear-wall building, concluding that they are not effective enough. The paper also warns against the danger of local soft-story collapse mechanisms, which are typical of reinforced concrete frames but may also affect RC-SW buildings when weaker structural parts made by column-like walls are present at the ground floor.

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El Haber, Natalie, Bircan Erbas, Keith D. Hill, and John D. Wark. "Relationship between age and measures of balance, strength and gait: linear and non-linear analyses." Clinical Science 114, no. 12 (May 14, 2008): 719–27. http://dx.doi.org/10.1042/cs20070301.

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An age-related decline in balance, gait and lower-extremity muscle strength measures may lead to increased risk of falls and fractures. Previous studies have reported a possible non-linear age-related decline in these measures, but the choice of methodological approach has limited its interpretation. Healthy community-dwelling women (n=212) 21–82 years of age were evaluated for strength [Nicholas MMT (manual muscle tester)], gait [CSA (clinical stride analyser)], activity [HAP (human activity profile)] and static and dynamic balance [CBS (Chattecx balance system), LBT (Lord's balance test) and the ST (step test)]. A GAM (generalized additive model) was developed for each outcome variable to estimate the functional relationship, with age as a continuous variable. Performance was maintained until 45–55 years of age, depending on the outcome measure. Thereafter a decline in performance was evident with increasing age in all measures. Overall, a significant non-linear relationship with age was demonstrated for lower-extremity strength measures (MMT), velocity and double support duration of gait (CSA) and some clinical and laboratory balance tests [ST, LBT (eyes open) and the CBS]. Linear relationships were demonstrated by the LBT with eyes closed and activity measures. Balance, lower-extremity muscle strength and gait may decline non-linearly with age. Our study suggests possible threshold effects between age and balance, muscle strength and gait measures in women. Further research into these threshold effects may have implications for the optimal timing of exercise and other interventions to reduce the risk of falls and fractures.

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Ming, Gao, Dai Guanying, and Yang Jihua. "DYNAMIC STUDIES ON CAISSON-TYFE BREAKWATERS." Coastal Engineering Proceedings 1, no. 21 (January 29, 1988): 183. http://dx.doi.org/10.9753/icce.v21.183.

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In this paper, studies on dynamic characteristics and responses under waves of caisson-type breakwaters by field and model testings as well as dynamic analyses are described. It is found that the gravity-type structure-foundation system can be simplified as a rigid body on a linear or non-linear elastic foundation for evaluating its dynamic characteristics and responses. The dynamic displacements of the caisson are found related to the wave heights, the water depth as well as the foundation soil properties.

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Lakusic, Stjepan. "Seismic vulnerability of an existing strategic RC building using non linear static and dynamic analyses." Journal of the Croatian Association of Civil Engineers 72, no. 07 (August 2020): 617–26. http://dx.doi.org/10.14256/jce.2122.2017.

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da Silveira, Eduardo S. S., Eduardo N. Lages, and Fábio M. G. Ferreira. "DOOLINES : an object-oriented framework for non-linear static and dynamic analyses of offshore lines." Engineering with Computers 28, no. 2 (June 10, 2011): 149–59. http://dx.doi.org/10.1007/s00366-011-0226-x.

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Mouthanna, Ahmed, Sadeq H. Bakhy, and Muhannad Al-Waily. "FREQUENCY OF NON-LINEAR DYNAMIC RESPONSE OF A POROUS FUNCTIONALLY GRADED CYLINDRICAL PANELS." Jurnal Teknologi 84, no. 6 (September 25, 2022): 59–68. http://dx.doi.org/10.11113/jurnalteknologi.v84.18422.

