Propagation of three-dimensional shear waves in orthotropic laminated composites

1982 ◽  
Vol 18 (1) ◽  
pp. 118-122
Author(s):  
V. M. Antonenko ◽  
A. N. Podlipenets ◽  
N. A. Shul'ga
Keyword(s):  
Laminated Composites ◽  
Shear Waves ◽  
Three Dimensional

Shear waves in a nonlinear relaxing media: A three-dimensional perspective

2021 ◽  
Vol 149 (3) ◽  
pp. 1589-1595
Author(s):  
Giuseppe Saccomandi ◽  
Maurizio S. Vianello
Keyword(s):  
Shear Waves ◽  
Three Dimensional

scholarly journals Impact Resistance Study of Three-Dimensional Orthogonal Carbon Fibers/BMI Resin Woven Composites

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4376
Author(s):  
Yanqi Hu ◽  
Zekan He ◽  
Haijun Xuan
Keyword(s):  
Carbon Fibers ◽  
High Efficiency ◽  
Laminated Composites ◽  
Impact Resistance ◽  
Three Dimensional ◽  
High Strength ◽  
Woven Composites ◽  
Failure Behavior ◽  
Bismaleimide Resin ◽  
Modeling Strategy

Three-dimensional woven composites have been reported to have superior fracture toughness, fatigue life and damage tolerance compared with laminated composites due to through-thickness reinforcement. These properties make them lighter replacements for traditional high-strength metals and laminated composites. This paper will present impact resistance research on three-dimensional orthogonal woven composites consisting of carbon fibers/bismaleimide resin (BMI). A series of impact tests were conducted using the gas gun technique with the impacted target of 150 mm × 150 mm × 8 mm (length × width × thickness) and the cylindrical titanium projectile. The projectile velocity ranged from 180 m/s to 280 m/s, generating different results from rebound to perforation. This paper also presents a multiscale modeling strategy to investigate the damage and failure behavior of three-dimensional woven composites. The microscale and mesoscale are identified to consider the fiber/matrix scale and the tow architecture scale respectively. The macroscale model was effective with homogenized feature. Then a combined meso-macroscale model was developed with the interface definitions for component analysis in the explicit dynamic software LS-DYNA. The presented results showed reliable interface connection and can be used to study localized composites damage at a relatively high efficiency.

Mechanical Behavior of Laminated Composites with Circular Holes

2013 ◽  
Vol 550 ◽  
pp. 1-8 ◽  
Author(s):  
Habib Achache ◽  
Benali Boutabout ◽  
Djamel Ouinas
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Composite Structures ◽  
Laminated Composites ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Element Formulation ◽  
Composites Materials ◽  
Circular Holes ◽  
Fibers Orientation

This paper presents a numerical method for the evaluation of the stress concentration factor (SCF) in three dimensional laminated composites under mechanical loads. The proposed method uses the finite element formulation. The composites materials based on the epoxy matrix and reinforcing fibers are extensively used in aircraft structures due to their high specific characteristics. However, the withstanding of composite structures can be significantly reduced by the addition of geometric singularities, such as perforations or notches. To Analyses the stress concentration around geometrical notches, several studies as analytical, numerical and experimental techniques are available. The stress distribution in a laminated composite plate with the presence of a circular hole was investigated using the finite element method. In order, the results obtained by this study are compared with those reported in literature. The aim of this analysis is to evaluate numerically the factor of stress concentration under the influence of several parameters such as fibers orientation, the mechanical characteristics of composites and the distance between notches of cross-laminated.

THREE‐DIMENSIONAL SEISMIC MODEL STUDIES

Geophysics ◽  
1955 ◽  
Vol 20 (1) ◽  
pp. 19-32 ◽  
Author(s):  
F. K. Levin ◽  
H. C. Hibbard
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Elastic Wave ◽  
Surface Waves ◽  
Shear Waves ◽  
Three Dimensional ◽  
Seismic Model ◽  
Model Studies ◽  
Ground Roll ◽  
Detector Configurations

Elastic wave propagation in a two‐layer section has been studied with a solid two‐bed model and records resembling seismograms obtained for the four possible source‐detector configurations. Numerous events are identified. Among these, the shear waves are found to be surprisingly prominent. The amplitude of the ground roll falls off approximately as [Formula: see text] This is the amplitude‐range dependence expected for a surface wave. The ability of two in‐line detectors to reduce surface waves has been demonstrated.

Three-Dimensional Effective Moduli of Orthotropic and Symmetric Laminates

1992 ◽  
Vol 59 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Ajit K. Roy ◽  
Stephen W. Tsai
Keyword(s):  
Laminated Composites ◽  
Three Dimensional ◽  
Shear Stiffness ◽  
Accurate Method ◽  
Homogeneous System ◽  
Solution Technique ◽  
Stacking Sequence ◽  
Effective Moduli ◽  
Function Solution ◽  
Interlaminar Shear

A simple and accurate method for estimating the three-dimensional effective moduli of symmetric and orthotropic laminated composites is presented. The method is based on obtaining the exact displacement field of three boundary value problems of laminated composites using the Airy stress function solution technique. The effective moduli are estimated by matching the boundary displacements of the equivalent homogeneous system with those of the laminated system. Among the estimated effective moduli, those associated with the interlaminar direction are of special interest. It is found that the effective interlaminar normal stiffness in extensional deformation is independent of laminae stacking sequence which is consistent with the finding of Pagano (1974). However, the laminate interlaminar shear stiffness is dependent on stacking sequence, and it is shown that the rule of mixtures can not predict the interlaminar shear stiffness accurately.

scholarly journals Anti-plane shear waves in periodic elastic composites: band structure and anomalous wave refraction

2015 ◽  
Vol 471 (2180) ◽  
pp. 20150152 ◽  
Author(s):  
Sia Nemat-Nasser
Keyword(s):  
Band Structure ◽  
Phase Velocity ◽  
Negative Refraction ◽  
Mass Density ◽  
Shear Waves ◽  
Variable Mass ◽  
Three Dimensional ◽  
Positive Energy ◽  
Plane Shear ◽  
Elastic Composites

For anti-plane shear waves in periodic elastic composites, it is shown that negative energy refraction can be accompanied by positive phase-velocity refraction and positive energy refraction can be accompanied by negative phase-velocity refraction , and that this can happen over a broad range of frequencies. Hence, in general, negative refraction does not necessarily require antiparallel group and phase-velocity vectors. Details are given for layered composites and the results are extended to, and illustrated for, two-dimensional periodic composites, revealing a wealth of information about the refractive characteristics of this class of composites. The composite's unit cell may consist of any number of constituents of any variable mass density and elastic modulus, admitting large discontinuities . A powerful variational-based solution method is used that applies to one-, two- and three-dimensional composites, irrespective of their constituents being homogeneous or heterogeneous. The calculations are direct, accurate and efficient, yielding the band structure, group-velocity, energy-flux and phase-velocity vectors as functions of the frequency and wavevector components, over an entire frequency band.

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