Download or read book Analysis of the mechanical response of impact loaded composite sandwich structures with focus on foam core shear failure written by Tim Berend Block and published by Logos Verlag Berlin GmbH. This book was released on 2014 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sandwich structures are an economically and structurally efficient way of designing large integral composite parts. In the aerospace industry pre-impregnated face sheets and honeycomb core structures can be considered as industry standard while e.g. naval structures and wind turbine blades typically use vacuum infusion technology with polymer foam cores. Application of the less costly infusion technology in the aeronautical industry requires a thorough understanding of the damage tolerance including low velocity impact as a frequent source of damaging events. At low impact energies damage in composite foam core sandwich structures is limited to core crushing and local face sheet delaminations. Higher impact energies may initiate the competing failure modes face sheet rupture and core shear failure depending on impact, geometric and material parameters. Face sheet rupture leads to severe local damage with typically good visibility, while core shear failure leads to cracks and rear face sheet debonding of the foam core with less visibility. This work investigates the low velocity impact response of sandwich structures with carbon fiber reinforced plastic (CFRP) face sheets and a polymeric foam core using experiments at room temperature and at -55° Celsius. An analytically derived failure mode map is presented as a simple tool for design guidelines while the explicit finite element method is applied for a more detailed description of the sandwich impact process. Both models are used to analyze the impact response and describe relevant sensitivity parameters of sandwich structures.

Download or read book Analysis of the mechanical performance of pin reinforced sandwich structures written by Mohamed Adli Dimassi and published by Logos Verlag Berlin GmbH. This book was released on 2019-11-15 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rising demand to reduce fuel consumption and the continuous increase of materials and manufacturing costs has obliged aircraft manufacturers to boost the use of composite materials and to optimise the manufacturing methods. Foam core sandwich structures combine the advantages of high bending properties with low manufacturing costs when liquid composite processes are used. However, the use of foam core sandwich structures is not widespread in aircraft applications due to the better weight-specific performance of honeycomb cores and the susceptibility to impact loading. In this context, pin reinforcements are added to the foam core to improve its mechanical properties and its damage tolerance. This work contributes to the understanding of the mechanical behaviour of pin-reinforced foam core sandwich structures under static and impact loading. Ultrasonic scan and micro-computed tomography are used to identify the different damage modes. The effect of very low temperature on the damage behaviour under impact loading is investigated. An explicit simulation model to predict the impact response of pin-reinforced foam core sandwich structures is also proposed.

Download or read book Structural and Failure Mechanics of Sandwich Composites written by L.A. Carlsson and published by Springer Science & Business Media. This book was released on 2011-04-26 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Structural and Failure Mechanics of Sandwich Composites" by Leif A. Carlsson and George A. Kardomateas focuses on some important deformation and failure modes of sandwich panels such as global buckling, wrinkling and local instabilities, and face/core debonding. The book also provides the mechanics background necessary for understanding deformation and failure mechanisms in sandwich panels and the response of sandwich structural parts to a variety of loadings. Specifically, first-order and high-order sandwich panel theories, and three-dimensional elasticity solutions for the structural behavior outlined in some detail. Elasticity analysis can serve as a benchmark for judging the accuracy of simplified sandwich plate, shell and beam theories. Furthermore, the book reviews test methods developed for the characterization of the constituent face and core materials, and sandwich beams and plates. The characterization of face/core debonding is a major topic of this text, and analysis methods based on fracture mechanics are described and applied to several contemporary test specimens. Test methods and results documented in the literature are included and discussed. The book will benefit structural and materials engineers and researchers with the desire to learn more about structural behavior, failure mechanisms, fracture mechanics and damage tolerance of sandwich structures.