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In this article, a nonlinear dynamical investigation of porose functionally graded cylindrical panels using a proposed analytical model is carried out. The material's properties are considered to be porosity-dependent and graded in the thickness direction, corresponding to a power-law distribution. The classical shell theory, with the geometrical shape of nonlinear in von Karman–Donnell, is employed to get the Lagrange motion equations. By applying the Galerkin procedure, the system of nonlinear dynamic vibration equations is found. The natural frequencies and dynamic amplitude vibrations are obtained by using the fourth-order Runge–Kutta approach. In numerical analyses, the effects of porosity factor, power-law index, porous FGM thickness, frequency–amplitude relation, and excitation force on the dynamic response of thin functionally graded porous cylindrical panels are investigated. Through the obtained results, it is discovered that the porosity coefficients have important effects on the natural frequencies and amplitude of the nonlinear dynamic response of the FG structures. It leads to a reduction in natural frequencies by 5.74 % at 10% pores.

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Buendia-Hernandez, Francisco A., Maria J. Ortiz Bevia, Francisco J. Alvarez-Garcia, and Antonio Ruizde Elvira. "Sensitivity of a Dynamic Model of Air Traffic Emissions to Technological and Environmental Factors." International Journal of Environmental Research and Public Health 19, no. 22 (November 21, 2022): 15406. http://dx.doi.org/10.3390/ijerph192215406.

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In this study, we introduce a sensitivity analysis of modelled CO2 aviation emissions to changes in the model parameters, which is intended as a contribution to the understanding of the atmospheric composition stabilization issue. The two variable dynamic model incorporates the effects of the technological innovations on the emissions rate, the environmental feedback, and a non-linear control term on the passengers rate. The model parameters, estimated from different air traffic sources, are subject to considerable uncertainty. The stability analysis of Monte Carlo simulations revealed that, for certain values of the non-linear term parameter and depending on the type of flight, the passengers number at some equilibrium points exceeded its initial value, while the emissions level was below the initial corresponding one. The results of two global sensitivity analyses indicated that the influence of the non-linear term prevailed on the passengers number rate, followed distantly by the environmental feedback. For the emissions rate, the non-linear term contribution dominated, with the technological term influence placing second.

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Vetter, Daniel, Thomas Hagemann, Andreas Schubert, and Hubert Schwarze. "Approximation of Non-Linear Rotor Dynamic Resonance Behavior of Vertically Aligned Hydro-Units Guided by Tilting-Pad Bearings." Machines 9, no. 12 (December 4, 2021): 334. http://dx.doi.org/10.3390/machines9120334.

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Dynamic analyses of vertical hydro power plant rotors require the consideration of the non-linear bearing characteristics. This study investigates the vibrational behavior of a typical vertical machine using a time integration method that considers non-linear bearing forces. Thereby, the influence of support stiffness and unbalance magnitude is examined. The results show a rising influence of unbalance on resonance speed with increasing support stiffness. Furthermore, simulations reveal that the shaft orbit in the bearing is nearly circular for typical design constellations. This property is applied to derive a novel approximation procedure enabling the examination of non-linear resonance behavior, using linear rotor dynamic theory. The procedure considers the dynamic film pressure for determining the pad position. In addition, it is time-efficient compared to a time integration method, especially at high amplitudes when damping becomes small.

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Shariyat, M. "Non-linear dynamic thermo-mechanical buckling analysis of the imperfect laminated and sandwich cylindrical shells based on a global-local theory inherently suitable for non-linear analyses." International Journal of Non-Linear Mechanics 46, no. 1 (January 2011): 253–71. http://dx.doi.org/10.1016/j.ijnonlinmec.2010.09.006.

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Chincholkar, Satyajit H., Sangmesh V. Malge, and Sanjaykumar L. Patil. "Design and Analysis of a Voltage-Mode Non-Linear Control of a Non-Minimum-Phase Positive Output Elementary Luo Converter." Electronics 11, no. 2 (January 10, 2022): 207. http://dx.doi.org/10.3390/electronics11020207.

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The positive output elementary Luo (POEL) converter is a fourth-order DC–DC converter having highly non-linear dynamic characteristics. In this paper, a new dynamic output voltage feedback controller is proposed to achieve output voltage regulation of the POEL converter. In contrast to the state-of-the-art current-mode controllers for the high-order boost converters, the proposed control strategy uses only the output voltage state variable for feedback purposes. This eliminates the need for the inductor current sensor to reduce the cost and complexity of implementation. The controller design is accompanied by a strong theoretical foundation and detailed stability analyses to obtain some insight into the controlled system. The performance of the proposed controller is then compared with a multi-loop hysteresis-based sliding-mode controller (SMC) to achieve the output voltage-regulation of the same POEL converter. The schemes are compared concerning ease of implementation, in particular, the number of state variables and current sensors required for implementation and the closed-loop dynamic performance. Experimental results illustrating the features of both controllers in the presence of input reference and load changes are presented.

