This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

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Cellulose nanomaterials review: structure, properties and nanocomposites

This work presents the analytic and experimental development of piezoelectric actuators as elements of intelligent structures, i.e., structures with highly distributed actuators, sensors, and processing networks. Static and dynamic analytic models are derived for segmented piezoelectric actuators that are either bonded to an elastic substructure or embedded in a laminated composite. These models lead to the ability to predict, a priori, the response of the structural member to a command voltage applied to the piezoelectric and give guidance as to the optimal location for actuator placement. A scaling analysis is performed to demonstrate that the effectiveness of piezoelectric actuators is independent of the size of the structure and to evaluate various piezoelectric materials based on their effectiveness in transmitting strain to the substructure. Three test specimens of cantilevered beams were constructed: an aluminum beam with surface-bonded actuators, a glass/epoxy beam with embedded actuators, and a graphite/epoxy beam with embedded actuators. The actuators were used to excite steady-state resonant vibrations in the cantilevered beams. The response of the specimens compared well with those predicted by the analytic models. Static tensile tests performed on glass/epoxy laminates indicated that the embedded actuator reduced the ultimate strength of the laminate by 20%, while not significantly affecting the global elastic modulus of the specimen.

Use of piezoelectric actuators as elements of intelligent structures

This paper provides an overview of recent progress made in the area of cellulose nanofibre-based nanocomposites. An introduction into the methods used to isolate cellulose nanofibres (nanowhiskers, nanofibrils) is given, with details of their structure. Following this, the article is split into sections dealing with processing and characterisation of cellulose nanocomposites and new developments in the area, with particular emphasis on applications. The types of cellulose nanofibres covered are those extracted from plants by acid hydrolysis (nanowhiskers), mechanical treatment and those that occur naturally (tunicate nanowhiskers) or under culturing conditions (bacterial cellulose nanofibrils). Research highlighted in the article are the use of cellulose nanowhiskers for shape memory nanocomposites, analysis of the interfacial properties of cellulose nanowhisker and nanofibril-based composites using Raman spectroscopy, switchable interfaces that mimic sea cucumbers, polymerisation from the surface of cellulose nanowhiskers by atom transfer radical polymerisation and ring opening polymerisation, and methods to analyse the dispersion of nanowhiskers. The applications and new advances covered in this review are the use of cellulose nanofibres to reinforce adhesives, to make optically transparent paper for electronic displays, to create DNA-hybrid materials, to generate hierarchical composites and for use in foams, aerogels and starch nanocomposites and the use of all-cellulose nanocomposites for enhanced coupling between matrix and fibre. A comprehensive coverage of the literature is given and some suggestions on where the field is likely to advance in the future are discussed.

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Review: current international research into cellulose nanofibres and nanocomposites

Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics

The numerical implementation of the model of brittle fracture developed in Francfort and Marigo (1998. J. Mech. Phys. Solids 46 (8), 1319–1342) is presented. Various computational methods based on variational approximations of the original functional are proposed. They are tested on several antiplanar and planar examples that are beyond the reach of the classical computational tools of fracture mechanics.

Numerical experiments in revisited brittle fracture

The combination of materials to form a new material system with enhanced material properties is a well documented historical fact. For example, the ancient Jewish workers during their tenure under the Pharaohs used chopped straws in bricks as a means of enhancing their structural integrity. The Japanese Samurai warriors were known to use laminated metals in the forging of their swords to obtain desirable material properties. Even certain artisans from the Mediterranean and Far East used a form of composite technology in molding art works which were fabricated by layering cut paper in various sizes for producing desired shapes and contours.

Introduction To Composite Materials

Preface to the Second Edition. Preface to the First Edition. 1. Introduction to Composite Materials. 2. Anisotropic Elasticity and Composite Laminate Theory. 3. Plates and Panels of Composite Materials. 4. Beams, Columns and Rods of Composite Materials. 5. Composite Material Shells. 6. Energy Methods For Composite Material Structures. 7. Strength and Failure Theories. 8. Joining of Composite Material Structures. 9. Introduction to Composite Design. Appendices: A-1. Micromechanics. A-2. Test Standards for Polymer Matrix Composites. A-3. Properties of Various Polymer Composites. Author Index. Subject Index.

