1,721,094 research outputs found
Structural and Computational Mechanics Book Series
No full textThe Esculapio Series in “Structural and Computational Mechanics” has been inaugurated with the aim of arranging a series of books in these key fields related to academic research, education and industrial applications. The Esculapio Series publishes high- level texts for academic students, deep studies on good practice and industrial technology, interesting and fundamental research topics related to industrial development and engineering practices. The readership encapsulates undergraduate and PhD students, researchers, scientists and free-lancers within applied mechanics topics. Civil/structural, mechanical, aerospace, naval, nuclear, automotive, materials, environmental, electrical, and biomedical engineers could benefit from this book series. The present book series would be the natural home for authors proficient in mechanics of materials, mechanics of structures as well as computational and applied mechanics. The Esculapio Series will focus on the following research areas, but not limited to: - Applied mechanics - Applied mathematics - Computational mechanics - Theoretical modeling - Engineering structures - Typical materials: concrete, metal, wood, masonry, etc. - Classical and advanced numerical methods - Composite Materials - Nonlinearities - Repair and reinforcements - Meta-materials and advanced materials - SMART structural component
Curved and Layered Structures
No full textThe aim of Curved and Layered Structures is to become a premier source of knowledge and a worldwide-recognized platform of research and knowledge exchange for scientists of different disciplinary origins and backgrounds (e.g., civil, mechanical, marine, aerospace engineers and architects). The journal publishes research papers from a broad range of topics and approaches including structural mechanics, computational mechanics, engineering structures, architectural design, wind engineering, aerospace engineering, naval engineering, structural stability, structural dynamics, structural stability/reliability, experimental modeling and smart structures. Therefore, the Journal accepts both theoretical and applied contributions in all subfields of structural mechanics as long as they contribute in a broad sense to the core theme
Structural and Computational Mechanics Book Series
No full textThe Esculapio Series in “Structural and Computational Mechanics” has been inaugurated with the aim of arranging a series of books in these key fields related to academic research, education and industrial applications. The Esculapio Series publishes high- level texts for academic students, deep studies on good practice and industrial technology, interesting and fundamental research topics related to industrial development and engineering practices. The readership encapsulates undergraduate and PhD students, researchers, scientists and free-lancers within applied mechanics topics. Civil/structural, mechanical, aerospace, naval, nuclear, automotive, materials, environmental, electrical, and biomedical engineers could benefit from this book series. The present book series would be the natural home for authors proficient in mechanics of materials, mechanics of structures as well as computational and applied mechanics. The Esculapio Series will focus on the following research areas, but not limited to: - Applied mechanics - Applied mathematics - Computational mechanics - Theoretical modeling - Engineering structures - Typical materials: concrete, metal, wood, masonry, etc. - Classical and advanced numerical methods - Composite Materials - Nonlinearities - Repair and reinforcements - Meta-materials and advanced materials - SMART structural component
Dynamic stability of doubly-curved multilayered shells subjected to arbitrarily oriented angular velocities: Numerical evaluation of the critical speed
No full textThe paper is focused on the evaluation of the critical speed of rotating doubly-curved multilayered shell structures. The theoretical framework developed to this aim is based on a general formulation capable to define several Higher-order Shear Deformation Theories (HSDTs) in a unified manner. The current approach can deal easily with angular velocities applied about a generic axis of the structure. This aspect represents a clear advancement with respect to the formulations available in the literature, which are developed mainly to investigate the dynamic behavior of rotating shells of revolution (disks, circular cylinders and conical shells), in which the angular velocity is applied about their revolution axis. It is important to underline that the effects of both Coriolis and centripetal accelerations on the dynamic response of shell structures, characterized by various geometric shapes, are included in the model. The quadratic eigenvalue problem that lies behind the free vibration analysis in hand is solved numerically by means of the well-known Generalized Differential Quadrature (GDQ) method. The critical speed is obtained as a result of many parametric investigations, which are defined for increasing values of the applied angular velocities. Finally, it should be mentioned that the current research falls within the aim of the study of the dynamic stability of rotating structures. For this purpose, several considerations concerning the flutter and divergence phenomena are presented
Mechanics of Innovative Materials in Engineering Applications
No full textIn the last few decades, many engineers and researchers have dedicated their efforts to develop new classes of composite materials that can be used in the manufacture of aerospace components, aircrafts, boat hulls and sails, car bodies, long span roofs, as well as biomedical prostheses, electronic devices, and drones. It is evident that the structural elements that could be employed in these fields require peculiar features that composite materials can provide more than conventional constituents, such as isotropic mediums. Unidirectional fiber-reinforced composites represent one of the most characteristics materials that are currently used for these purposes. Nevertheless, it should be mentioned that advanced configurations of these mediums have attracted the attentions of many researchers, so that curvilinear fibers and their arbitrarily graded placements have been applied to achieve improved structural responses. These concepts fall within the topic of Variable Angle Tow (VAT) and Functionally Graded (FG) composites, respectively. Due to the advancements in the nanotechnologies, the reinforcing phases of composite materials can be applied at the nanoscale level. It is well-known that Carbon Nanotubes (CNTs) can improve the mechanical behavior of these composites because of their remarkable physical and chemical features. As proven by the enormous number of papers available in the pertinent literature, these kinds of nanostructures represent one of the most exploited innovative mediums. Enhanced mechanical features can be also obtained by designing materials