Faststofmekanik

The book presents formulations and examples of three-dimensional non-axisymmetric stability in viscoelastic anisotropic cylindrical shells. The most critical stability loss modes are determined by minimizing the critical loads and critical times with respect to the number of half-waves in radial as well as transverse directions.Currently, there is no literature available on three-dimensional local buckling analysis (or localized warpage) that considers non-axisymmetric stability loss in viscoelastic cylindrical shells. The contents of this book provide the formulation for such a stability loss analysis through the framework of the three-dimensional linearized theory of stability. Additionally, as this book addresses the problem by modeling the material as a viscoelastic fibrous composite, it can be applied to carry out buckling analysis in both elastic and viscoelastic cases.Guide to modelling composite viscoelastic shell elements for buckling analysisProvides a framework for defining the failure criterion for viscoelastic materialsCourse material for teaching shell buckling and viscoelastic composites

Nonlinear Structures & Systems, Volume 1: Proceedings of the 41st IMAC, A Conference and Exposition on Structural Dynamics, 2023, the first volume of ten from the Conference brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Nonlinear Dynamics, including papers on:Experimental Nonlinear DynamicsJointed Structures: Identification, Mechanics, DynamicsNonlinear DampingNonlinear Modeling and SimulationNonlinear Reduced-Order ModelingNonlinearity and System Identification

This volume gathers select proceedings of the 10th International Conference on Wave Mechanics and Vibrations (WMVC), held in Lisbon, Portugal, on July 4-6, 2022. It covers recent developments and cutting-edge methods in wave mechanics and vibrations applied to a wide range of engineering problems. It presents analytical and computational studies in structural mechanics, seismology and earthquake engineering, mechanical engineering, aeronautics, robotics and nuclear engineering among others. The volume will be of interest for students, researchers, and professionals interested in the wide-ranging applications of wave mechanics and vibrations. 

This textbook has been written for the engineering students. This textbook covers the essentials of solid mechanics with reference to basic load-bearing members¿straight bars, thin-walled cylindrical and spherical pressure vessels, circular shafts, beams undergoing simple bending, and columns. It concisely elucidates the corresponding fundamental assumptions, important equations, and their range of validity without formal derivations. Subsequently, this textbook contains several carefully selected examples to illustrate sequence of steps in the analysis of forces, stresses and displacements, or stability. It further deals with combined loading, stress and strain transformations, energy methods, and failure analysis using commonly employed criteria. This textbook is a handy, yet complete, resource for graduate and postgraduate engineering students. It will also be a ready reference for a practicing engineers or graduate students preparing for an interview or a competitive examination.

This monograph examines the stability of various coupled systems with local Kelvin-Voigt damping. The development of this area is thoroughly reviewed along with the authors' contributions. New results are featured on the fundamental properties of solutions of linear transmission evolution PDEs involving Kelvin-Voigt damping, with special emphasis on the asymptotic behavior of these solutions. The vibrations of transmission problems are highlighted as well, making this a valuable resource for those studying this active area of research. The book begins with a brief description of the abstract theory of linear evolution equations with a particular focus on semigroup theory. Different types of stability are also introduced along with their connection to resolvent estimates. After this foundation is established, different models are presented for uni-dimensional and multi-dimensional linear transmission evolution partial differential equations with Kelvin-Voigt damping. Stabilization of Kelvin-Voigt Damped Systems will be a useful reference for researchers in mechanics, particularly those interested in the study of control theory of PDEs.

