On the validation of a damage mesomodel for laminated composites by means of open-hole tensile tests on quasi-isotropic laminates

2011 ◽  
Vol 42 (10) ◽  
pp. 1515-1524 ◽  
Author(s):  
E. Abisset ◽  
F. Daghia ◽  
P. Ladevèze
Keyword(s):  
Laminated Composites ◽  
Tensile Tests ◽  
Open Hole

Progressive Fatigue Damage Simulation in Laminated Composites Based on Explicit Finite Element Formulation

2019 ◽  
Vol 64 (2) ◽  
pp. 1-12
Author(s):  
Yuri Nikishkov ◽  
Guillaume Seon ◽  
Andrew Makeev
Keyword(s):  
Finite Element ◽  
Laminated Composites ◽  
Test Methods ◽  
Remaining Useful Life ◽  
Image Correlation ◽  
Progressive Damage ◽  
Damage Analysis ◽  
Explicit Finite Element ◽  
Analysis Methods ◽  
Open Hole

Advanced polymeric composites are playing a major role in designing high-performance and lightweight vertical lift structures. However, uncertain residual strength and remaining useful life of the composite rotor and airframe structures due to complexity of failure mechanisms and susceptibility to manufacturing irregularities, which may be precursors to structural damage, impose risks that cannot be mitigated exclusively by time-consuming and costly experimental iterations. Validated analysis techniques accelerating design, certification, and qualification of composite structures are needed. Our team has been taking essential steps toward improving confidence in material qualification for laminated composites. The first step started with our reduced lamina test methods, short-beam shear, and small-plate twist based on digital image correlation measuring as a subset the standard material properties and, in addition, key properties that cannot be currently measured using any standard test methods. The lamina properties provide essential material input data for laminate analysis. The laminate analysis was the second step increasing confidence in material qualification. A known weakness of the existing progressive damage analysis methods is the lack of effective techniques to predict ultimate failure. The newly developed methodology relies on explicit finite element modeling and eliminates convergence issues in the ply-level progressive damage analysis methods due to severe nonlinear discontinuities after propagation of damage beyond detectable size. This work shows results of applying this methodology to nanosilica-toughened IM7/PMT-F3GHT open-hole tension strength/fatigue, open-hole compression strength/fatigue, and bearing strength multidirectional laminate configurations. The ability to predict progression of damage from initiation to ultimate strength and fatigue for advanced material systems including IM7/PMT-F3GHT carbon/epoxy reinforced by nanosilica has been demonstrated for the first time.

Experimental System and Validation for Energy-Based Characterization

2011 ◽  
Author(s):  
Jan Wei Pan ◽  
Jinquan Cheng ◽  
Tomonari Furukawa ◽  
Athanasios P. Iliopoulos ◽  
John G. Michopoulos
Keyword(s):  
Elastic Constants ◽  
Testing Machine ◽  
Experimental System ◽  
Tensile Tests ◽  
Recursive Estimation ◽  
Sensor Data ◽  
External Work ◽  
Measurement Results ◽  
Uniaxial Testing ◽  
Open Hole

This paper presents the experimental system and experimental validation of an energy-based characterization for the identification of elastic constants. Unlike the standard uniaxial testing machine, which uses a contact strain sensor such as extensometer, the developed system uses a non-contact optic sensor as an advantage to measure and derive external work and strain measurements for characterizing the elastic constants. To investigate the validity of the energy-based characterization, a graphical user interface and the experimental system were developed for the tensile tests of aluminum open-hole specimens. During the validation, the means and variances of the characterization results were analyzed. The reliability of its recursive estimation was further investigated by the convergence of covariance at every new measurement. Results showed that the recursive estimation allows identification of elastic constants of a test coupon at every acquisition of sensor data in an online manner. The identification of all the constants during deformation thus demonstrated the overall validity and efficiency of the energy-based characterization.

scholarly journals Discrete ply modelling of open hole tensile tests

2014 ◽  
Vol 113 ◽  
pp. 369-381 ◽  
Author(s):  
Victor Achard ◽  
Christophe Bouvet ◽  
Bruno Castanié ◽  
Clément Chirol
Keyword(s):  
Tensile Tests ◽  
Open Hole

Effects of Heating Period of Time on Tensile Property of Plain Woven Fabric/Epoxy Resin Laminated Composites at High Temperature

2010 ◽  
Vol 34-35 ◽  
pp. 1397-1401
Author(s):  
Guang Wei Chen ◽  
Gui Fang He ◽  
Jia Lu Li
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Epoxy Resin ◽  
Tensile Property ◽  
Laminated Composites ◽  
Tensile Load ◽  
Tensile Tests ◽  
Woven Fabric ◽  
Resin Composites ◽  
Heating Period

