scholarly journals Prediction of Matrix Failure in Fibre Reinforced Polymer Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
J. Wang ◽  
W. K. Chiu
Keyword(s):  
Prediction Accuracy ◽  
Pure Shear ◽  
Matrix Material ◽  
Tensile Load ◽  
Fem Analysis ◽  
Failure Criteria ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Load Case ◽  
Surrounding Matrix

Recent development has enabled fibre and matrix failure in a fibre reinforced composite material to be predicted separately. Matrix yield/failure prediction is based on a Von Mises strain and first strain invariant criteria. Alternative matrix failure criteria for enhanced prediction accuracy are discussed in this paper. The proposed failure envelope formed with basic failure criteria intersects with uniaxial compression, pure shear and uniaxial tensile test data points smoothly. For failure of typical neat resin, significant improvement of prediction accuracy compared with measured material data is demonstrated. For a unit cell with a fibre and surrounding matrix with typical material properties, a FEM analysis indicates a significant improvement in prediction accuracy in the pure shear load case and a marginal improvement in the biaxial tensile load case. This paper also provided a preliminary discussion about the issues when material nonlinearity of the matrix material is involved.

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

Bond investigation of hybrid textile with self-compacting fine-grain concrete

2016 ◽  
Vol 46 (8) ◽  
pp. 1616-1632 ◽  
Author(s):  
Shiping Yin ◽  
Bo Wang ◽  
Fei Wang ◽  
Shilang Xu
Keyword(s):  
Tensile Load ◽  
Experimental Results ◽  
Interfacial Property ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Multiple Cracks ◽  
Textile Reinforced Concrete ◽  
Fine Grain ◽  
Resin Impregnation ◽  
Relationship Of

This paper presents an experimental investigation into the influence of bond characteristics between textile and matrix on the mechanical behavior of textile-reinforced concrete (TRC). Two types of tests were performed, i.e. pullout test and uniaxial tensile test. Self-compacting fine-grain concrete was adopted. Two kinds of hybrid textile, consisting of both carbon and E-glass yarns, were specially prepared for this study. The experimental results show that sticking sands on the textile after epoxy resin impregnation can improve the interfacial property between textile and matrix. The specimens with textile of 10 mm × 10 mm mesh have stronger bond strength than those with textile of 25 mm × 25 mm mesh, and can reach the maximum tensile strength of yarns when the initial bond length is between 30 mm and 35 mm. Moreover, sticking sands on the textile can improve the multiple cracks form and the ultimate bearing capacity of TRC under uniaxial tensile load. Specimens with textile of 10 mm × 10 mm mesh have higher first-crack loads than those with textile of 25 mm × 25 mm mesh whether or not the textile surface treatment was conducted, and also have better crack distribution. Finally, based on the experimental results from TRC under uniaxial tensile load, a double linear constitutive equation of stress–strain relationship of carbon fiber yarn is provided in this paper.

Fully-Modeled Unit Cell Analysis for Macro/Micro Elastic-Viscoplastic Behavior of Quasi-Isotropic CFRP Laminates

2014 ◽  
Vol 626 ◽  
pp. 512-517 ◽  
Author(s):  
Keita Goto ◽  
Tetsuya Matsuda ◽  
Naoto Kubota
Keyword(s):  
Carbon Fiber ◽  
Matrix Material ◽  
Tensile Load ◽  
Unit Cell ◽  
Homogenization Theory ◽  
Uniaxial Tensile ◽  
Hexagonal Prism ◽  
Cell Analysis ◽  
Cfrp Laminate ◽  
Isotropic Carbon

A fully-modeled unit cell analysis is performed to investigate the macroscopic and microscopic elastic-viscoplastic behaviors of a quasi-isotropic carbon fiber-reinforced plastic (CFRP) laminate. To this end, a quasi-isotropic CFRP laminate and its microstructure composed of carbon fibers and a matrix material are considered three-dimensionally. Then, a hexagonal prism-shaped unit cell fully modeled with fibers and a matrix including interlaminar areas is defined. For this quasi-isotropic laminate, a homogenization theory for nonlinear time-dependent composites with point-symmetric internal structures is applied, enabling us to analyze both the macroscopic and microscopic elastic-viscoplastic behaviors of the laminate. The substructure method is introduced into the theory to reduce computational costs. The present method is then applied to the elastic-viscoplastic analysis of a quasi-isotropic carbon fiber/epoxy laminate subjected to an in-plane uniaxial tensile load, to investigate the macroscopic elastic-viscoplastic behavior of the laminate and the microscopic stress and strain distributions in them.