Download or read book A rapid virtual autoclave for carbon fiber reinforced plastics written by Junhong Zhu and published by Logos Verlag Berlin GmbH. This book was released on 2023-01-26 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural carbon fiber reinforced plastic parts are usually manufactured through autoclave processing for high-performance aerospace applications. Today’s aerospace composite manufacturing techniques require high quality with robust manufacturing processes. Manufacturing process simulation enables the investigations of physical effects and manufacturing process mechanisms. This approach has been increasingly used to predict and optimize the manufacturing process for high part quality at low manufacturing costs. Owing to a complicated manufacturing environment involving multi-physics characteristics, there is a critical need to develop an efficient and cost-effective numerical methodology with a systematic study. This thesis contributes to the systematic investigations of the process modeling, simulation, thermal measurement, and optimization in composite manufacturing of autoclave processing. The method provides a correct and efficient thermal analysis and optimization in autoclave processing to achieve better process control and ensure the quality of composite parts. The presented framework can be applied directly in autoclave production with larger dimensions and full-scale tools for aerospace structures. The developed methodology allows quick delivery guidelines of production plans and optimization strategies for composite manufacturing in a highly useful and cost-effective way, thereby reducing the cost in the design and manufacturing phase. Since July 2017, Mr. Junhong Zhu has been working as a research assistant in the department of modeling and simulation at the FIBRE (Faserinstitut Bremen e.V.) at the University of Bremen. He deals with the process modeling and simulation in composite manufacturing of autoclave processing. His research focuses on numerical methods, such as computational fluid dynamics and finite element methods, muti-physics coupling schemes, and process optimization. He is also interested in the use of artificial intelligence in the manufacturing process.

Download or read book Dynamic Failure of Composite and Sandwich Structures written by Serge Abrate and published by Springer Science & Business Media. This book was released on 2012-11-02 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a broad view of the current state of the art regarding the dynamic response of composite and sandwich structures subjected to impacts and explosions. Each chapter combines a thorough assessment of the literature with original contributions made by the authors. The first section deals with fluid-structure interactions in marine structures. The first chapter focuses on hull slamming and particularly cases in which the deformation of the structure affects the motion of the fluid during the water entry of flexible hulls. Chapter 2 presents an extensive series of tests underwater and in the air to determine the effects of explosions on composite and sandwich structures. Full-scale structures were subjected to significant explosive charges, and such results are extremely rare in the open literature. Chapter 3 describes a simple geometrical theory of diffraction for describing the interaction of an underwater blast wave with submerged structures. The second section addresses the problem of impact on laminated composite structures with chapters devoted to ballistic impacts on pre-stressed composite structures, tests developed to simulate dynamic failure in marine structures, damage mechanisms and energy absorption in low velocity impacts, perforation, the numerical simulation of intra and inter-ply damage during impact, and hail impact on laminated composites. Sandwich structures with laminated facings are considered in Section 3 with chapters dealing with the discrete modeling of honeycomb core during the indentation of sandwich structures, the behavior of fold core sandwich structures during impact, and impact on helicopter blades. The fourth section consists of two chapters presenting experimental results and numerical simulation of composite structures subjected to crash. This volume is intended for advanced undergraduate and graduate students, researchers, and engineers interested and involved in analysis and design of composite structures.

Download or read book Sandwich Structures 7 Advancing with Sandwich Structures and Materials written by O.T. Thomsen and published by Springer Science & Business Media. This book was released on 2006-01-16 with total page 1029 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sandwich structures represent a special form of a laminated composite material or structural elements, where a relatively thick, lightweight and compliant core material separates thin stiff and strong face sheets. The faces are usually made of laminated polymeric based composite materials, and typically, the core can be a honeycomb type material, a polymeric foam or balsa wood. The faces and the core are joined by adhesive bonding, which ensures the load transfer between the sandwich constituent parts. The result is a special laminate with very high bending stiffness and strength to weight ratios. Sandwich structures are being used successfully for a variety of applications such as spacecraft, aircraft, train and car structures, wind turbine blades, boat/ship superstructures, boat/ship hulls and many others. The overall objective of the 7th International Conference on Sandwich Structures (ICSS-7) is to provide a forum for the presentation and discussion of the latest research and technology on all aspects of sandwich structures and materials, spanning the entire spectrum of research to applications in all the fields listed above.

Download or read book Dynamic Behavior of Materials Volume 1 written by Vijay Chalivendra and published by Springer Science & Business Media. This book was released on 2012-09-27 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic Behavior of Materials, Volume 1: Proceedings of the 2012 Annual Conference on Experimental and Applied Mechanics represents one of seven volumes of technical papers presented at the Society for Experimental Mechanics SEM 12th International Congress & Exposition on Experimental and Applied Mechanics, held at Costa Mesa, California, June 11-14, 2012. The full set of proceedings also includes volumes on Challenges in Mechanics of Time -Dependent Materials and Processes in Conventional and Multifunctional Materials, Imaging Methods for Novel Materials and Challenging Applications, Experimental and Applied Mechanics, 2nd International Symposium on the Mechanics of Biological Systems and Materials 13th International Symposium on MEMS and Nanotechnology and, Composite Materials and the 1st International Symposium on Joining Technologies for Composites.