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Abd-Elhamid, Sherif Gamal, Reham Mohamed Galal Ebrahim El-Tahawy, and Mohamed Nour El-Din Fayed. "Dynamic Behavior of Multi-Story Concrete Buildings Based on Non-Linear Pushover & Time History Analyses." Advances in Science, Technology and Engineering Systems Journal 5, no. 2 (2020): 143–53. http://dx.doi.org/10.25046/aj050219.

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Takada, T., and K. Yamaguchi. "Two-step seismic limit state design procedure based on non-linear LRFD and dynamic response analyses." Structural Safety 24, no. 2-4 (April 2002): 397–415. http://dx.doi.org/10.1016/s0167-4730(02)00034-6.

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Mohamed, Osama, and Rania Khattab. "Assessment of Progressive Collapse Resistance of Steel Structures with Moment Resisting Frames." Buildings 9, no. 1 (January 9, 2019): 19. http://dx.doi.org/10.3390/buildings9010019.

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This paper evaluates the practice of using moment connections in the perimeter of the structural system and shear connections within the interior connections of the three-dimensional structural system from the perspective of resistance to progressive collapse. The enhanced resistance to progressive collapse associated with using moment resisting connections at the perimeter as well as internal to the three-dimensional system is assessed. Progressive collapse occurrence and system resistance are determined using the alternate path method which presumes a primary load carrying-member is notionally removed. The paper compares the structural response determined using linear elastic, non-linear elastic and non-linear dynamic analyses. Linear and non-linear static analyses are found to be incapable of capturing the response pursuant to the loss of the primary load carrying member. The analysis procedures used in this study followed (for the most part) the United States Department of Defense Guide for Progressive Collapse Resistant Design of Structures.

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Barbieri, Riccardo, Loren M. Frank, David P. Nguyen, Michael C. Quirk, Victor Solo, Matthew A. Wilson, and Emery N. Brown. "Dynamic Analyses of Information Encoding in Neural Ensembles." Neural Computation 16, no. 2 (February 1, 2004): 277–307. http://dx.doi.org/10.1162/089976604322742038.

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Neural spike train decoding algorithms and techniques to compute Shan-non mutual information are important methods for analyzing how neural systems represent biological signals. Decoding algorithms are also one of several strategies being used to design controls for brain-machine inter-faces. Developing optimal strategies to desig n decoding algorithms and compute mutual information are therefore important problems in com-putational neuroscience. We present a general recursive filter decoding algorithm based on a point process model of individual neuron spiking activity and a linear stochastic state-space model of the biological signal. We derive from the algorithm new instantaneous estimates of the en-tropy, entropy rate, and the mutual information between the signal and the ensemble spiking activity. We assess the accuracy of the algorithm by computing, along with the decoding error, the true coverage probabil-ity of the approximate 0.95 confidence regions for the individual signal estimates. We illustrate the new algorithm by reanalyzing the position and ensemble neural spiking activity of CA1 hippocampal neurons from two rats foraging in an open circular environment. We compare the per-formance of this algorithm with a linear filter constructed by the widely used reverse correlation method. The median decoding error for Animal 1 (2) during 10 minutes of open foraging was 5.9 (5.5) cm, the median entropy was 6.9 (7.0) bits, the median information was 9.4 (9.4) bits, and the true coverage probability for 0.95 confidence regions was 0.67 (0.75) using 34 (32) neurons. These findings improve significantly on our pre-vious results and suggest an integrated approach to dynamically reading neural codes, measuring their properties, and quantifying the accuracy with which encoded information is extracted.

