Analysis Bending Solutions of Clamped Rectangular Thick Plate

The bending solutions of rectangular thick plate with all edges clamped and supported were investigated in this study. The basic governing equations used for analysis are based on Mindlin’s higher-order shear deformation plate theory. Using a new function, the three coupled governing equations have been modified to independent partial differential equations that can be solved separately. These equations are coded in terms of deflection of the plate and the mentioned functions. By solving these decoupled equations, the analytic solutions of rectangular thick plate with all edges clamped and supported have been derived. The proposed method eliminates the complicated derivation for calculating coefficients and addresses the solution to problems directly. Moreover, numerical comparison shows the correctness and accuracy of the results

Vibration analysis of a plate with an arbitrarily orientated surface crack

This research presents a vibration analysis for a thin isotropic plate containing an arbitrarily orientated surface crack. The work has been motivated by the well known applicability of various vibrational techniques for structural damage detection in which the detection and localisation of damage to thin plate structures at the earliest stage of development can optimise subsystem performance and assure a safer life, and is intended to be an enhancement to previous work on cracked plates for which the orientation of the crack angle was not included. The novelty of this research activity has been in the assimilation of a significantly enhanced crack model within the analytical model of the plate, in modal space, and taking the form of a specialised Duffing equation. The governing equation of motion of the plate model with enhanced crack modelling is proposed to represent the vibrational response of the plate and is based on classical plate theory into which a developed crack model has been assimilated. The formulation of the angled crack is based on a simplified line-spring model, and the cracked plate is subjected to transverse harmonic excitation with arbitrarily chosen boundary conditions. In addition, the nonlinear behaviour of the cracked plate model is investigated analytically from the amplitude-frequency equation by use of the multiple scales perturbation method. For both cracked square and rectangular plate models, the influence of the boundary conditions, the crack orientation angle, crack length, and location of the point load is demonstrated. It is found that the vibration characteristics and nonlinear characteristics of the cracked plate structure can be greatly affected by the orientation of the crack in the plate. The dynamics and stability of the cracked plate model are also examined numerically using dynamical systems tools for representing the behaviour of this system for a range of parameters. Finally the validity of the developed model is shown through comparison of the results with experimental work and finite element analysis in order to corroborate the effect of crack length and crack orientation angle on the modal parameters, as predicted by the analysis. The results show excellent predictive agreement and it can be seen that the new analytical model could constitute a useful tool for subsequent investigation into the development of damage detection methodologies for generalised plate structures

Vibration Serviceability of Cold-Formed Steel Floor Systems

Excessive vibration in response to human activities has been a significant problem associated with lightweight steel floor systems, especially cold-formed steel (CFS) floors. Methods for accurately predicting these vibrations and evaluating floor systems are not readily available to the design community. The limited amount and complexity of research on the vibration serviceability of lightweight steel floor systems have shown an urgent need for further investigation. The objective of this research is to evaluate how human walking affects the performance of lightweight steel floor systems. Four important aspects that influence floor vibration performance are investigated: rotationally restrained floor joist ends, structural properties of CFS floors, human-structure interactions, and the applicable design guidelines. The investigation was carried out using an analytical approach in which CFS floor systems are modelled by equivalent orthotropic plates, and the equivalent structural properties are determined by using the Rayleigh method. The method of finite integral transform is extended to obtain the exact series solutions of the bending and vibration of orthotropic plates with rotationally restrained edges. The analytical/numerical results are compared to the results obtained in previous methods and experimental investigations. Then, the significant effects of human occupants on the dynamic properties and responses of lightweight steel floors are examined through the proposed damped plate-oscillator model, which determines frequencies and damping ratios through analytical analysis of coupled floor-occupant systems. The predicted results are compared with previous test results. Three loading models--moving force, moving damped-oscillator, and moving and stationary damped-oscillators are subsequently proposed to obtain the dynamic responses of floor systems to human walking. The analytical results from the three models are compared with the previous test results. After that, parametric studies are conducted on the effects of step frequency, damping ratio, human-to-structure mass ratio, and walking path. The foregoing investigations provide a comprehensive understanding of the dynamic performance of lightweight steel floors affected by human walking. Finally, design guidelines are developed for lightweight CFS steel floors in residential constructions. The floors are classified into three categories based on their fundamental frequencies, i.e. low-, mid-, and high-frequency floors. For each category, the corresponding design criterion and method are proposed. It is the author's desire that the contributions made in this thesis research help engineering practitioners better understand the dynamic responses and vibrational characteristics of lightweight CFS floor systems, particularly on human-structure interactions and ultimately lead to the efficient design of lightweight CFS floor systems that resisting the vibration induced by human walking