Um bei der Fertigung von Faserverbundkunststoffen Zeit, Energie und Kosten sparen zu können, werden möglichst viele Informationen über die Vorgänge während des Fertigungsprozesses benötigt. Die Integration von Foliensensoren in die hergestellten Bauteile ist eine von mehreren Möglichkeiten, diese Informationen zu erhalten. Foliensensoren bestehen aus einer thermoplastischen Folie, auf der metallische Elektroden strukturiert sind. Ihre Integration in das Bauteil bringt unterschiedliche Vor- und Nachteile mit sich. Einerseits sind bauteilintegrierte Sensoren flexibler einsetzbar als werkzeugintegrierte Sensoren und ermöglichen eine feinere räumliche Auflösung der Aushärtevorgänge. Andererseits werden sie bei der Fertigung zum Produktbestandteil. Sie sollten deswegen einfach und kostengünstig sein, sowie die Lasttragfähigkeit nicht beeinträchtigen. Aus mechanischer Sicht bringen Foliensensoren vor allem ein Delaminationsrisiko mit sich. Die Wahl des thermoplastischen Substratmaterials macht dabei den entscheidenden Einflussfaktor aus. Während Sensoren auf Basis des häufig verwendeten Materials Polyimid ein erhebliches Delaminationsrisiko mit sich bringen, ist der Einfluss von Polyetherimid weit weniger schädlich oder verbessert sogar einzelne Festigkeitskennwerte. Neben dem Substratmaterial wirken sich auch die metallischen Sensorstrukturen auf die Belastbarkeit aus. Zur Gestaltung minimalinvasiver Sensoren sollte ein möglichst geringer Metallisierungsgrad angestrebt werden. Das verbreitetste Design für Foliensensoren zur Aushärteüberwachung sind sogenannte Interdigitalelektroden, die eine elektrische Kapazität bilden, deren Impedanz von der direkten Umgebung beeinflusst wird. In variothermen Fertigungsprozessen besteht eine Herausforderung darin, den Einfluss der Temperatur von dem des Aushärtegrades zu trennen. Die an integrierten Sensoren gemessenen Impedanzinformationen müssen dazu eine Verarbeitung durchlaufen, in deren Verlauf die Frequenzabhängigkeit und die Einflüsse von Temperatur und Sensorgeometrie aus den Daten entfernt werden. Für eine variotherme Aushärteüberwachung ist daher die Verwendung eines zusätzlichen Temperatursensors unverzichtbar. Die Sensordaten bieten darüber hinaus Potential für die Ermittlung des Faservolumengehalts oder zur Detektion von Harzfehlanmischungen.

Das Verständnis der Physik von Festkörpern hat im letzten Jahrhundert enorme Fortschritte gemacht und unser tägliches Leben in vielerlei Hinsicht revolutioniert. Diese Entwicklung geht weiter, und es besteht kaum ein Zweifel daran, dass die moderne Festkörperphysik notwendig ist, um einige der Herausforderungen zu bewältigen, denen wir uns heute gegenübersehen. In seiner 6., überarbeiteten Auflage deckt das Werk ein breites Spektrum physikalischer Phänomene ab, die in Festkörpern auftreten, und erörtert grundlegende Konzepte zu deren Beschreibung. Das Material ist so ausgewählt, dass alle relevanten aktuellen Teilgebiete einbezogen werden und zusammen einen umfassenden Überblick bieten. Eine Besonderheit dieses Lehrbuches ist, dass die Physik ungeordneter Festkörper, die üblicherweise meist nur sehr kurz oder gar nicht dargestellt wird, konsequent in die Behandlung des Stoffes einfließt und die Physik der idealen Kristalle ergänzt. Ungeordnete Festkörper sind in unserem täglichen Leben allgegenwärtig und spielen in zahlreichen technischen Anwendungen eine wichtige Rolle. Das Lehrbuch richtet sich an Studierende, die Festkörperphysik auf einführendem und fortgeschrittenem Vorlesungsniveau studieren wollen.

This book presents selected, peer-reviewed contributions from the 9th International Conference on Experimental Vibration Analysis for Civil Engineering Structures (EVACES 2021), organized by the University of Tokyo and Saitama University from September 17-20, 2021 on the Hongo campus of the University of Tokyo, and hosted in an online format. The event brought together engineers, scientists, researchers, and practitioners, providing a forum for discussing and disseminating the latest developments and achievements in all major aspects of dynamic testing for civil engineering structures, including instrumentation, sources of excitation, data analysis, system identification, monitoring and condition assessment, in-situ and laboratory experiments, codes and standards, and vibration mitigation. The topics of EVACES 2021 included but were not limited to: damage identification and structural health monitoring; testing, sensing and modeling; vibration isolation and control; system and model identification; coupled dynamical systems (including human-structure, vehicle-structure, and soil-structure interaction); and application of advanced techniques involving the Internet of Things, robot, UAV, big data and artificial intelligence.