Modeling and Experimental Validation of Composite Stiffened Panels under Uniaxial Tension

2013 ◽  
Vol 791-793 ◽  
pp. 415-418
Author(s):  
Hong Qing Wang ◽  
Qun Yan ◽  
Zong Hong Xie ◽  
Xiao Dong Sui
Keyword(s):  
Finite Element ◽  
Uniaxial Tension ◽  
Tensile Load ◽  
Element Model ◽  
Failure Criteria ◽  
Uniaxial Tensile ◽  
Stiffened Panel ◽  
Propagation Mechanism ◽  
Cohesive Elements ◽  
Composite Stiffened Panel

A finite element model implemented with a progressive damage propagation mechanism was generated to study the mechanical behavior of stiffened composite panels under uniaxial tension. Typical damage modes including fiber breakage, matrix crushing and delamination were considered in the model. Failure criteria with corresponding stiffness degradation technologies was used to predict the initiation and evolution of intra-laminar damage modes by a user-defined subroutine. Cohesive elements with thickness of 0.01mm were defined along the interface areas between the filler and the adjacent laminate layers for predicting the initiation and propagation of delamination. Corresponding tests on composite stiffened panel with a web cut-out were conducted. A good correlation between the numerical results and test data was obtained, which validated the finite element models. Both the numerical and experimental results conclude that the delamination in the flange around the cut-out region is the most critical failure mode for the composite stiffened panel under the uniaxial tensile load.

scholarly journals A Proposed Methodology for Strain-Based Failure Criteria

2008 ◽  
Author(s):  
Tsu-Te Wu
Keyword(s):  
Failure Criteria ◽  
Radioactive Material ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Dynamic Simulations ◽  
Tensile Test Specimen ◽  
Asme Code ◽  
Hypothetical Accident ◽  
Material Fracture ◽  
Accident Conditions

This paper proposes an alternative methodology to determine the failure criteria for use in dynamic simulations of radioactive material shipping packages in the events of hypothetical accident conditions. The current stress failure criteria defined in the Nuclear Regulatory Guide 7.6 [1] and the ASME Code, Section III, Appendix F [2] for Level D Service Loads are based on the ultimate strength of uniaxial tensile test specimen rather than on the material fracture in the state of multi-axial stresses. On the other hand, the proposed strain-based failure criteria are directly related to the material failure mechanisms in multi-axial stresses. In addition, unlike the stress-based criteria, the strain-based failure criteria are applicable to the evaluation of cumulative damages caused by the sequential loads in the hypothetical accident events as required by the Nuclear Regulatory Guide 7.8 [4].

Failure Criteria for Some Polyurethane Propellants

1964 ◽  
Vol 37 (2) ◽  
pp. 511-523 ◽  
Author(s):  
Warren T. Milloway ◽  
James H. Wiegand
Keyword(s):  
Failure Criteria ◽  
Shift Factor ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Theoretical Studies ◽  
Hoop Strain ◽  
Breaking Strain ◽  
Uniaxial Test ◽  
Lower Variability ◽  
Experimental And Theoretical Studies

Abstract Experimental and theoretical studies were made on failure criteria applicable to simple case-bonded hollow cylindrical grains. The minimum strain at break at −75° F for uniaxial tensile test was found to be at least twice the hoop strain at −75° F of a thermally cycled, case-bonded hollow cylinder of propellant when no failures were observed, whereas, when the minimum strain at break was equal to or less than the hoop strain of the cycled cylinder, the grain always cracked. For uniaxial tension, where the rate of elongation and temperature are controlled variables, the failure elongation varies from specimen to specimen and from batch to batch. A study of batch variability of the uniaxial test showed that a test at any test temperature from −40° to 180° F could be used to characterize batch quality. The correlation of breaking strain at different rates and temperatures with the use of the WLF technique on one batch was found to be improved if an additional vertical shift factor was added to account for the lowering of the maximum failure elongation for temperatures below 0° F. However, by using a diagonal shift with rate, a graph of failure elongation versus temperature shows lower variability than does the WLF analysis.

A new pseudo-energy function to simulate the Mullins effect

2017 ◽  
Vol 50 (6) ◽  
pp. 554-575
Author(s):  
Eduardo Guilherme Mötke Wrubleski ◽  
Rogério Marczak
Keyword(s):  
Experimental Data ◽  
Pure Shear ◽  
Constitutive Models ◽  
Constitutive Law ◽  
Hyperelastic Material ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Mullins Effect ◽  
Softening Effect ◽  
Material Models