Elastik ve sönüm mesnetli plakaların titreşimlerinin incelenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu tez çalışmasında, karşılıklı iki kenarından basit mesnetli, diğer iki kenarı boyunca doğrusal yaylar, burulma yayları ve sönüm elemanlarıyla desteklenmiş, ince bir plak modelinin serbest titreşimleri incelenmiştir. Bu plak modelinin hareketine ait diferansiyel denkleminin çözümü için, polinomsal Fourier sinüs serisi kullanılmıştır. Polinomsal Fourier serisi çözüm fonksiyonu, kökleri plak boyutlarıyla orantılı, en düşük dereceden basit bir polinomla, Fourier sinüs serilerinin süper pozisyonundan oluşmaktadır. Çözüm fonksiyonunda polinom kullanılmasının nedeni, plakta oluşabilecek süreksizlik problemlerini önlemek içindir. Çözüm fonksiyonu, sınır şartlarına bağlı olarak elde edilmiştir. Daha sonra, bu çözüm fonksiyonu kullanılarak, elastik destekli ve sınır sönümlü ince plağın diferansiyel denklemi, Galerkin prensibiyle çözülmüş, doğal frekanslar ve frekans parametreleri elde edilmiştir. Çeşitli sönüm değerlerine göre, sönümlü plak modeli için kök değerleri elde edilmiştir. Başlangıç şartları verilerek gerekli katsayılar elde edilmiş ve plağın sönümlü serbest titreşim çözümü bulunmuştur. Mevcut model ve metot literatürdeki sönümsüz durum için yapılmış çalışmalarla birlikte değerlendirilerek, yapılan çalışmanın doğruluğu gösterilmiştir. Sınır şartlarını da içinde barındıran polinomsal Fourier sinüs serisi çözüm fonksiyonunun, elastik ve sönüm destekli ince plakların çözümünde, güvenilir bir şekilde kullanılabileceği gösterilmiştir. Elde edilen sonuçlardan ve grafiklerden, plak kenarlarına yerleştirilen sönüm elemanlarının, plak titreşimlerinin azaltılmasında kullanılabileceği görülmüştür. Plaklarla ilgili sayısız çalışmalar yapılmıştır. Plak titreşim literatüründe, sınır sönümlü plakların serbest titreşimleriyle ilgili çalışmaların yetersiz olduğu görülmüştür. Bu çalışmada elastik ve sönüm mesnetli ince plakların serbest titreşimleri incelenerek literatürdeki eksikliğe katkı yapmak amaçlanmıştır. Tüm hesaplarda, klasik plak teorisi olarak ta isimlendirilen Kirchhoff plak teorisi kullanılmıştır.In this study, free vibrations of a thin plate supported by linear, torsion springs and damping elements along two edges and simple supports on the other edges are examined. Fourier sine series is applied in order to solve the differential equation. Fourier solution function is formed by superposition of Fourier sine series and minimum degree polynomial. In solution function, polynomial is used in order to prevent discontinuity problems. Solution functions are dependent on boundary conditions. Differential equation of plate with elastic and damping is solved by Galerkin principle and frequency and frequency parameters are obtained using the solution function. For damping plate the root values are found with regard to various damping values. The required coefficients are gained by setting initial values and the solution of damping free vibration of the plate is obtained. The existing method is evaluated concerning undamped conditions indicated in literature and the accuracy of the study is determined and presented. It is also introduced that solution functions of Fourier sine series are applied credibly to solutions of thin plates supported by elastic and damping. It is seen from the results that damping elements positioned on the edges of the plate can be also used to reduce plate vibrations. There are numerous studies on plates. It is observed that there are not adequate studies on the free vibration of plates with boundary damping. In this research, free vibration of plates with elastic and damping support is investigated. The classical Kirchhoff’s Plate Theory is applied

Dynamical systems : mechatronics and life sciences

Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version

Multibody dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: Formulations and Numerical Methods, Efficient Methods and Real-Time Applications, Flexible Multibody Dynamics, Contact Dynamics and Constraints, Multiphysics and Coupled Problems, Control and Optimization, Software Development and Computer Technology, Aerospace and Maritime Applications, Biomechanics, Railroad Vehicle Dynamics, Road Vehicle Dynamics, Robotics, Benchmark Problems. The conference is organized by the Department of Mechanical Engineering of the Universitat Politècnica de Catalunya (UPC) in Barcelona. The organizers would like to thank the authors for submitting their contributions, the keynote lecturers for accepting the invitation and for the quality of their talks, the awards and scientific committees for their support to the organization of the conference, and finally the topic organizers for reviewing all extended abstracts and selecting the awards nominees.Postprint (published version