The purpose of this paper is to investigate the tensile property of laminated epoxy resin composites reinforced by carbon fiber plain woven fabric with different heating period of time at relatively high temperature. For this purpose, the tensile tests of laminated resin composites are carried out at 150°C and 180°C with 15 minutes, 10 hours and 30 hours heating period of time, respectively. The reasons for the variations of tensile property of these composites with different heating period of time at 150°C and 180°C are analyzed. At 150°C and 180 °C，with heating period of time increasing the tensile strength of samples keep the same level. However at 180 °C the average tensile strength of samples is decreased by 14.95% compared with that at 150°C and the variation coefficient (CV) of tensile strengths at 180°C is much more than that at 150°C. These show that the tensile strength of resin laminated composites is sensitive at high temperature, although the tensile strength of resin laminated composites keeps the same level at same temperature with different heating period of time. The reason of the tensile strength of resin laminated composites decreased at high temperature is that resin has been damaged，which losing the adhesion of fiber and resin, so that these make resin and fiber can not bear the tensile load together. The research results will provide a basic reference for the application of plain woven fabric reinforced laminated resin composites with long using period of time at high temperature.

Effects of ply thickness and 0°-layer ratio on failure mechanism of open-hole and filled-hole tensile tests of thin-ply composite laminates

2021 ◽  
pp. 114926
Author(s):  
Ryoma Aoki ◽  
Ryo Higuchi ◽  
Tomohiro Yokozeki ◽  
Kazuyuki Aoki ◽  
Shigekazu Uchiyama ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Composite Laminates ◽  
Tensile Tests ◽  
Open Hole

Static strength prediction in laminated composites by using discrete damage modeling

2016 ◽  
Vol 51 (10) ◽  
pp. 1473-1492 ◽  
Author(s):  
Kevin Hoos ◽  
Endel V Iarve ◽  
Michael Braginsky ◽  
Eric Zhou ◽  
David H Mollenhauer
Keyword(s):  
Compressive Strength ◽  
Input Data ◽  
Damage Mechanics ◽  
Laminated Composites ◽  
Matrix Cracking ◽  
Damage Modeling ◽  
Fiber Failure ◽  
Failure Patterns ◽  
Open Hole ◽  
Discrete Damage Modeling

Discrete Damage Modeling of complex local failure patterns in laminated composites including matrix cracking, delamination, and fiber failure was performed. Discrete Damage Modeling uses the Regularized eXtended Finite Element Method for the simulation of matrix cracking at initially unknown locations and directions independent of the mesh orientation. Cohesive interface model is used both for Mesh Independent Cracking as well as delamination propagation. The fiber failure mode is modeled by two different methods in tension and compression. Tensile failure is predicted by Critical Failure Volume criterion, which takes into account volumetric scaling of tensile strength. Compression fiber failure is simulated with a single parameter continuum damage mechanics model with non-compressibility condition in the failed region. Ply level characterization input data were used for prediction of notched and unnotched laminate strength. All input data required for model application is directly measured by ASTM tests except tensile fiber scaling parameter and compression fiber failure fracture toughness, which were taken from literature sources. The model contains no internal calibration parameters. Tensile and compressive strength of unnotched and open hole composite laminates IM7/977-3 has been predicted and compared with experimental data. Three different layups, [0/45/90/−45]2S, [30/60/90/−60/−30]2S, and the [60/0/−60]3S, were modeled and tested and showed good agreement with experiment in the case of tensile loading, whereas the compressive strength was generally under predicted for unnotched laminates and overpredicted for open hole laminates.

scholarly journals Evaluation of the Sensitivity of Various Reinforcement Patterns for Structural Carbon Fibers to Open Holes during Tensile Tests

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4287
Author(s):  
Elena Strungar ◽  
Dmitrii Lobanov ◽  
Valery Wildemann
Keyword(s):  
Statistical Processing ◽  
Correlation Method ◽  
Polymeric Composite ◽  
Tensile Tests ◽  
Ultimate Stress ◽  
Testing System ◽  
Fiber Tension ◽  
Reinforcing Fibers ◽  
Open Hole ◽  
Structural Carbon

This paper is devoted to the experimental study of polymeric composite specimens, with various types of reinforcement, in order to evaluate the breaking strength of specimens with open holes when undergoing uniaxial compression and tensile tests. Four types of interlaced 3D woven preforms were considered (orthogonal, orthogonal combined, with pairwise inter-layer reinforcement, and with pairwise inter-layer reinforcement and a longitudinal layer), with a layered preform used for comparison. Tensile tests of solid specimens without a hole, under ASTM D 3039, and of specimens with an open hole, under ASTM D 5766, were carried out using the Instron 5989 universal electromechanical testing system. Movements and strains on the specimen surface were recorded using a Vic-3D contactless optical video system and the digital images correlation method (DIC). For all the series of carbon fiber tension specimens, strain and stress diagrams, mechanical characteristics, and statistical processing for 10 specimens were obtained. The paper evaluated deformation fields for certain points in time; the obtained fields showed an irregular distribution of deformation and dependency on types of reinforcing fibers. A coefficient of strength variation is introduced, which is defined as a ratio of the ultimate stress limits obtained on solid samples with and without open holes. Within the framework of ASTM D 5766, when calculating the ultimate stress, the hole is not taken into account, and the paper shows that for certain structures a hole cannot be excluded. The hole size must not be neglected when calculating the ultimate stress.

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