The behavior of structures composed of composite materials

SANDWICH STRUCTURES: ORIGINS, ADVANTAGES, AND USES Description of Various Sandwich Constructions Advantages of Sandwich Construction over Construction Monocoque Thin Walled Construction Origins of Sandwich Construction Uses of Sandwich Construction Present Approach to Analysis Problems References ANISTROPIC ELASTICITY AND COMPOSITE LAMINATE THEORY Introduction Derivation of the Anisotropic Elastic Stiffness and Compliance Matrices The Physical Meaning of the Components of the Orthotropic Elasticity Tensor Methods to Obtain Composite Elastic Properties from Fiber and Matrix Properties Thermal and Hygrothermal Considerations Time-Temperature Effects on Composite Materials High Strain Rate Effects on Material Properties Laminae of Composite Materials Laminate Analysis [A], [B], and [D] Stiffness Matrices for a Mid-Plane Symmetric Sandwich Structure Piezoelectric Effects Problems References DERIVATION OF THE GOVERNING EQUATIONS FOR SANDWICH PLATES (PANELS) Introduction Plate Equilibrium Equations The Bending of Composite Material Laminated and/or Sandwich Plates: Classical Theory Classical Plate Theory Boundary Conditions Analysis of Composite Materials Laminated and/or Sandwich Panels Including Transverse Shear Deformation Effects Boundary Conditions for a Plate Using the Refined Plate Theory Laminated or Sandwich Plate on an Elastic Foundation Laminated or Sandwich Plates Subjected to Dynamic Loads Problems References BEAMS, COLUMNS, AND RODS OF COMPOSITE MATERIALS Development of Classical Beam Theory Some Simplified Sandwich-Beam Solutions Eigenvalue Problems of Sandwich Beams: Natural Vibrations and Elastic Stability Other Considerations Problems References ENERGY METHODS FOR SANDWICH STRUCTURES Introduction Theorem of Minimum Potential Energy Analysis of a Beam in Bending Using the Theorem of Minimum Potential Energy Reissner's Variational Theorem and Its Applications Static Deformation of Moderately Thick Beams Flexural Vibrations of Moderately Thick Beams Flexural Natural Frequencies of a Simply Supported Beam Including Transverse Shear Deformation and Rotatory Inertia Effects Minimum Potential Energy for Rectangular Plates A Rectangular Composite Material Plate Subjected to Lateral and Hygrothermal Loads In-Plane Shear Strength Determination of Composite Materials in Laminated and Sandwich Panels Problems References SOLUTIONS FOR RECTANGULAR SANDWICH PLATES Introduction Navier Solutions for Rectangular Sandwich Plates Levy Solutions for Plates of Composite Materials Perturbation Solutions for the Bending of a Composite Material Sandwich Plate, with Mid-Plane Symmetry and No Bending-Twisting Coupling Isotropic Sandwich Panels Subjected to a Uniform Lateral Load Minimum Weight Optimization for a Sandwich Panel Subjected to a Distributed Lateral Load Analysis of an Isotropic Sandwich Plate on an Elastic Foundation Subjected to a Uniform Lateral Load Static Analysis of Sandwich Plates of Composite Materials Including Transverse Shear Deformation Effects Exact Solution Other Considerations Problems References DYNAMIC EFFECTS ON SANDWICH PANELS Introduction Natural Flexural Vibrations of Sandwich Plates: Classical Theory Natural Flexural Vibrations of Sandwich Plates Including Transverse Shear Deformation Effects Forced-Vibration Response of a Sandwich Plate Subjected to a Dynamic Lateral Load Dynamic Response of Sandwich Plates to Localized Loads Large Amplitude Nonlinear Oscillations of Sandwich Plates Simply Supported on All Edges Linear and Nonlinear Oscillations of Specially Orthotropic Sandwich Panels with Various Boundary Conditions Vibration Damping Problems References THERMAL AND MOISTURE EFFECTS ON SANDWICH STRUCTURES General Considerations Derivation of the Governing Equations for a Thermoplastic Isotropic Plate Boundary Conditions General Treatment of Plate Nonhomogeneous Boundary Conditions Thermoelastic Effects on Beams Self-Equilibrium of Thermal Stress Rectangular Composite Material Plate Subjected to Lateral and Hygrothermal Loads References ELASTIC INSTABILITY (BUCKLING) OF SANDWICH PANELS General Considerations The Buckling of an Orthotropic Sandwich Plate Subjected to In-Plane Loads Classical Theory Elastic Stability of a Composite Sandwich Panel Including Transverse Shear Deformation and Hygrothermal Effects The Buckling of an Isotropic Plate on an Elastic Foundation Subjected to Biaxial In-Plane Compressive Loads The Buckling of Honeycomb Core Sandwich Panels Subjected to In-Plane Compressive Loads The Buckling of Solid- or Foam-Core Sandwich Panels Subjected to In-Plane Compressive Loads Buckling of a Truss-Core Sandwich Panel Subjected to Uniaxial Compression Elastic Stability of a Web-Core Sandwich Panel Subjected to a Uniaxial Compressive In-Plane Load Buckling of Honeycomb-Core Sandwich Panels Subjected to In-Plane Shear Loads Buckling of Solid-Core or Foam-Sandwich Panel Subjected to In-Plane Shear Loads Buckling of a Truss-Core Sandwich Panel Subjected to In-Plane Shear Loads Buckling of a Web-Core Sandwich Panel Subjected to an In-Plane Shear Load Other Considerations Problems References STRUCTURAL OPTIMIZATION TO OBTAIN MINIMUM-WEIGHT SANDWICH PANELS Introduction Minimum Weight Optimization of Honeycomb-Core Sandwich Panels Subjected to a Unidirectional Compressive Load Minimum Weight Optimization of Foam-Core Sandwich Panels Subjected to a Unidirectional Compressive Load Minimum Weight Optimization of Truss-Core Sandwich Panels Subjected to a Unidirectional Compressive Load Minimum Weight Optimization of Web-Core Sandwich Panels Subjected to a Unidirectional Compressive Load Minimum Weight Optimization of Honeycomb-Core Sandwich Panels Subjected to In-Plane Shear Loads Minimum Weight Optimization of Solid- and Foam-Core Sandwich Panels Subjected to In-Plane Shear Loads Minimum Weight Optimization of Truss-Core Sandwich Panels Subjected to In-Plane Shear Loads Minimum Weight Optimization of Web-Core Sandwich Panels Subjected to In-Plane Shear Loads Optimal Stacking Sequences for Composite Material Laminate Faces for Various Sandwich Panels Subjected to Various Loads Problems References SANDWICH SHELLS Introduction Analysis of Sandwich Cylindrical Shells under Axially Symmetric Loads A General Solution for Orthotropic-Sandwich Cylindrical Shells under Axially Symmetric Loads Shells with Mid-Plane Asymmetry Other Considerations Problems References BUCKLING OF SANDWICH CYLINDRICAL SHELLS Buckling of a Solid- or Foam-Core Sandwich Cylindrical Shell with Isotropic Faces Subjected to an Axially Symmetric Compressive End Load Buckling of a Solid- or Foam-Core Sandwich Cylindrical Shell with Orthotropic Composite Faces Subjected to an Axially Symmetric Compressive Load Buckling of a Honeycomb-Core Sandwich Cylindrical Shell with Composite Faces Subjected to an Axially Symmetric Compressive End Load Overall Buckling of Sandwich Cylindrical Shells Subjected to an Overall Bending Moment Buckling of a Sandwich Cylindrical Shell Due to External Pressure Buckling of a Sandwich Cylindrical Shell Due to Torsion Dynamic Buckling Problems References MINIMUM WEIGHT OPTIMIZATION OF SANDWICH CYLINDRICAL SHELLS General Discussion Minimum Weight Optimization of a Solid Foam-Core Sandwich Cylindrical Shell with Isotropic Faces Subjected to an Axially Compressive Load Minimum Weight Optimization of a Solid- or Foam-Core Sandwich Cylindrical Shell with Orthotropic Composite Material Faces Subjected to an Axially Compressive Load Minimum Weight Optimization of a Honeycomb-Core Sandwich Cylindrical Shell with Composite Material Faces Subjected to an Axially Symmetric Compressive Load Problems References APPENDIX 1: Core Materials APPENDIX 2: Face Materials APPENDIX 3: American Society for Testing Materials (ASTM) Standards for Sandwich Structures and Materials INDEX

