Analysis of Energy Dissipation in Twisted Fiber Bundles Under Cyclic Tensile Loading

2002 ◽  
Vol 72 (7) ◽  
pp. 585-593 ◽  
Author(s):  
Y. Qiu ◽  
Y. Wang ◽  
M. Laton ◽  
J.Z. Mi
Keyword(s):  
Energy Dissipation ◽  
Tensile Loading ◽  
Fiber Bundles ◽  
Twisted Fiber

Testing and Simulation of Stress-Stiffening Extreme Poisson’s Ratio Twisted Fiber-Reinforced Elastomer Composites

2008 ◽  
Author(s):  
Larry D. Peel ◽  
Madhuri Lingala
Keyword(s):  
Double Helix ◽  
Fiber Bundles ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Morphing Aircraft ◽  
Active Vibration ◽  
Elastomer Composites ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Twisted Fiber

Laminates that exhibit high and negative Poisson’s ratios can be used as solid-state actuators, passive and active vibration dampers, and for morphing aircraft structures. Recently, fiber-reinforced elastomer (FRE) laminates have been fabricated that exhibit extreme (high and negative) Poisson’s ratios [1]. The current research explores twisted fiber bundle elastomeric laminates (both single and double helix) which are being investigated using experimentation, linear and non-linear finite element analysis (FEA). Twisted fiber bundles can be made from carbon fibers, fiberglass, etc, but for simplicity the current work uses twisted cotton string. It is observed that uniaxial fiber-reinforced elastomer laminates, where the fibers are twisted as shown in Figure 1, exhibit stress stiffening. Negative Poisson’s ratios may be produced if the fiber bundles have a double helical path as simulated by a series of laminated tubes. Future auxetic FRE laminates may be developed that do experience extreme shear.

COMPUTATIONAL INVESTIGATION OF ENERGY DISSIPATION THROUGH PROGRESSIVE FAILURE IN TAILORED COMPOSITE STRUCTURES VIA EXPLICIT FINITE ELEMENT ANALYSIS

2021 ◽  
Author(s):  
ANIRUDH SRINIVAS ◽  
D. STEFAN DANCILA
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Material ◽  
Energy Dissipation ◽  
Progressive Failure ◽  
Tensile Loading ◽  
Stress Wave Propagation ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis

A composite material tailoring concept for progressive failure under tensile loading has been previously developed, modeled, and experimentally validated by the second author and his collaborators. The concept relies upon a sequential failure process induced in a structure of series connection of parallel redundant load path elements of tailored length and strength. The resulting yield-type response under tensile loading is characterized by an increased energy dissipation compared to a reference conventional structural element of nominally identical length and crosssectional area, and of the same composite material. In this work, this composite tailoring concept is computationally investigated for IM7-8552 composite material using a dynamic, explicit finite element analysis in Abaqus. The approach offers the advantage of capturing the stress wave propagation within the model throughout the dynamic failure sequence, thereby providing a better understanding of the failure progression and the energy dissipation mechanisms at work. In this study, progressive failure of the tailored composite structure is modeled and analyzed for different configurations of lengths and widths. Model predictions are illustrated for and compared with selected tailoring configurations from the literature. Developing an explicit finite element approach for analyzing the tailoring concept opens the door to characterizing a wide variety of related, more complex configurations for which analytical solutions do not yet exist or may not even be feasible, and/or for which experimental results may be difficult or overly expensive to obtain.

scholarly journals Mechanical Behavior of Red Sandstone under Incremental Uniaxial Cyclical Compressive and Tensile Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Baoyun Zhao ◽  
Dongyan Liu ◽  
Tianzhu Huang ◽  
Wei Huang ◽  
Wei Liu
Keyword(s):  
Energy Dissipation ◽  
Mechanical Behavior ◽  
Strain Curve ◽  
Tensile Loading ◽  
Creep Model ◽  
Short Term ◽  
Stress Strain ◽  
Cycle Number ◽  
Red Sandstone ◽  
Residual Strains

