Effects of Thermal Loading on Fiber-Reinforced Composites With Constituents of Differing Thermal Expansivities

1973 ◽  
Vol 95 (1) ◽  
pp. 55-62 ◽  
Author(s):  
C. A. Hoffman
Keyword(s):  
Thermal Loading ◽  
Volume Fraction ◽  
Fiber Composite ◽  
Large Strain ◽  
Experimental Studies ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Tungsten Fiber ◽  
Elastic Plastic ◽  
Elastic Stresses

Estimates of the magnitudes of elastic stresses and elastic-plastic stresses and strains were made for tungsten fiber-reinforced 80Ni + 20Cr matrix composites; heating or cooling between 80 and 2000 deg F (26.5–1093.5 deg C) was assumed. The calculated elastic stresses exceeded representative or estimated strengths of constituents. For composites with less than 0.65 volume fraction of fiber, plastic flow was considered possible, and elastic-plastic solutions indicated that stresses would be reduced but with the concomitant occurrence of sufficiently large strain ranges, particularly in the matrix, to pose a possible thermal fatigue problem. Limited experimental studies on tungsten fiber-copper matrix composites heated and cooled a number of times between 80 deg F (26.5 deg C) and 1600 deg F (877 deg C) in a conventional furnace and then heated from 80 deg F (26.5 deg C) to 1652 deg F (900 deg C) in a hot stage microscope resulted in matrix microfracture for a 70 volume fraction fiber composite and substantial matrix strain for a 40 volume fraction fiber composite.

Effects of Thermal Loading on Foil and Sheet Composites With Constituents of Differing Thermal Expansivities

1973 ◽  
Vol 95 (1) ◽  
pp. 47-54 ◽  
Author(s):  
C. A. Hoffman
Keyword(s):  
Structural Damage ◽  
Thermal Loading ◽  
Large Strain ◽  
Experimental Studies ◽  
Temperature Transition ◽  
Elastic Plastic ◽  
Elastic Stresses ◽  
Laminar Composites ◽  
Temperature Transition Rate ◽  
Thermal Expansivities

A study was made to estimate the magnitudes of elastic stresses and elastic-plastic stresses and strains in sheet or foil laminar composites. Using a model tungsten/80Ni + 20Cr laminar composite and assuming cooling or heating through a temperature range of 80–2000 deg F (26.5–1093.5 deg C), calculated elastic stresses exceeded published or estimated strengths of the constituents. Elastic-plastic stress-strain solutions resulted in lower estimated stress levels but with the concomitant occurrence of sufficiently large strain ranges to suggest possible thermal fatigue problems. Limited experimental studies using tungsten/80Ni + 20Cr foil and sheet laminar composites, slowly cycled between 80 and 2000 deg F (26.5–1093.5 deg C) or rapidly cycled between 80 and 1600 deg F (26.5–871 deg C) produced varying degrees of observable structural damage in from 1 to 11 cycles depending upon temperature transition rate and laminae thickness; these particular results might not occur with other combinations of materials.

An Elastic-Plastic Fracture Behavior of the Interface Using the Property Gradient in MMC

2005 ◽  
Vol 297-300 ◽  
pp. 148-153 ◽  
Author(s):  
Ji Woong Kang ◽  
Oh Heon Kwon
Keyword(s):  
Mechanical Response ◽  
Volume Fraction ◽  
High Strength ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Elastic Plastic ◽  
Fiber Arrangement ◽  
Hexagonal Arrangement ◽  
Transportation Applications

The strong continuous fiber reinforced metal matrix composites (MMCs) are recently used in aerospace and transportation applications as an advanced material due to its high strength and light weight. However, MMC is significantly affected by the interface under the transverse loading. Furthermore, the crack at the interface induces weakness of the characteristics of the overall mechanical response and strength of the MMCs. In order to be able to utilize these MMCs effectively and with safety, it must be determined their elastic plastic fracture behaviors at the interface. The influence of different regular fiber arrangement as like square and hexagonal arrangement on the strength of transversely loaded fiber reinforced matrix is analyzed. And the interface of fiber and matrix is modeled as thin multi layers with properties linearly gradient to distinguish the interface from the fiber and matrix. Different fiber arrangement of square and hexagon type is studied. And fiber volume fraction is changed for several kinds (5%-60%).

scholarly journals Multiscale thermomechanical modeling of short fiber-reinforced composites

2017 ◽  
Vol 24 (5) ◽  
pp. 765-772 ◽  
Author(s):  
Dawei Jia ◽  
Huiji Shi ◽  
Lei Cheng
Keyword(s):  
Thermal Loading ◽  
Volume Fraction ◽  
Numerical Procedure ◽  
Thermal Conditions ◽  
Cyclic Hardening ◽  
Short Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Thermomechanical Modeling

AbstractA study of the micromechanical behavior to predict the overall response of short fiber-reinforced composites under cyclic mechanical and thermal loading is presented. The instantaneous average over a “representative volume” of the material is considered. The influence of the short fiber’s aspect ratio, volume fraction, and spatial orientation has been investigated. The linear combined hardening model is used to describe the cyclic hardening effects in the case of metal matrix. A numerical procedure is used to predict the response of composites under mechanical and thermal conditions. The results of the numerical procedure have been compared to the results of three different models and to published experimental data.

