Evaluation of in-plane shear modulus of composite laminates using holographic interferometry

1997 ◽  
Vol 36 (7) ◽  
pp. 1942 ◽  
Author(s):  
Takenori Maeda
Keyword(s):  
Shear Modulus ◽  
Holographic Interferometry ◽  
Composite Laminates ◽  
Plane Shear

Features of nonlinear in-plane shear deformation of a unidirectional and orthogonally reinforced polymer sheets of composite materials

2021 ◽  
Vol 87 (5) ◽  
pp. 47-55
Author(s):  
A. O. Polovyi ◽  
N. V. Matiushevski ◽  
N. G. Lisachenko
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Shear Modulus ◽  
Maximum Deviation ◽  
Linear Section ◽  
Stress Strain ◽  
Plane Shear ◽  
End Point ◽  
Reinforced Polymer ◽  
Failure Point

A comparative analysis of typical stress-strain diagrams obtained for in-plain shear of the 25 unidirectional and cross-ply reinforced polymer matrix composites under quasi-static loading was carried out. Three of them were tested in the framework of this study, and the experimental data on other materials were taken from the literature. The analysis of the generalized shear-strength curves showed that most of the tested materials exhibit the similar deformation pattern depending on their initial shear modulus: a linear section is observed at the beginning of loading, whereas further increase of the load decreases the slope of the curve reaching the minimum in the failure point. For the three parameters (end point the linear part, maximum reduced deviation of the diagram, tangent shear modulus at the failure point) characterizing the individual features of the presented stress-strain diagrams, approximating their dependences on the value of the reduced initial shear modulus are obtained. At the characteristic points of the deformation diagrams, boundary conditions are determined that can be used to find the parameters of the approximating functions. A condition is proposed for determination of the end point of the linear section on the experimental stress-strain curve, according to which the maximum deviation between the experimental and calculated (according to Hooke’s law) values of the shear stress in this section is no more than 1%, thus ensuring rather high accuracy of approximation on the linear section of the diagram. The results of this study are recommended to use when developing universal and relatively simple in structure approximating functions that take into account the characteristic properties of the experimental curves of deformation of polymer composite materials under in-plane shear of the sheet. The minimum set of experimental data is required to determine the parameters of these functions.

Hybrid composite laminates reinforced with flax-basalt-glass woven fabrics for lightweight load bearing structures

2020 ◽  
pp. 152808372096074
Author(s):  
Mohamed A Attia ◽  
Marwa A Abd El-baky ◽  
Mostafa M Abdelhaleem ◽  
Mohamed A Hassan
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Failure Modes ◽  
Woven Fabrics ◽  
Plane Shear ◽  
Load Bearing ◽  
Impact Properties ◽  
Basalt Glass ◽  
Interlaminar Shear ◽  
The Impact

An experimental investigation on the mechanical performance of interlayer hybrid flax-basalt-glass woven fabrics reinforced epoxy composite laminates has been performed. The tensile, flexural, in-plane shear, interlaminar shear, bearing, and impact properties of the fabricated laminates were investigated. Test specimens were fabricated using vacuum bagging process. Failure modes of all specimens were recorded and discussed. Results proved that the mechanical properties of flax-basalt-glass hybrid laminates are highly dominated by the reinforcement combinations and plies stacking sequence. Hybridizing flax fiber reinforced composite with basalt and/or glass fabrics provides an effective method for enhancing its tensile, flexural, in-plane shear, interlaminar shear, and bearing properties as well as controls the impact strength of the composite. The fabricated hybrids are found to have good specific mechanical properties benefits. Amongst the studied flax/basalt/glass hybrids, FBGs has the highest tensile properties, GBFs has the highest flexural and impact properties, and GFBs has the best shear and bearing properties. Flax-basalt-glass hybrid composites with different layering sequence seem to be an appropriate choice for lightweight load bearing structures.