Uniaxial experiments were carried out on red sandstone specimens to investigate their short-term and creep mechanical behavior under incremental cyclic compressive and tensile loading. First, based on the results of short-term uniaxial incremental cyclic compressive and tensile loading experiments, deformation characteristics and energy dissipation were analyzed. The results show that the stress-strain curve of red sandstone has an obvious memory effect in the compressive and tensile loading stages. The strains at peak stresses and residual strains increase with the cycle number. Energy dissipation, defined as the area of the hysteresis loop in the stress-strain curves, increases nearly in a power function with the cycle number. Creep test of the red sandstone was also conducted. Results show that the creep curve under each compressive or tensile stress level can be divided into decay and steady stages, which cannot be described by the conventional Burgers model. Therefore, an improved Burgers creep model of rock material is constructed through viscoplastic mechanics, which agrees very well with the experimental results and can describe the creep behavior of red sandstone better than the Burgers creep model.

Assessment of Fracture Behavior of Flat Braided CFRP Composites Under Tensile Loading With Assistance of SQUID Technique

2011 ◽  
Author(s):  
Mohamed S. Aly-Hassan ◽  
Yuka Takai ◽  
Asami Nakai ◽  
Hiroyuki Hamada ◽  
Yohei Shinyama ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Pure Shear ◽  
Tensile Loading ◽  
Damage Mechanism ◽  
The State ◽  
Matrix Cracking ◽  
Fiber Bundles ◽  
Fiber Failure ◽  
Cfrp Composites

The goal of this research is to provide a sufficient understanding for the damage mechanism of ±45° flat braided CFRP composites under tensile loading based on in-situ macroscopic observations of surface cracking and off-line measurements for the state-of-fibers by Superconducting Quantum Interference Device (SQUID) technique to analyze the effect of the continuously oriented of all braided fiber bundles on the tensile and in-plane shear properties. SQUID technique displays an effective capability in inspection the state-of-fiber failure, whereas the in-situ surface macroscopic observation technique is very useful in observing the surface matrix cracking at different stages of damage. The damage mechanism of uncut-edges and cut-edges of ±45° flat braided CFRP composites are identified adequately by the above-mentioned experimental procedure. The cut-edges ±45° flat braided CFRP composites exhibit a pure shear damage mechanism associated with large shear deformation and no significant fiber failure, while the uncut-edges ±45° flat braided CFRP composites exhibit a slight fiber scissoring mechanism followed by a partially fiber failure. The enhancement of the tensile and in-plane strengths of the uncut-edges ±45° flat braided CFRP composites by about 60% higher than those of the cut-edges ±45° flat braided CFRP composites achieves not only by the effect of the continuously oriented carbon fibers at the edges but also by the effect of re-orientation of braiding fiber bundles with smaller angle than the original ±45° braiding angle of the fabricated composites, or so called fiber scissoring mechanism in composites.

Microstructure and Damage Evolution of Ceramic Matrix Composite

2006 ◽  
Vol 326-328 ◽  
pp. 1177-1180
Author(s):  
Wen Ge Pan ◽  
Gui Qiong Jiao ◽  
Bo Wang
Keyword(s):  
Energy Dissipation ◽  
Carbon Fiber ◽  
Damage Evolution ◽  
Ceramic Matrix Composite ◽  
Failure Stress ◽  
Fiber Bundles ◽  
Interface Debonding ◽  
Second Phase ◽  
The Third ◽  
Carbon Fiber Bundles

The tensile damage evolution of 2D plain woven C/SiC composites strengthened with 1K and 3K carbon fiber bundles and microstructure’s influence on material’s damage evolution were investigated using the Acoustic Emission technology (AE) and failure observation. Experimental results reveal that damage evolution of these two kinds of composites is a gradual procedure and this procedure consists of three phases. There is no damage during the first phase. During the second phase, the damage, mainly consisting of matrix microcrack cracking, interface debonding of fiber and joining of microcrack, random takes place in the whole area of specimen. During the third damage phase, the damage, mainly consisting of macrocrack cracking, fibers breaking and fibers pulling out, mainly takes place in the local failure area of specimen. Because the microstructures of composites with 1K and 3K carbon fiber bundles are different, their damage mechanisms are different. Composite strengthened with 1K carbon fiber bundles get in second phase at 90% failure stress, and their main energy dissipation occurred during the second damage phase. While Composite strengthened with 3K carbon fiber bundles get in second phase at 80% failure stress, and their main energy dissipation occurred during the third damage phase.

