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.

The Torsional Fatigue Behaviour of the In-Plane Shear Modulus of Composite Materials

1992 ◽  
pp. 293-300
Author(s):  
M. Bruggeman ◽  
L. De Munck ◽  
D. Van Hemelrijck ◽  
F. Boulpaep ◽  
L. Schillemans ◽  
...  
Keyword(s):  
Composite Materials ◽  
Shear Modulus ◽  
Fatigue Behaviour ◽  
Plane Shear ◽  
Torsional Fatigue

Assessment of Theories of Failure for Multi-Directional Composites Laminates: A Fuzzy - AHP Approach

2015 ◽  
Vol 830-831 ◽  
pp. 721-726 ◽  
Author(s):  
Ashutosh Mishra ◽  
Mohan Kumar Pradhan
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Fuzzy Ahp ◽  
Stress Strain ◽  
Axial Strength ◽  
Overall Effectiveness

In this research, the analysis has been made amongst the different 'theories of failure' for composite materials. All theories which include bi-axial strength envelopes and stress–strain curves for a range of multi-directional laminates, loaded under uni-axial or bi-axial conditions.The predictions and experimental data have been analyzed, to identify the strengths and weakness, together with a ranking of the overall effectiveness of each theory, which has been made by the AHP-MCDM tool to facilitate the reader to select the best theory for given design situation.

scholarly journals Degradation of the In-plane Shear Modulus of Structural BFRP Laminates Due to High Temperature

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3361 ◽  
Author(s):  
Yu-Jia Hu ◽  
Cheng Jiang ◽  
Wei Liu ◽  
Qian-Qian Yu ◽  
Yun-Lai Zhou
Keyword(s):  
High Temperature ◽  
Shear Modulus ◽  
Image Correlation ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Plane Shear ◽  
Analytical Derivation ◽  
Reinforced Polymer

The behavior of fiber reinforced polymer (FRP) composites at high temperature is a critical issue that needs to be clearly understood for their structural uses in civil engineering. However, due to technical difficulties during testing at high temperature, limited experimental investigations have been conducted regarding the thermal behavior of basalt fiber reinforced polymer (BFRP) composites, especially for the in-plane shear modulus of BFRP laminates. To this end, both an analytical derivation and an experimental program were carried out in this work to study the in-plane shear modulus of BFRP laminates. After the analytical derivation, the in-plane shear modulus was investigated as a function of the elastic modulus in different directions (0°, 45° and 90° of the load-to-fiber angle) and Poisson's ratio in the fiber direction. To obtain the in-plane shear modulus, the four parameters were tested at different temperatures from 20 to 250 °C. A novel non-contacting digital image correlation (DIC) sensing system was adopted in the high-temperature tests to measure the local strain field on the FRP samples. Based on the test results, it was found that the elastic moduli in different directions were reduced to a very low level (less than 20%) from 20 to 250 °C. Furthermore, the in-plane shear modulus of BFRP at 250 °C was only 3% of that at 20 °C.

scholarly journals A General Temperature-Dependent Stress–Strain Constitutive Model for Polymer-Bonded Composite Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1393
Author(s):  
Xiaochang Duan ◽  
Hongwei Yuan ◽  
Wei Tang ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Composite Materials ◽  
Constitutive Model ◽  
Model Parameters ◽  
Temperature Dependent ◽  
Stress Strain ◽  
Proposed Model ◽  
Single Temperature ◽  
Testing Data ◽  
Bonded Composite ◽  
Tension And Compression

This study develops a general temperature-dependent stress–strain constitutive model for polymer-bonded composite materials, allowing for the prediction of deformation behaviors under tension and compression in the testing temperature range. Laboratory testing of the material specimens in uniaxial tension and compression at multiple temperatures ranging from −40 ∘C to 75 ∘C is performed. The testing data reveal that the stress–strain response can be divided into two general regimes, namely, a short elastic part followed by the plastic part; therefore, the Ramberg–Osgood relationship is proposed to build the stress–strain constitutive model at a single temperature. By correlating the model parameters with the corresponding temperature using a response surface, a general temperature-dependent stress–strain constitutive model is established. The effectiveness and accuracy of the proposed model are validated using several independent sets of testing data and third-party data. The performance of the proposed model is compared with an existing reference model. The validation and comparison results show that the proposed model has a lower number of parameters and yields smaller relative errors. The proposed constitutive model is further implemented as a user material routine in a finite element package. A simple structural example using the developed user material is presented and its accuracy is verified.

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