scholarly journals Influence of laminate direction and glue area on in-plane shear modulus of cross-laminated timber

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Jonas Turesson ◽  
Zahra Sharifi ◽  
Sven Berg ◽  
Mats Ekevad
Keyword(s):  
Finite Element ◽  
Shear Modulus ◽  
Compression Test ◽  
Contact Area ◽  
Tall Buildings ◽  
Shear Stiffness ◽  
Finite Element Simulations ◽  
Plane Shear ◽  
Cross Laminated Timber ◽  
Diagonal Compression

AbstractThe use of cross-laminated timber (CLT) in constructing tall buildings has increased. So, it has become crucial to get a higher in-plane stiffness in CLT panels. One way of increasing the shear modulus, G, for CLT panels can be by alternating the layers to other angles than the traditional 0° and 90°. The diagonal compression test can be used to measure the shear stiffness from which G is calculated. A general equation for calculating the G value for the CLT panels tested in the diagonal compression test was established and verified by tests, finite element simulations and external data. The equation was created from finite element simulations of full-scale CLT walls. By this equation, the influence on the G value was a factor of 2.8 and 2.0 by alternating the main laminate direction of the mid layer from the traditional 90° to 45° and 30°, respectively. From practical tests, these increases were measured to 2.9 and 1.8, respectively. Another influence on the G value was studied by the reduction of the glue area between the layers. It was shown that the pattern of the contact area was more important than the size of the contact area.

Effective shear modulus of a damaged ply in laminate stiffness analysis: Determination and validation

2019 ◽  
Vol 54 (9) ◽  
pp. 1161-1176
Author(s):  
Mohamed Sahbi Loukil ◽  
Janis Varna
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shear Modulus ◽  
Crack Density ◽  
Accurate Solution ◽  
Effective Stiffness ◽  
Crack Face ◽  
Plane Shear ◽  
Stiffness Reduction ◽  
Element Method

The concept of the “effective stiffness” for plies in laminates containing intralaminar cracks is revisited presenting rather accurate fitting expressions for the effective stiffness dependence on crack density in the ply. In this article, the effective stiffness at certain crack density is back-calculated from the stiffness difference between the undamaged and damaged laminate. Earlier finite element method analysis of laminates with cracked 90-plies showed that the effective longitudinal modulus and Poisson’s ratio of the ply do not change during cracking, whereas the transverse modulus reduction can be described by a simple crack density dependent function. In this article, focus is on the remaining effective constant: in-plane shear modulus. Finite element method parametric analysis shows that the dependence on crack density is exponential and the fitting function is almost independent of geometrical and elastic parameters of the surrounding plies. The above independence justifies using the effective ply stiffness in expressions of the classical laminate theory to predict the intralaminar cracking caused stiffness reduction in laminates with off-axis plies. Results are in a very good agreement with (a) finite element method calculations; (b) experimental data, and (c) with the GLOB-LOC model, which gives a very accurate solution in cases where the crack face opening and sliding displacements are accurately described.

458° Flexure Test for Measurement of In-Plane Shear Modulus

2002 ◽  
Vol 36 (20) ◽  
pp. 2313-2337
Author(s):  
F Mujika ◽  
Inaki Mondragon ◽  
L A Berglund ◽  
Janis Varna
Keyword(s):  
Shear Modulus ◽  
Plane Shear ◽  
Flexure Test

Effective shear modulus of piezoelectric film embedded with square nano-fibers under anti-plane shear waves

2014 ◽  
Vol 115 (15) ◽  
pp. 154315 ◽  
Author(s):  
Ming-Juan Huang ◽  
Xue-Qian Fang ◽  
Xing Zhao ◽  
Jin-Xi Liu ◽  
Wen-Jie Feng
Keyword(s):  
Shear Modulus ◽  
Shear Waves ◽  
Piezoelectric Film ◽  
Plane Shear ◽  
Effective Shear Modulus
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