Download or read book Impact of Sandwich Structures written by Jianxun Zhang and published by Scientific Research Publishing, Inc. USA. This book was released on 2024-03-11 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book focuses on the impact response of lightweight sandwich structures. As a kind of lightweight structure, sandwich structure has been widely used in various engineering fields, such as aerospace, ships, vehicles and so on, because of its high specific stiffness, high specific strength and versatility. During service, the sandwich structures may be subjected to various impact loads, which may result in serious damage, thereby reducing the stiffness, strength and load-bearing ca-pacity, thereby shortening the service life and bringing safety hazards. Therefore, an in-depth understanding of impact behavior and failure mechanisms is of great significance for the wider application of sandwich structures. In the past decades, many scholars have conducted in-depth research on related topics. But it is difficult for readers to systematically read all the literature in a short time. This book seeks to succinctly summarize the development and the results achieved in this field. This book focuses on simple, classical structures, such as beams, plates, and shells, under loads such as low-velocity impact, explosive load, and bullet penetrations. The main research methods are theoretical analysis, numerical simulation and experimental investigation. The purpose is to reveal the deep mechanism and lay a foundation for the application of sandwich structure in engineering practice.

Download or read book Experimental Analysis of Nano and Engineering Materials and Structures written by E.E. Gdoutos and published by Springer Science & Business Media. This book was released on 2007-12-06 with total page 1003 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains two-page abstracts of the 482 papers presented at the latest conference on the subject, in Alexandroupolis, Greece. The accompanying CD contains the full length papers. The abstracts of the fifteen plenary lectures are included at the beginning of the book. The remaining 467 abstracts are arranged in 23 tracks and 28 special symposia/sessions with 225 and 242 abstracts, respectively. The papers of the tracks have been contributed from open call, while the papers of the symposia/sessions have been solicited by the respective organizers.

Download or read book Woven Fabric Composites written by Niranjan K. Naik and published by CRC Press. This book was released on 1993-11-27 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is presented as an analytical methodology developed to study the thermo-elastic behavior of woven fabric composites. Also, experimental studies on the failure behavior of woven fabric composites are presented.

Download or read book The Low Velocity Impact Response of Sandwich Structures written by Mohamad Hassan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the mechanical properties and fracture behaviour of a range of core materials have been investigated in order to elucidate the impact properties of sandwich structures. Initially, the compression properties of the core have been evaluated at quasi-static and impact rates of strain. It has been shown that the plastic collapse strength of the cores is highly rate-sensitive, increasing by up to one hundred percent in passing from quasi-static to dynamic rates of loading. Subsequently, the SENB (Mode I) and shear (Mode II) fracture properties of the polymer foams were evaluated. Mode I tests have shown that the crosslinked PVC foams and the PET foams fail in a brittle manner, however, the linear PVC foams fail in a ductile mode. Here, it has been shown that the Mode II shear toughnesses of the crosslinked PVC foams were up to thirty-five times greater than their corresponding Mode I values. Following this, a series of indentation tests were conducted on polymer-foam sandwich structures and their response was characterised using a Meyer indentation law of the form P = Can. It has been shown that the value of the exponent parameter, n, does not vary significantly with the properties of the core or the skin, typically being close to unity for all tests. The contact stiffness, C, was found to depend on the plastic collapse strength of the foam, the indentor radius and the properties of the skin. It has been shown that a plot of contact stiffness against plastic collapse strength, containing all of the quasi-static and dynamic data, appears to yield a unique curve. Subsequently, the perforation resistances of a range of foam-based sandwich structures were investigated. The influence of the plastic collapse stress of the foam in determining the failure thresholds of the front and rear composite skins has been established. Here, a simple model has been used to successfully predict failure of the top surface composite skin in the sandwich structures. In addition, the force associated with perforating the lightweight core has been shown to be strongly dependent on the shear strength of the polymer foam. The perforation response of sandwich structures based on fully-recyclable materials has also been investigated. The design of the SRPP skin has a significant effect on the energy-absorbing characteristics of the sandwich structure, with the performance of systems based on multiple layer skins greatly exceeding that associated with a monolithic skin. It has been shown that when normalised by the areal density of the panels, those sandwich structures with multiple layer skins out-perform systems with monolithic skins as well as conventional GFRP/aluminium honeycomb sandwich structures.

Download or read book Failure in Composites written by Anthony M. Waas and published by DEStech Publications, Inc. This book was released on 2013 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fourth volume of the ASC series on advanced composites contains critical information on static and dynamic composite failure and how it is predicted and modeled using novel computational methods and micromechanical analysis.