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Francavilla, Antonella B., Massimo Latour, and Gianvittorio Rizzano. "The Design of a Real-Scale Steel Moment-Resisting Frame for Pseudo-Dynamic Earthquake Testing." Open Construction & Building Technology Journal 14, no. 1 (July 30, 2020): 174–84. http://dx.doi.org/10.2174/1874836802014010174.

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Background: Forthe reliable prediction of the non-linear response of structures, severe seismic events have proven to be a challenging task. Although much non-linear analysis software exists, the accuracy of the results depends on the assumptions made in the characterization of the members. Typically, the analytical models are calibrated using experimental observations. With this scope, experimental research remains the most reliable mean for the assessment of the seismic performance of structures, and it is crucial to target the development of new analytical models and design methods. Objective: Quasi-static tests can provide information on the non-linear behaviour of subassemblies, but it is often difficult to relate the imposed force or displacement histories to those that might occur during an earthquake. The pseudo-dynamic method combines an on-line computer simulation with experimental information about the tested structure, providing the application of realistic dynamic response histories. In this paper, the preliminary analysis and the design of a pseudo-dynamic testing facility for the experimental study of a real scale two storeys-two bays steel MRF, with classical and innovative joint details, are shown. Methods: Pushover and Incremental Dynamic Analyses carried out with Seismostruct software estimate the forces and displacements expected at each storey for the selected ground motions. These analyses have been performed by varying the structural detail of the beam-to-column connections. Results / Conclusion: In this paper, the analytical prediction of the performance of two bays-two storeys steel frames equipped with different solutions of beam-to-column joints is focused. Based on the performed analyses, it has been recognized that steel frames with partial strength joints can provide satisfactory performance under severe seismic actions provided that the joints are adequately designed.

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Greco, Annalisa, Ilaria Fiore, Giuseppe Occhipinti, Salvatore Caddemi, Daniele Spina, and Ivo Caliò. "An Equivalent Non-Uniform Beam-Like Model for Dynamic Analysis of Multi-Storey Irregular Buildings." Applied Sciences 10, no. 9 (May 5, 2020): 3212. http://dx.doi.org/10.3390/app10093212.

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Dynamic analyses and seismic assessments of multi-storey buildings at the urban level require large-scale simulations and computational procedures based on simplified but accurate numerical models. For this aim, the present paper proposes an equivalent non-uniform beam-like model, suitable for the dynamic analysis of buildings with an asymmetric plan and non-uniform vertical distribution of mass and stiffness. The equations of motion of this beam-like model, which presents only shear and torsional deformability, were derived through the application of Hamilton’s principle. The linear dynamic behaviour was evaluated by discretizing the continuous non-uniform model according to a Rayleigh–Ritz approach based on a suitable number of modal shapes of the uniform shear-torsional beam. In spite of its simplicity, the model is able to reproduce the dynamic behaviour of low- and mid-rise buildings with a significant reduction of the computational burden with respect to that required by more general models. The efficacy of the proposed approach was tested, by means of comparisons with linear Finite Element Model (FEM) simulations, on three multi-storey buildings characterized by different irregularities. The satisfactory agreement, in terms of natural frequencies, modes of vibration and seismic response, proves the capability of the proposed approach to reproduce the dynamic response of complex spatial multi-storey frames.

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Liu, Ying Li, Chun Miao Li, and Te Liang Yan. "Dynamic Analysis of the Base Isolator Structure." Advanced Materials Research 143-144 (October 2010): 832–36. http://dx.doi.org/10.4028/www.scientific.net/amr.143-144.832.

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Isolators are included in the new earthquake-resistant standard. This article analyses some questions on base-isolators and presents a non-linear dynamic computing-model for the time-history. A corresponding computer program is also compiled. With the program, the earthquake response of a isolated structure including the displacement, acceleration and the shear force of each floor are calculated and compared with those of the same structure without base-isolation. It has been found that base-isolation has important realistic significance in mitigating earthquake disaster effectively and has enormous economic and social benefits. Therefore it is a kind of extremely popularizing and applying new technology.

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Valente, Marco, and Gabriele Milani. "Non-linear dynamic and static analyses on eight historical masonry towers in the North-East of Italy." Engineering Structures 114 (May 2016): 241–70. http://dx.doi.org/10.1016/j.engstruct.2016.02.004.