This book provides an overview of direct methods, such as limit and shakedown analysis, which are intended for avoiding cumbersome step-by-step calculations to determine the limit states of mechanical structures under monotone, cyclic or variable actions with unknown loading history. The book comprises several contributions that demonstrate how tremendous advances in numerical methods, especially in optimization, have contributed to the success of direct methods and their applicability to practical engineering problems in structural mechanics and mechanics of materials. The contents reflect the outcomes of the workshop ¿Direct Methods for Limit State of Materials and Structures,¿ held in Cosenza, Italy in June 2022.

This book offers a current state of the art in analysis and modeling of creep phenomena with applications to the structural mechanics. It presents the some presentations from the IUTAM-Symposium series "Creep in Structures", which held in Magdeburg (Germany) in September 2023, and it discusses many advances and new results in the field. These are for example: interlinks of mechanics with materials science in multi-scale analysis of deformation and damage mechanisms over a wide range of stresses and temperature; development and analysis of new alloys for (ultra)high-temperature applications; formulation and calibration of advanced constitutive models of inelastic behavior under transient loading and temperature conditions; development of efficient procedures and machine learning techniques for identification of material parameters in advanced constitutive laws; introduction of gradient-enhanced and non-local theories to account for damage and fracture processes; and applicationof new experimental methods, such as digital image correlation, for the analysis of inelastic deformation under multi-axial stress state.

Special Topics in Structural Dynamics & Experimental Techniques, Volume 5: Proceedings of the 40th MAC, A Conference and Exposition on Structural Dynamics, 2022, the fifth volume of nine from the Conference brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on:Analytical MethodsEmerging Technologies for Structural DynamicsEngineering ExtremesExperimental TechniquesFinite Element Techniques

Topics in Modal Analysis & Testing, Volume 8: Proceedings of the 40th IMAC, A Conference and Exposition on Structural Dynamics, 2022, the eighth volume of nine from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Modal Analysis, including papers on:Operational Modal & Modal Analysis ApplicationsExperimental TechniquesModal Analysis, Measurements & Parameter EstimationModal Vectors & ModelingBasics of Modal AnalysisAdditive Manufacturing & Modal Testing of Printed Parts

This book presents select, recent developments in nonlinear and complex systems reported at the 1st Online Conference on Nonlinear Dynamics and Complexity, held on November 23-25, 2020. It provides an exchange recent developments, discoveries, and progresses in Nonlinear Dynamics and Complexity. The collection presents fundamental and frontier theories and techniques for modern science and technology, stimulates more research interest for exploration of nonlinear science and complexity; and passes along new knowledge and insight to the next generation of engineers and technologists in a range of fields. 

Many materials can be modeled either as discrete systems or as continua, depending on the scale. At intermediate scales it is necessary to understand the transition from discrete to continuous models and variational methods have proved successful in this task, especially for systems, both stochastic and deterministic, that depend on lattice energies. This is the first systematic and unified presentation of research in the area over the last 20 years. The authors begin with a very general and flexible compactness and representation result, complemented by a thorough exploration of problems for ferromagnetic energies with applications ranging from optimal design to quasicrystals and percolation. This leads to a treatment of frustrated systems, and infinite-dimensional systems with diffuse interfaces. Each topic is presented with examples, proofs and applications. Written by leading experts, it is suitable as a graduate course text as well as being an invaluable reference for researchers.

This book offers an interdisciplinary theoretical approach based on non-equilibrium statistical thermodynamics and control theory for mathematically modeling shock-induced out-of-equilibrium processes in condensed matter. The book comprises two parts. The first half of the book establishes the theoretical approach, reviewing fundamentals of non-equilibrium statistical thermodynamics and control theory of adaptive systems. The latter half applies the presented approach to a problem on shock-induced plane wave propagation in condensed matter. The result successfully reproduces the observed feature of waveform propagation in experiments, which conventional continuous mechanics cannot access. Further, the consequent stress-strain relationships derived with relaxation and inertia effect in elastic-plastic transition determines material properties in transient regimes.