Download or read book An Introduction to Sandwich Construction written by Dan Zenkert and published by Twayne Publishers. This book was released on 1995 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact Performance and Bending Behavior of Composite Sandwich Structures in Cold Temperature Arctic Condition written by Md. Mahfujul H. Khan and published by . This book was released on 2020 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigates experimental impact performance, underlyingdamage mechanisms and post-impact flexural strength of Carbon fiber-reinforced polymer face sheets with PVC foam core sandwich panel in cold temperature Arctic conditions. Analytical and statistical predictions on post-impact bending behaviour is further validated with the experimental results. A series of low-velocity impact tests were performed using an instrumented falling weight test system at room and low temperatures. Exposure to low temperature degrades the damage tolerance of the CFRP face sheet at higher loads significantly. Post-mortem inspection using X-ray micro-computed tomography elucidates complex failure mechanisms in the CFRP composite face sheets (matrix crack, delamination, and fiber breakage) and foam core (core crushing, core shearing and interfacial debonding). Post-impact flexural behavior is analyzed for CFRP-PVC sandwich panels. Bending test results elucidated that properties are more sensitive to the in-plane compressive property of the CFRP face sheet than in-plane tensile property. Specifically, the degradation of flexural strength strongly depends on existing prebend damage due to impact loading. Statistical analyses are employed to demonstrate that flexural performance is mainly governed by face sheet thickness and pre-bend impact energy. Analytical predictions on flexural collapse modes for CFRP-PVC reveal indentation, core shear and face wrinkling as the main competing failure modes, whereby the dominant mechanism is dependent on preexisting impact damage, face sheet thickness, environmental temperature, and bending configuration. Results portray that thick face sheet specimens collapse mainly by indentation or core shear. However, thin face sheet specimens display novel collapse mechanisms such as core tensile failure and debonding. Core tensile failure is attributed to the degraded tensile strength of back face sheet at extreme low temperatures. The final part of this work further explores a comparative analysis on the impact behavior and underlying damage mechanics between Carbon fiber reinforced polymer (CFRP), Glass fiber reinforced polymer (GFRP) and Carbon-Glass fiber hybrid face sheet to PVC foam core sandwich panel. Force displacement and energy absorbed (%) results revealed that fiber hybridization leads to better impact resistance compared to CFRP-PVC, particularly at low temperatures. The extent of core damage namely core crushing and core shearing is also reduced when carbon fibers are hybridized with glass fibers. Impacted face sheet damage mechanism switches from severe fiber breakage (CFRP-PVC) to extensive delamination (Hybrid-PVC). Moreover, distal back face sheet splitting(CFRP-PVC) is hindered for the Carbon-Glass fiber hybrid face sheet sandwich panel.

Download or read book Dynamic Response and Failure of Composite Materials and Structures written by Valentina Lopresto and published by Woodhead Publishing. This book was released on 2017-05-17 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic Response and Failure of Composite Materials and Structures presents an overview of recent developments in a specialized area of research with original contributions from the authors who have been asked to outline needs for further investigations in their chosen topic area. The result is a presentation of the current state-of-the art in very specialized research areas that cannot be found elsewhere in the literature. For example, Massabò presents a newly developed theory for laminated composite plates that accounts for imperfect bonding between layers with new solutions for problems involving thermal effects. This theory is new and computationally-efficient, and the author describes how it fits in the broader context of composite plate theory. Abrate discusses the design of composite marine propellers and presents a detailed derivation of the equations of motion of a rotating blade, including centrifugal effects and the effects of pre-twisting and other geometric parameters. This book is a major reference resource for academic and industrial researchers and designers working in aerospace, automotives, and the marine engineering industry. - Presents recent developments in a research field that has experienced tremendous advances because of improved computational capabilities, new materials, and new testing facilities - Includes contributions from leading researchers from Europe and the USA who present the current state-of-the-art, including unique and original research - Provides extensive experimental results and numerical solutions - Appeals to a broad range of professional researchers working in aerospace, automotive, and marine engineering fields

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1979 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blast and Ballistic Loading of Structures written by John Hetherington and published by CRC Press. This book was released on 2014-04-21 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together, in a concise format, the key elements of the loads produced from explosive sources, and how they interact with structures. Explosive sources include gas, high explosives, dust and nuclear materials.It presents quantitative information and design methods in a useable form without recourse to extensive mathematical ana