Thermomechanical Behavior of Low CTE Metal-Matrix Composites Fabricated Through Ultrasonic Additive Manufacturing

2012 ◽  
Author(s):  
Ryan Hahnlen ◽  
Marcelo J. Dapino
Keyword(s):  
Shear Strength ◽  
Additive Manufacturing ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Large Strain ◽  
Matrix Composites ◽  
Interface Shear ◽  
Mechanical Coupling ◽  
Ultrasonic Additive Manufacturing

Shape memory and superelastic NiTi are often utilized for their large strain recovery and actuation properties. The objective of this research is to utilize the stresses generated by pre-strained NiTi as it is heated in order to tailor the CTE of metal-matrix composites. The composites studied consist of an Al 3003-H18 matrix with embedded NiTi ribbons fabricated through an emerging rapid prototyping process called Ultrasonic Additive Manufacturing (UAM). The thermally-induced strain of the composites is characterized and results show that the two key parameters in adjusting the effective CTE are the NiTi volume fraction and prestrain of the embedded NiTi. From the observed behavior, a constitutive composite model is developed based constitutive SMA models and strain matching composite models. Additional composites were fabricated to characterize the NiTi-Al interface through EDS and DSC. These methods were used to investigate the possibility of metallurgical bonding between the ribbon and matrix and determine interface shear strength. Interface investigation indicates that mechanical coupling is accomplished primarily through friction and the shear strength of the interface is 7.28 MPa. Finally, using the developed model, a composite was designed and fabricated to achieve a near zero CTE. The model suggests that the finished composite will have a zero CTE at a temperature of 135°C.

A Study on the Thermoelastic Analysis in Shear Deformable Discontinuous Composites

2004 ◽  
Vol 261-263 ◽  
pp. 645-650
Author(s):  
Hong Gun Kim
Keyword(s):  
Thermal Stresses ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Fiber Composite ◽  
Element Model ◽  
Short Fiber ◽  
Elastic Stresses ◽  
Fiber Aspect Ratio ◽  
The Matrix ◽  
Lag Model

A stress analysis has been performed to evaluate the thermally induced elastic stresses which can develop in a short fiber composite due to coefficient of thermal expansion (CTE) mismatch. An axisymmetric finite element model with the constraint between cells has implemented to find the magnitude of thermoelastic stresses in the fiber and the matrix as a function of volume fraction, CTE ratio, modulus ratio, and fiber aspect ratio. It was found that the matrix end regions fall under significant thermal stresses that have the same sign as that of the fibers themselves. Furthermore, it was found that the stresses vary along the fiber and fiber end gap in the same manner as that obtained in a shear-lag model during non-thermal mechanical loading.

Micromechanical theory and uniaxial tensile tests of fiber reinforced cement composites

1991 ◽  
Vol 6 (11) ◽  
pp. 2463-2473 ◽  
Author(s):  
C.C. Yang ◽  
T. Mura ◽  
S.P. Shah
Keyword(s):  
Volume Fraction ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Cement Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Theoretical Predictions ◽  
The Matrix ◽  
Reinforced Cement ◽  
Fracture Arrest

The mechanism of fracture arrest in brittle-matrix composites with strong, long fibers is analyzed by using the inclusion method. The maximum stress contribution of the matrix in composites is discussed in this paper. A critical volume fraction of fibers fc is theoretically derived. If the volume fraction f is less than fc, then debonding between fibers and matrix occurs before the crack propagates through the whole section. If f is greater than fc, then no debonding occurs before the crack propagates through the whole section. The value of fc depends on the matrix and fiber properties and the bond character of the interface. To verify the analytical predictions, experiments on fiber reinforced cement composites subjected to uniaxial tension were conducted. The results of the theoretical predictions were also compared satisfactorily with other published experimental data.

scholarly journals TENSILE TEST ANALYSIS OF NATURAL FIBER REINFORCED COMPOSITE

2014 ◽  
pp. 148-152
Author(s):  
G. VELMURUGAN ◽  
D. VADIVEL ◽  
R. ARRAVIND ◽  
A. MATHIAZHAGAN ◽  
S.P. VENGATESAN
Keyword(s):  
Natural Fiber ◽  
Volume Fraction ◽  
Fiber Composite ◽  
Tensile Load ◽  
Experimental Result ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Test Analysis ◽  
Reinforced Composite ◽  
Strain Stress

This project mainly deals with analysis of tensile properties of Palmyra fiber Reinforced Epoxy Composite that is suitable for automobile application. First, the property of material was obtained on the basis of some assumptions (i.e., Rule of Mixture) and was modeled with reference to ASTM D638. Here the simulation was carried out on specimen under different fiber volume fraction and fiber length. The present work includes the Analysis of Palmyra Fiber Reinforced Epoxy Composites using FEA with various fiber volume fractions and these results were validated with the experimental result. The tensile property of Palmyra fiber composite material can be obtained by using tensometer.During the tensile load, the maximum strain, stress and displacement were obtained and, then this experimental result was compared with the analytical results and the error percentage of these results were calculated.

scholarly journals Comparisons of thermomechanical fatigue hysteresis loops of fiber-reinforced ceramic-matrix composites subjected to different phase angles

2018 ◽  
Vol 233 (6) ◽  
pp. 2015-2032 ◽  
Author(s):  
Li Longbiao
Keyword(s):  
Volume Fraction ◽  
Frictional Coefficient ◽  
Hysteresis Loops ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Thermomechanical Fatigue ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Phase Angles

In this paper, comparisons of thermomechanical fatigue hysteresis loops of fiber-reinforced ceramic-matrix composites (CMCs) subjected to different phase angles of θ = 0, π/3, π/2, and π have been investigated. The shape, location, and area of fatigue hysteresis loops are affected by the phase angle under the thermomechanical cyclic loading. The effects of fiber volume fraction, fatigue peak stress, matrix crack spacing, interface frictional coefficient, and interface debonded energy on the thermomechanical fatigue hysteresis loops and fiber/matrix interface slip of different phase angles are discussed. The fatigue hysteresis loops of cross-ply CMCs under the phase angles of θ = 0 and π are predicted for different fatigue peak stresses and cycle numbers.

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