This book describes the design experience of automatic machines and the theoretical background for controlling them. Unlike the existing literature, it includes design concepts and their relationship with the dynamic behavior of automated devices, and links the dynamic response of the machine elements with the actuators that constitute an automatic machine. As such, it demonstrates that it is vital to properly model any automatic machine as a single system and find the final response to have a good design and control scheme. The introduction describes the background for designing automatic machines, their uniqueness in machine design, and the need to understand dynamic behavior. The following chapters provide the background for modeling multibody systems, examples of typical automatic machines, and the basis for determining the dynamic response of the most common actuators (motor, pneumatic, and hydraulic pistons and valves). The fourth chapter describes the dynamic response of the most common sensors utilized in automatic machines, while the fifth chapter includes the dynamic models of the machine elements that connect the actuators with the end effects (specific tools for each particular application). The final chapters contain examples of dynamic models for different automatic machines, including all the elements that affect the final response, and describe the simulation techniques (and their application to the examples) and the application of the transfer function for estimating the transient response of automatic machines.

Balancing of rotors is an indispensable process for the quality management, involving many stages from design to commissioning. With every further development of rotors - with new concepts, materials and machining methods - the demands on balancing technology change. In the search for the optimum solution to these complex tasks, no patent remedies will help, but only a sound knowledge of the theoretical background of balancing, its practical implementation and the performance of the various balancing systems.This book is intended to support systematic familiarisation with the subject and ongoing training - in practice as well as in theory.The focus of current balancing standards is on deviations that occur during balancing - intentionally generated, or accidentally created. They must be properly analysed and taken into account in order to determine the permissible indications for residual unbalance. In addition, the acceptance criteria were specified so that the balancing objective - the targeted balancing quality - can be reliably achieved.When balancing rotors with shaft-elastic behaviour, work is often still carried out according to outdated patterns. For this reason, the new modal approach was further elaborated - partly on the basis of DIN ISO 21940 Part 12, Supplement 1. For practical application, the difficult choice of compensation planes and the relevant bending eigenmodes is explained by means of examples.

This book provides a systematic and standardized approach based on the authors' over 30 years of research experience with weight function methods, as well as the relevant literature. Fracture mechanics has become an indispensable tool for the design and safe operation of damage-tolerant structures in many important technical areas. The stress intensity factor-the characterizing parameter of the crack tip field-is the foundation of fracture mechanics analysis. The weight function method is a powerful technique for determining stress intensity factors and crack opening displacements for complex load conditions, with remarkable computational efficiency and high accuracy.The book presents the theoretical background of the weight function methods, together with a wealth of analytical weight functions and stress intensity factors for two- and three-dimensional crack geometries; many of these have been incorporated into national, international standards and industrial codes of practice. The accuracy of the results is rigorously verified, and various sample applications are provided. Accordingly, the book offers an ideal reference source for graduate students, researchers, and engineers whose work involves fracture and fatigue of materials and structures, who need not only stress intensity factors themselves but also efficient and reliable tools for obtaining them.

This book acts as a guide to simple models that describe some of the complex fluid dynamics, heat/mass transfer and combustion processes in droplets and sprays. Attention is focused mainly on the use of classical hydrodynamics, and a combination of kinetic and hydrodynamic models, to analyse the heating and evaporation of mono- and multi-component droplets. The models were developed for cases when small and large numbers of components are present in droplets. Some of these models are used for the prediction of time to puffing/micro-explosion of composite water/fuel droplets - processes that are widely used in combustion devices to stimulate disintegration of relatively large droplets into smaller ones. The predictions of numerical codes based on these models are validated against experimental results where possible. In most of the models, droplets are assumed to be spherical; some preliminary results of the generalisation of these models to the case of non-spherical droplets, approximating them as spheroids, are presented.

This monograph provides a complete and up-to-date examination of rigid body dynamics using a Lagrangian approach. All known integrable cases, which were previously scattered throughout the literature, are collected here for convenient reference. Also contained are particular solutions to diverse problems treated within rigid body dynamics.The first seven chapters introduce the elementary dynamics of the rigid body and its main problems. A full historical account of the discovery and development of each of the integrable cases is included as well. Instructors will find this portion of the book well-suited for an undergraduate course, having been formulated by the author in the classroom over many years.The second part includes more advanced topics and some of the author's original research, highlighting several unique methods he developed that have led to significant results. Some of the specific topics covered include the twelve known solutions of the equations of motion in the classical problem, which has not previously appeared in English before; a collection of completely new integrable cases; and the motion of a rigid body around a fixed point under the action of an asymmetric combination of potential and gyroscopic forces.Rigid Body Dynamics will appeal to researchers in the area as well as those studying dynamical and integrable systems theory.