Polarization approximations for the macroscopic elastic constants of transversely isotropic multicomponent unidirectional fiber composites

2015 ◽  
Vol 49 (30) ◽  
pp. 3765-3780 ◽  
Author(s):  
AB Tran ◽  
DC Pham
Keyword(s):  
Elastic Constants ◽  
Transversely Isotropic ◽  
Fiber Composites ◽  
Unidirectional Fiber

Failure Criteria for Unidirectional Fiber Composites

1980 ◽  
Vol 47 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Z. Hashin
Keyword(s):  
Stress State ◽  
Failure Modes ◽  
Three Dimensional ◽  
Transversely Isotropic ◽  
Failure Surface ◽  
Failure Criteria ◽  
Fiber Composites ◽  
Piecewise Smooth ◽  
Average Stress ◽  
Unidirectional Fiber

Three-dimensional failure criteria of unidirectional fiber composites are established in terms of quadratic stress polynomials which are expressed in terms of the transversely isotropic invariants of the applied average stress state. Four distinct failure modes—tensile and compressive fiber and matrix modes—are modeled separately, resulting in a piecewise smooth failure surface.

Fatigue Failure Criteria for Unidirectional Fiber Composites

1981 ◽  
Vol 48 (4) ◽  
pp. 846-852 ◽  
Author(s):  
Z. Hashin
Keyword(s):  
Fatigue Failure ◽  
Failure Modes ◽  
Three Dimensional ◽  
Transversely Isotropic ◽  
Failure Criteria ◽  
Fiber Composites ◽  
Cyclic Stress ◽  
Unidirectional Fiber ◽  
Single Stress ◽  
Material Information

Three-dimensional fatigue failure criteria for unidirectional fiber composites under states of cyclic stress are established in terms of quadratic stress polynomials which are expressed in terms of the transversely isotropic invariants of the cyclic stress. Two distinct fatigue failure modes, fiber mode, and matrix mode, are modeled separately. Material information needed for the failure criteria are the S-N curves for single stress components. A preliminary approach to incorporate scatter into the failure criteria is presented.

scholarly journals Stochastic nonlinear analysis of unidirectional fiber composites using image-based microstructural uncertainty quantification

2021 ◽  
Vol 260 ◽  
pp. 113470
Author(s):  
Tianyu Huang ◽  
Jiaying Gao ◽  
Qingping Sun ◽  
Danielle Zeng ◽  
Xuming Su ◽  
...  
Keyword(s):  
Uncertainty Quantification ◽  
Nonlinear Analysis ◽  
Fiber Composites ◽  
Unidirectional Fiber

The Elastic Characterization of Composite Based on Ultrasonic Waves

2021 ◽  
Author(s):  
Y. H. Park ◽  
J. Dana
Keyword(s):  
Composite Materials ◽  
Fatigue Failure ◽  
Elastic Constants ◽  
Material Properties ◽  
Weight Ratio ◽  
Transversely Isotropic ◽  
Ultrasonic Waves ◽  
Material Strength ◽  
Isotropic Composite

Abstract Anisotropic composite materials have been extensively utilized in mechanical, automotive, aerospace and other engineering areas due to high strength-to-weight ratio, superb corrosion resistance, and exceptional thermal performance. As the use of composite materials increases, determination of material properties, mechanical analysis and failure of the structure become important for the design of composite structure. In particular, the fatigue failure is important to ensure that structures can survive in harsh environmental conditions. Despite technical advances, fatigue failure and the monitoring and prediction of component life remain major problems. In general, cyclic loadings cause the accumulation of micro-damage in the structure and material properties degrade as the number of loading cycles increases. Repeated subfailure loading cycles cause eventual fatigue failure as the material strength and stiffness fall below the applied stress level. Hence, the stiffness degradation measurement can be a good indication for damage evaluation. The elastic characterization of composite material using mechanical testing, however, is complex, destructive, and not all the elastic constants can be determined. In this work, an in-situ method to non-destructively determine the elastic constants will be studied based on the time of flight measurement of ultrasonic waves. This method will be validated on an isotropic metal sheet and a transversely isotropic composite plate.