Several authors have proposed different parameters to include the softening effect in hyperelastic models; however, for a number of materials, softening parameters could be further improved. This article proposes a new softening parameter to include Mullins effect in hyperelastic material models. The methodology employed can be also used in cases with hysteresis or damage in a hyperelastic material, however this methodology modifies the behavior of the material differently from damage theories. Common hyperelastic constitutive models do not include dissipation effects and so the present work intends to fill this gap. Experimental data for silicone in uniaxial tensile test, equibiaxial, and pure shear tests were modeled in order to calibrate the models. The softening parameters essentially changes the constitutive law from the loading to the unloading path. Therefore, it is still necessary to use a hyperelastic model, and here Ogden and Hoss-Marczak material models were used. The obtained results show good agreement with experimental data even when simulating with a compressible finite element code and it can model isotropic Mullins effect.

scholarly journals Biomechanical-Structural Correlation of Chordae tendineae in Animal Models: A Pilot Study

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1678
Author(s):  
Justyn Gach ◽  
Izabela Janus ◽  
Agnieszka Mackiewicz ◽  
Tomasz Klekiel ◽  
Agnieszka Noszczyk-Nowak
Keyword(s):  
Mitral Valve ◽  
Complex Structure ◽  
Future Research ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Histopathological Analysis ◽  
Papillary Muscles ◽  
Chordae Tendineae ◽  
Structural Correlation ◽  
Ring Valve

The mitral valve apparatus is a complex structure consisting of the mitral ring, valve leaflets, papillary muscles and chordae tendineae (CT). The latter are mainly responsible for the mechanical functions of the valve. Our study included investigations of the biomechanical and structural properties of CT collected from canine and porcine hearts, as there are no studies about these properties of canine CT. We performed a static uniaxial tensile test on CT samples and a histopathological analysis in order to examine their microstructure. The results were analyzed to clarify whether the changes in mechanical persistence of chordae tendineae are combined with the alterations in their structure. This study offers clinical insight for future research, allowing for an understanding of the process of chordae tendineae rupture that happens during degenerative mitral valve disease—the most common heart disease in dogs.

scholarly journals Experimental and Numerical Evaluation of Mechanical Properties of 3D-Printed Stainless Steel 316L Lattice Structures

2021 ◽  
Author(s):  
M. Carraturo ◽  
G. Alaimo ◽  
S. Marconi ◽  
E. Negrello ◽  
E. Sgambitterra ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Mechanical Behavior ◽  
Numerical Simulations ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Lattice Structures ◽  
Stainless Steel 316L ◽  
Research Attention ◽  
Octet Truss

AbstractAdditive manufacturing (AM), and in particular selective laser melting (SLM) technology, allows to produce structural components made of lattice structures. These kinds of structures have received a lot of research attention over recent years due to their capacity to generate easy-to-manufacture and lightweight components with enhanced mechanical properties. Despite a large amount of work available in the literature, the prediction of the mechanical behavior of lattice structures is still an open issue for researchers. Numerical simulations can help to better understand the mechanical behavior of such a kind of structure without undergoing long and expensive experimental campaigns. In this work, we compare numerical and experimental results of a uniaxial tensile test for stainless steel 316L octet-truss lattice specimen. Numerical simulations are based on both the nominal as-designed geometry and the as-build geometry obtained through the analysis of µ-CT images. We find that the use of the as-build geometry is fundamental for an accurate prediction of the mechanical behavior of lattice structures.

scholarly journals Polar poly(n-butyl acrylate)-g-polyacrylonitrile elastomer with high temperature elasticity and healability as flexible electronic substrate

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuzhu Zheng ◽  
Deli Xu ◽  
Shiyou Tian ◽  
Manli Li ◽  
Wenwen Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Graft Copolymer ◽  
Butyl Acrylate ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Self Healing ◽  
Chemical Structures ◽  
Flexible Electronic ◽  
Ag Nanowires ◽  
Cyano Groups

AbstractIn this work, graft copolymer poly (n-butyl acrylate)-g-polyacrylonitrile with poly (n-butyl acrylate) as backbones and polyacrylonitrile as side chains (PnBA-g-PAN) was synthesized by macromonomer method and emulsion polymerization. The macromonomer was synthesized by atom transfer radical polymerization and end-group modification. The chemical structures and thermal properties of macromonomer and graft copolymer were investigated by FTIR, GPC, NMR and TGA, etc. The mechanical properties of graft copolymer elastomer was also measured by uniaxial tensile test. Rheological properties at different temperature and mechanical property demonstrated that graft copolymer elastomer possessed elasticity until 180 oC because of cyclization of cyano groups. Ag nanowires@PnBA-g-PAN composite elastomer was developed, and the resulted material exhibited autonomic healing property on account of segments’ flexibility and dynamic interaction between Ag nanowires (AgNWs) and cyano groups. This is a general method for generation of elastomer with high temperature elasticity and fast self-healing. The composite elastomer has potential application in flexible electronic conductor.

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