The Behavior of Sandwich Structures of Isotropic and Composite Materials

This book attempts to provide a basic fundamental understanding of the physical and mathematical aspects of the materials system and structures comprised of composite materials. The introduction discusses the nature and scope of composite materials, the strengthening processes used in the manufacture of alloys, and the needs for composite materials. Then various types of fiber-reinforced materials are examined, first by discussing the properties of the component phases. Next, the behavior of dispersion-strengthened and directionally solidified eutectics is considered. An introduction to plate and shell theory is given for isotropic materials, and then the stress--strain relations thus developed are extended to deal with anisotropic materials. The deformation of a fibrous composite is analyzed for plate- and shell-type structures. The strength and fracture of composite materials are discussed in the final chapter. The book is not an encyclopedia of all previous research and solutions. 136 figures, 19 tables, 492 references. (RWR)

Composite materials and their use in structures

A concise method of analysis is used to study the numerous parameters influencing the stress distribution within the adhesive of a single lap joint. The formulation includes transverse shear and normal strain deformations. Both isotropic or anisotropic material systems of similar or dissimilar adherends are analysed. Results indicate that the primary Young's modulus of the adherend, the overlap length, and the adhesive's material properties are the parameters most influential in optimizing the design of a single lap joint.

Jack R. Vinson

Papers

Introduction To Composite Materials

The behavior of structures composed of composite materials

The Behavior of Sandwich Structures of Isotropic and Composite Materials

Composite materials and their use in structures

The Efficient Design of Adhesive Bonded Joints