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Hopkins, Paul M., An Chen, and Mostafa Yossef. "Static and dynamic analyses of insulated concrete sandwich panels using a unified non-linear finite element model." Engineering Structures 132 (February 2017): 249–59. http://dx.doi.org/10.1016/j.engstruct.2016.11.017.

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FUNG, RONG-FONG, and HAN-CHI CHANG. "DYNAMIC AND ENERGETIC ANALYSES OF A STRING/SLIDER NON-LINEAR COUPLING SYSTEM BY VARIABLE GRID FINITE DIFFERENCE." Journal of Sound and Vibration 239, no. 3 (January 2001): 505–14. http://dx.doi.org/10.1006/jsvi.2000.3140.

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Masi, Angelo, and Marco Vona. "Vulnerability assessment of gravity-load designed RC buildings: Evaluation of seismic capacity through non-linear dynamic analyses." Engineering Structures 45 (December 2012): 257–69. http://dx.doi.org/10.1016/j.engstruct.2012.06.043.

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Vaishya, Manish, and Rajendra Singh. "Strategies for Modeling Friction in Gear Dynamics." Journal of Mechanical Design 125, no. 2 (June 1, 2003): 383–93. http://dx.doi.org/10.1115/1.1564063.

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Sliding friction between meshing teeth is one of the primary excitations for noise and vibration in geared systems. Yet, there exist very limited studies on this topic. This paper proposes new modeling strategies for incorporating friction in the dynamic analysis of a gear pair. First, some tribological issues are discussed for estimation of the friction forces under different operating conditions. Second, modeling procedures and results are compared for linear time-invariant, linear time-varying and non-linear time-varying formulations. Criteria such as energy balance, system complexity and desired solution methodology are discussed. Finally, sample results from the various analyses along with their benefits and limitations are examined.

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Ran, Zhi Hong, Jun Tong Qu, Fei He, and Sheng Miao. "Singular Perturbation Method for Solving Non-Linear Vibration of Stay Cable (II) - Engineering Application." Applied Mechanics and Materials 147 (December 2011): 117–21. http://dx.doi.org/10.4028/www.scientific.net/amm.147.117.

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According to vibration characteristic of cable in cable-stayed bridges, the non-linear dynamic model of cables was set up. The vibration differential equation is deduced using the singular perturbation method. The stiffness and coupling boundary conditions of simple and fixed are introduced in the cable force analysis. The useful formulation of measuring techniques for cable force using frequency method is advanced. Results of analyses indicate that the formulation is high in accuracy and convenient in practice. The formulation was used to the cable-stayed construction control of Nanjing Yangtze River No.3 Bridge. The cable force was calculated with test data of vibration, and compared to cable force of design and pressure sensor. The method can be widely used for field of measurement during the construction of cable system structures.

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Paluch, Alicja, and Henryk Spustek. "National Economic Power. Dynamic Model." Security Dimensions 38, no. 38 (December 23, 2021): 22–36. http://dx.doi.org/10.5604/01.3001.0015.6516.

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The national power can be considered in a static and dynamic aspect as well. This applies to all dimensions of the national power, both military and non-military, including the economic one presented in this article. The national power, treated in a static sense as one of the leading features of the state and estimated over a given period, can only be descriptive. On the other hand, it gains a new dimension in a dynamic sense that consists in the possibility of developing the research into a prognostic area. Therefore, this approach to the issue of the national power has been presented here. The research hypothesis is that on the basis of available statistical data it is possible to construct a verifiable dynamic descriptive model of the national economic power, which enables comparative analyses of the group of selected countries. The research took advantage of statistical methods of selecting variables for linear models and methods of system analysis, including multi-criteria, taxonomic method of comparative analysis. Analyses that have been performed allowed to create a dynamic descriptive model of the national power in the economic sphere. The constructed model was positively verified based on the available figures for the selected group of countries. The conducted calculations suggest that it is possible to use this model for further analyses of the national power in the economic sphere.