scholarly journals Minimum energy bounds on longitudinal elastic constants of transversely isotropic unidirectional composites

2020 ◽  
Vol 476 (2239) ◽  
pp. 20190752
Author(s):  
Duc-Chinh pham
Keyword(s):  
Elastic Constants ◽  
Minimum Energy ◽  
Young Modulus ◽  
Transversely Isotropic ◽  
Longitudinal Axis ◽  
Arithmetic Average ◽  
Energy Bounds ◽  
Cylindrical Phase ◽  
Elastic Composites ◽  
Energy Principles

We consider the n -component transversely isotropic unidirectional elastic composites, the longitudinal axis of which is parallel to those of the transversely isotropic components as well as the generators of the cylindrical phase boundaries between them. From the minimum energy and complementary energy principles, with appropriate constant strain and piece-wise constant stress trial fields, optimization and iteration techniques, a set of bounds for the macroscopic (effective) longitudinal elastic constants of the composites (including the simple lower arithmetic average estimate for longitudinal Young modulus E eff  ≥  E V ) are constructed. Numerical examples are provided to illustrate the obtained results.

Do traveltimes in pulse‐transmission experiments yield anisotropic group or phase velocities?

Geophysics ◽  
1994 ◽  
Vol 59 (11) ◽  
pp. 1774-1779 ◽  
Author(s):  
Joe Dellinger ◽  
Lev Vernik
Keyword(s):  
Phase Velocity ◽  
Group Velocity ◽  
Elastic Constants ◽  
Near Field ◽  
Frequency Dispersion ◽  
Transversely Isotropic ◽  
Sh Waves ◽  
Phase Velocities ◽  
Pulse Transmission ◽  
Transmission Technique

The elastic properties of layered rocks are often measured using the pulse through‐transmission technique on sets of cylindrical cores cut at angles of 0, 90, and 45 degrees to the layering normal (e.g., Vernik and Nur, 1992; Lo et al., 1986; Jones and Wang, 1981). In this method transducers are attached to the flat ends of the three cores (see Figure 1), the first‐break traveltimes of P, SV, and SH‐waves down the axes are measured, and a set of transversely isotropic elastic constants are fit to the results. The usual assumption is that frequency dispersion, boundary reflections, and near‐field effects can all be safely ignored, and that the traveltimes measure either vertical anisotropic group velocity (if the transducers are very small compared to their separation) or phase velocity (if the transducers are relatively wide compared to their separation) (Auld, 1973).

Elastic Constants of Composite Materials by an Inverse Determination Method Based on A Hybrid Genetic Algorithm

2010 ◽  
Vol 26 (3) ◽  
pp. 345-353 ◽  
Author(s):  
S.-F. Hwang ◽  
J.-C. Wu ◽  
Evgeny Barkanovs ◽  
Rimantas Belevicius
Keyword(s):  
Genetic Algorithm ◽  
Elastic Constants ◽  
Hybrid Genetic Algorithm ◽  
Transversely Isotropic ◽  
Determination Method ◽  
Element Analysis ◽  
Plane Shear ◽  
Effective Elastic Constants ◽  
Testing Data ◽  
Out Of Plane

AbstractA numerical method combining finite element analysis and a hybrid genetic algorithm is proposed to inversely determine the elastic constants from the vibration testing data. As verified from composite material specimens, the repeatability and accuracy of the proposed inverse determination method are confirmed, and it also proves that the concept of effective elastic constants is workable. Moreover, three different sets of assumptions to reduce the five independent elastic constants to four do not make clear difference on the obtained results by the proposed method. In addition, to obtain robust values of the five elastic constants for a transversely isotropic material, it is recommended to use the out-of-plane Poisson's ratio instead of the out-of-plane shear modulus as the fifth one.

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