and structures with particular geometries. This class of advanced components known as lattice-based metamaterials provides peculiar properties that could be exploited in several engineering fields. Analogously, tensegrity structures and pre-stressed lattices should be mentioned for the same purpose. In addition, various applications have been presented in literature to model SMART materials and SMART-structured systems. Examples of SMART applications involve large stroke SMART actuators, piezoelectric sensors, shape memory alloys, magnetostrictive and electrostrictive materials, as well as auxetic components. These particular constituents can be included in the lamination schemes of SMART structures to control and monitor the vibrational behavior or the static deflection of several composites. All things considered, the main aim of this Special Issue is to collect various investigations focused on the mechanical analysis of composite structures and materials. Numerical analyses, analytical solutions, and experimental studies involving these composites are welcomed. Authors are encouraged to present unconventional constitutive laws and innovative homogenization techniques, advanced mechanical configurations, as well as multiscale approaches, to provide a complete framework on these groundbreaking materials and facilitate their use in different engineering applications
Free vibrations and bending of laminated thin plates with distorted domains in gradient elasticity: an isoparametric finite element formulation based on Hermite mapping
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Foam core composite sandwich plates and shells with variable stiffness: Effect of the curvilinear fiber path on the modal response
No full textThis paper presents the free vibration analysis of composite sandwich plates and doubly-curved shells with variable stiffness. The reinforcing fibers are located in the external skins of the sandwich structures according to curved paths. These curvilinear paths are described by a general expression that combines power-law, sinusoidal, exponential, Gaussian and ellipse-shaped functions. As a consequence, the reinforcing fibers are placed in these orthotropic layers in an arbitrary manner, in order to achieve the desired mechanical properties. The effect of this variable fiber orientation on the natural frequencies is investigated by means of several parametric studies. As far as the structural theory is concerned, an Equivalent Single Layer (ESL) approach based on the well-known Carrera Unified Formulation (CUF) is employed. The Murakami’s function is added to the kinematic model to capture the zig-zag effect, when the soft-core effect is significant. Thus, several Higher-order Shear Deformation Theories (HSDTs) are taken into account in a unified manner. The differential geometry is employed to describe the reference surface of doubly-curved shells and panels, which are characterized by variable radii of curvature. The numerical solution is obtained using the Generalized Differential Quadrature (GDQ) method, due to its accuracy and stability features. The present solution is compared with the results available in the literature or obtained by finite element commercial code
On the mechanics of laminated doubly-curved shells subjected to point and line loads
No full textIt is well-known that the implementation of concentrated forces, such as point and line loads, represents a challenging task, especially from the computational point of view, since a strong discontinuity has to be inserted in the structural model. The present paper aims to solve the static problem of laminated composite doubly-curved shell structures subjected to concentrated loads employing the Generalized Differential Quadrature (GDQ) as numerical tool, according to what has been shown by the authors in their previous work. Its accuracy and reliability features are proven for several grid distributions when the concentrated loads are modeled through the Dirac-delta function. The theoretical framework on which this approach is based is the Unified Formulation developed by Carrera, which allows to investigate several Higher-order Shear Deformation Theories (HSDTs). The differential geometry is used to describe accurately the reference surface of various doubly-curved shell structures. The validity of the current approach is shown comparing the GDQ results with the exact and semi-analytical results available in the literature. A posteriori recovery procedure based on the three-dimensional equilibrium equations for a shell structure is introduced to compute the through-the-thickness variation of strain, stress and displacement components by means of the GDQ method
Advanced Laminated Composite Applications for Doubly-Curved Shell Structural Components with Variable Curvature
No full textTheoretical modeling of laminated composite shells is a wide-ranging topic that falls out into different engineering branches. Shell structural components can be found in civil, mechanical, naval and aerospace engineering as roofs, hoods, hulls, wings and cockpits, respectively. The studies over doubly-curved shells have been growing, because the use of advanced and ground-breaking materials have hitherto been increasing. These studies have a direct and immediate application due to the great advantages in terms of weight loss and enhanced strength that these new materials have, when compared to classic applications. However classic theoretical modeling cannot be considered when laminated composite structures are analyzed. Because the high anisotropic behavior of these structures is not predicted accurately using the well-known thin shells theories. Most of the times, higher-order equivalent single layer and layer-wise approaches have to be introduced to accurately capture the mechanical behavior of these components and to avoid the computational inefficiency of the 3D elasticity. Due to their complexity laminated composite shells can be hardly studied using exact and semi-analytical solutions, since only a few configurations can be solved. Generally speaking the finite element method is the most wide-spread tool for the numerical computation of these structures. Commercial finite element implementations approximate the geometry of a generic component using flat plates that only get close to the physical shape. For this reason the present implementation employs a differential geometry description for the numerical design of doubly-curved structures when variable radii of curvatures are present. Since the geometric parameters change point by point an advanced collocation method is carried out. The present procedure results to be stable, accurate and reliable with respect to other numerical approaches. Both the free vibration and the static problems will be discussed with a particular emphasis on the stress and strain recovery procedure, which is a major problem for the evaluation of through-the-thickness quantities of laminated composite shell structures
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