A Contrast Experimental Study of C40 Concrete Tensile Strength

2013 ◽  
Vol 815 ◽  
pp. 700-706
Author(s):  
Ping Li ◽  
Yong Chi Li ◽  
Shi Wei Duan ◽  
Rui Yuan Huang
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Hydrostatic Pressure ◽  
Energy Dissipation ◽  
Tensile Loading ◽  
Comprehensive Analysis ◽  
Loading Device ◽  
Tensile Experiment ◽  
Direct Tensile ◽  
The Comparative Study

In order to obtain the tensile strength of the C40 concrete accurately, the comparative study between Brazilian disc splitting experiment and the direct tensile experiment is conducted with a self-modified tensile loading device. The study shows that the tensile strength observed from the direct tensile experiments (3.64MPa) is lower than that from the experiments (5.44MPa). A comprehensive analysis of experimental results is conducted focusing on the perspectives of the specimen failure forms, energy dissipation, the correlation of strength and hydrostatic pressure etc. The study suggests that the main reasons for the differences between Brazilian tensile experimental strength and direct tensile experimental strength include the surface energy required by the specimen destruction, the bond strength between the aggregate, the hydrostatic pressure in the process of loading and other factors.

Sem Examinations of Glass Knives

1970 ◽  
Vol 28 ◽  
pp. 282-283
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Tensile Loading ◽  
Resultant Force ◽  
Stress Concentrations ◽  
Edge Chipping ◽  
Surface Flaws ◽  
Edge Defects ◽  
Microscopic Surface

There are two types of edge defects common to glass knives as typically prepared for microtomy purposes: 1) striations and 2) edge chipping. The former is a function of the free breaking process while edge chipping results from usage or bumping of the edge. Because glass has no well defined planes in its structure, it should be highly resistant to plastic deformation of any sort, including tensile loading. In practice, prevention of microscopic surface flaws is impossible. The surface flaws produce stress concentrations so that tensile strengths in glass are typically 10-20 kpsi and vary only slightly with composition. If glass can be kept in compression, wherein failure is literally unknown (1), it will remain intact for long periods of time. Forces acting on the tool in microtomy produce a resultant force that acts to keep the edge in compression.

Dupuytren's Contracture and Microvessels

1981 ◽  
Vol 39 ◽  
pp. 470-471
Author(s):  
C. W. Klscher ◽  
D. Speer
Keyword(s):  
Hypertrophic Scar ◽  
Active Form ◽  
Scar Tissue ◽  
Vascular Supply ◽  
Fiber Bundles ◽  
Dupuytren’S Contracture ◽  
Palmar Fascia ◽  
Immune Disease ◽  
Dupuytren's Contracture ◽  
Longitudinal Fiber

Dupuytren's Contracture is a nodular proliferation of the longitudinal fiber bundles of palmar fascia with its attendant contraction. The factors attributed to its etiology have included trauma, diabetes, alcoholism, arthritis, and auto-immune disease. The tissue has been observed by electron microscopy and found to contain myofibroblasts.Dupuytren's Contracture constitutes a scar, and as such, excessive collagen can be observed, along with an active form of fibroblast.Previous studies of the hypertrophic scar have led us to propose that integral in the initiation and sustenance of scar tissue is a profusion of microvascular regeneration, much of which becomes and remains occluded producing a hypoxia which stimulates fibroblast synthesis. Thus, when considering a study of Dupuytren's Contracture, we predicted finding occluded microvessels at or near the fascial scarring focus.Three cases of Dupuytren's Contracture yielded similar specimens, which were fixed in Karnovskys fluid for 2 to 20 days. Upon removal of the contracture bands care was taken to include the contiguous fatty and areolar tissue which contain the vascular supply and to identify the junctional area between old and new fascia.

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