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Khatiwada, Prashidha, Yiwei Hu, Elisa Lumantarna, and Scott J. Menegon. "Dynamic Modal Analyses of Building Structures Employing Site-Specific Response Spectra Versus Code Response Spectrum Models." CivilEng 4, no. 1 (February 3, 2023): 134–50. http://dx.doi.org/10.3390/civileng4010009.

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This paper is aimed at giving structural designers guidance on how to make use of elastic site-specific response spectra for the dynamic modal analysis of a structure in support of its structural design. The use of response spectra in support of the pushover analysis of an RC building forming part of the non-linear static analysis procedure (that can be used to predict seismic demand without relying on the code-stipulated default R factor) is also presented. Seismic analysis of structures based on the use of site-specific response spectra can help to achieve a more optimised, and cost-effective, structural design compared to the conventional approach employing a response spectrum model stipulated by the code for different site classes. Currently, the methodology is only adopted in major projects in which enough resources are available to engage experts who are skilled in operating the procedure; thus, the use of site-specific response spectra in structural engineering practice is still limited despite the merits of the procedure. Deriving a site-specific response spectrum requires a database of representative ground motion records to be developed. Extra analytical tasks to be undertaken include the processing of bore log data, site response analyses, and selection/scaling of bedrock accelerograms for input into site response analyses. Guidelines for implementing this design methodology are currently lacking. To promote the wide adoption of site-specific seismic design, this article presents the procedure for developing the required site-specific design spectra, as well as guidelines for applying these spectra for seismic design based on analyses of linear, or nonlinear, models of the building. Non-linear analysis can be accomplished by dealing with macroscopic models as illustrated in a case study.

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Germoso, Claudia, Jean Louis Duval, and Francisco Chinesta. "Harmonic-Modal Hybrid Reduced Order Model for the Efficient Integration of Non-Linear Soil Dynamics." Applied Sciences 10, no. 19 (September 27, 2020): 6778. http://dx.doi.org/10.3390/app10196778.

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Nonlinear behavior of soils during a seismic event has a predominant role in current site response analysis. Soil response analysis, and more concretely laboratory data, indicate that the stress-strain relationship of soils is nonlinear and exhibits hysteresis. An equivalent linearization method, in which non-linear characteristics of shear modulus and damping factor of soils are modeled as equivalent linear relations of the shear strain is usually applied, but this assumption, however, may lead to a conservative approach of the seismic design. In this paper, we propose an alternative analysis formulation, able to address forced response simulation of soils exhibiting their characteristic nonlinear behavior. The proposed approach combines ingredients of modal and harmonic analyses enabling efficient time-integration of nonlinear soil behaviors based on the offline construction of a dynamic response parametric solution by using Proper Generalized Decomposition (PGD)-based model order reduction technique.

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Rubanenco, Ionica, and Leonard Domnisoru. "Short Term Prediction of Hydroelastic Dynamic Response in Random Waves for an 1100 TEU Container Ship." Advanced Materials Research 837 (November 2013): 464–70. http://dx.doi.org/10.4028/www.scientific.net/amr.837.464.

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This paper is focused on a short term statistical analysis of the ship dynamic response in random head waves. The waves and the ship responses are considered to be homogenous random processes, being described by a short term Rayleigh first order probability density function. The waves are described in the frequency domain by ITTC power density spectrum function, with time domain formulation by Airy-Faltinsen and Longuet-Higgins models. The numerical analysis are carried out with own program codes package DYN, based on the hydroelasticity theory, with oscillation and vibration components, taking into account the ship speed influence on the dynamic response. The dynamic analysis is based on frequency domain procedures, for linear steady state response, and direct time domain integration procedures, for non-linear and transitory response, resulting power and amplitude density spectrum functions by Fast Fourier Transformation method. The numerical analyses are applied for an optimized 1100 TEU container ship structure, considering six different ship speeds, from 0 to 20 knots, for the full containers loading case. The short term statistical numerical results are pointing out that the ship speed has higher influence on the global vibrations response in compare to the oscillations response, with better accuracy on the non-linear model.

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Journal articles on the topic 'Non-linear dynamic analyses'

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