The Impact Response of Carbon/Epoxy Laminates (Center Director's Discretionary Fund, Project No. 94-13)

The Impact Response of Carbon/Epoxy Laminates (Center Director's Discretionary Fund, Project No. 94-13) PDF

Author: National Aeronautics and Space Adm Nasa

Publisher: Independently Published

Published: 2018-11-23

Total Pages: 180

ISBN-13: 9781790128884

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Low velocity dropweight impact tests were conducted on carbon/epoxy laminates under various boundary conditions. The composite plates were 8-ply (+45,0, -45,90)s laminates supported in a clamped-clamped/free-free configuration with varying amounts of in-plane load, N(sub x), applied. Specimens were impacted at energies of 3.4, 4.5, and 6 Joules (2.5, 3.3, and 4.4 ft-lb). The amount of damage induced into the specimen was evaluated using instrumented impact techniques, x-ray inspection, and cross-sectional photomicroscopy. Some static identation tests were performed to examine if the impact events utilized in this study were of a quasi-static nature and also to gain insight into the shape of the deflected surface at various impact load combinations. Load-displacement curves from these tests were compared to those of the impact tests, as was damage determined from x-ray inspection. The finite element technique was used to model the impact event and determine the stress field within the laminae. Results showed that for a given impact energy level, more damage was induced into the specimen as the external in-plane load, N(sub x), was increased. The majority of damage observed consisted of back face splitting of the matrix parallel to the fibers in that ply, associated with delaminations emanating from these splits. The analysis showed qualitatively the results of impact conditions on maximum load of impact, maximum transverse deflection, and first failure mode and location. Nettles, A. T. and Hodge, A. J. Marshall Space Flight Center EPOXY MATRIX COMPOSITES; LAMINATES; IMPACT TESTS; DYNAMIC TESTS; X RAY INSPECTION; STRESS DISTRIBUTION; PLATES (STRUCTURAL MEMBERS); LOADS (FORCES); FAILURE MODES; DISPLACEMENT; DEFLECTION; DAMAGE; BOUNDARY CONDITION

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF

Author:

Publisher:

Published: 1995

Total Pages: 700

ISBN-13:

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Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Dynamic Deformation, Damage and Fracture in Composite Materials and Structures

Dynamic Deformation, Damage and Fracture in Composite Materials and Structures PDF

Author: Vadim Silberschmidt

Publisher: Elsevier

Published: 2022-09-15

Total Pages: 666

ISBN-13: 0128239808

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Dynamic Deformation, Damage and Fracture in Composite Materials and Structures, Second Edition reviews various aspects of dynamic deformation, damage and fracture, mostly in composite laminates and sandwich structures, and in a broad range of application areas including aerospace, automotive, defense and sports engineering. This book examines low- and high-velocity loading and assesses shock, blast and penetrative events, and has been updated to cover important new developments such as the use of additive manufacturing to produce composites, including fiber-reinforced ones. New microstructural, experimental, theoretical, and numerical studies with advanced tools are included as well. The book also features four new chapters covering topics such as dynamic delamination, dynamic deformation and fracture in 3D-printed composites, ballistic impacts with fragmenting projectiles, and the effect of multiple impacting. Examines dynamic deformation and fracture of composite materials, covering experimental, analytical and numerical aspects Features four new chapters covering topics such as dynamic interfacial fracture, fracture in 3D-printed composites, ballistic impacts with fragmenting projectiles, and the effect of multiple impacting Addresses important application areas such as aerospace, automotive, wind energy, defense and sports

Impact Response and Dynamic Failure of Composites and Laminate Materials

Impact Response and Dynamic Failure of Composites and Laminate Materials PDF

Author: Jang Kyo Kim

Publisher: Trans Tech Publications Ltd

Published: 1997-09-04

Total Pages: 820

ISBN-13: 3035703671

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In many engineering applications of composite and laminate materials, damage and failure can be caused by impact of various types. Low-velocity impact is potentially dangerous because it can produce extensive sub-surface delamination that may not be visible on the surface. High-velocity impact produced by projectiles, shock waves and fragments from exploding ammunition is a highly dynamic event, leading to the penetration or perforation of composites. All impact damage is detrimental to the mechanical and structural performance of composites. Accurate evaluation of the damaged state, and a fundamental understanding of the effect of damage upon the resultant properties are therefore essential for the proper design and application of composite materials. The strain-rate dependence of material behavior, fracture propagation and energy-absorbing capacity are also of paramount importance from both the materials science and structural mechanics perspectives.

Copper and Bronze in Art

Copper and Bronze in Art PDF

Author: David A. Scott

Publisher: Getty Publications

Published: 2002

Total Pages: 536

ISBN-13: 9780892366385

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This is a review of 190 years of literature on copper and its alloys. It integrates information on pigments, corrosion and minerals, and discusses environmental conditions, conservation methods, ancient and historical technologies.

Dynamic Failure of Composite and Sandwich Structures

Dynamic Failure of Composite and Sandwich Structures PDF

Author: Serge Abrate

Publisher: Springer Science & Business Media

Published: 2012-11-02

Total Pages: 646

ISBN-13: 9400753292

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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.

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