Comparison of out-of-plane tensile moduli of CFRP laminates obtained by 3-point bending and direct loading tests

Composite laminates are characterized by high mechanical in-plane properties and poor out-of-plane characteristics. This issue becomes even more relevant when dealing with impact phenomena occurring in the transverse direction. In aeronautics, Low Velocity Impacts (LVIs) may occur during the service life of the aircraft. LVI may produce damage inside the laminate, which are not easily detectable and can seriously degrade the mechanical properties of the structure. In this paper, a numerical-experimental investigation is carried out, in order to study the mechanical behavior of rectangular laminated specimens subjected to low velocity impacts. The numerical model that best represents the impact phenomenon has been chosen by numerical–analytical investigations. A user defined material model (VUMAT) has been developed in Abaqus/Explicit environment to simulate the composite intra-laminar damage behavior in solid elements. The analyses results were compared to experimental test data on a laminated specimen, performed according to ASTM D7136 standard, in order to verify the robustness of the adopted numerical model and the influence of modeling parameters on the accuracy of numerical results.

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Evaluation of fatigue life of thick CFRP laminates with toughened interlaminar layers in out-of-plane and in-plane transverse directions

Transactions of the JSME (in Japanese) ◽

10.1299/transjsme.16-00571 ◽

2017 ◽

Vol 83 (851) ◽

pp. 16-00571-16-00571 ◽

Cited By ~ 1

Author(s):

Sen SEKI ◽

Tomoki ARAI ◽

Shinichiro FUKUSHIMA ◽

Atsushi HOSOI ◽

Yuzo FUJITA ◽

...

Keyword(s):

Fatigue Life ◽

Cfrp Laminates ◽

Plane Transverse ◽

Out Of Plane

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Effect of ply angle misalignment on out-of-plane deformation of symmetrical cross-ply CFRP laminates: Accuracy of the ply angle alignment

Composite Structures ◽

10.1016/j.compstruct.2010.10.019 ◽

2011 ◽

Vol 93 (4) ◽

pp. 1225-1230 ◽

Cited By ~ 22

Author(s):

Yoshihiko Arao ◽

Jun Koyanagi ◽

Shin Utsunomiya ◽

Hiroyuki Kawada

Keyword(s):

Plane Deformation ◽

Cfrp Laminates ◽

Out Of Plane

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Out-of-Plane Tensile Modulus of CFRP Laminates by 3-Point Bending Test

Journal of the Japan Society for Composite Materials ◽

10.6089/jscm.39.184 ◽

2013 ◽

Vol 39 (5) ◽

pp. 184-192 ◽

Cited By ~ 2

Author(s):

Eiichi HARA ◽

Tomohiro YOKOZEKI ◽

Hiroshi HATTA ◽

Yutaka IWAHORI ◽

Takashi ISHIKAWA

Keyword(s):

Tensile Modulus ◽

Bending Test ◽

Cfrp Laminates ◽

Out Of Plane

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Analysis of measurements of defects in multiaxial warp knitted fabrics for CFRP composites

10.32920/ryerson.14664231 ◽

2021 ◽

Author(s):

Diane Suk-Ching Liu

Keyword(s):

Image Analysis ◽

Standard Deviation ◽

Carbon Fibre ◽

Compression Strength ◽

Cell Model ◽

Unit Cell ◽

Sample Standard Deviation ◽

Cfrp Laminates ◽

Laboratory Results ◽

Out Of Plane

Multiaxial Warp Knitted (MWK) Fabrics are used to create Carbon Fibre Reinforced Plastic (CFRP) laminates. In contrast to Prepregs, CFRP laminates made with MWK fabrics are of interest because they could lower costs and processing time by being already constructed with multiple layers and through the use of a hot air oven instead of an autoclave. Defect in the form of fibre angle orientation plays an important role in the compression strength for laminates made with MWK fabrics. The in-plane and out-of-plane waviness of the fibres were characterised by the standard deviation of the angular waviness: sample Standard deviation of Fibre In-plane (SFI) and the sample Standard deviation of Fibre Out-of-plane (SFO). The SFI value was found in two ways: analysis (Multiple Field Image Analysis (MFIA) technique) software and Fibre Image Analysis software. Measurements of the holes in the carbon fibre textile, colloquially known as “fisheyes,” caused by sewing the textile together were also gathered. The SFI, SFO, and “fisheye” dimensions were together used in the FMB-PMB model and the Unit Cell Model to calculate the compression strength. These predicted compression strengths were compared to the laboratory results. Also, a reliability model was developed to find R, the reliability of each textile, to be used as a textile classification tool. It has been found that the compression strength predictions found using analysis and Fibre Image Analysis yielded similar results, with predictions from analysis closer to the laboratory results. The R value yielded a positive correlation with the results from analysis. A large percentage of difference between the predicted and the actual compression strength was observed for some textiles. This could be attributed to the inherent lack of regularity for some of the examined textiles and variability in determining the SFI and “fisheye” parameters. Improvements would involve devising rules and methods to determine the SFI and “fisheye” parameters, modifying the FMB-PMB and Unit Cell Models, and making the analysis process faster and more applicable for on-line quality process control.

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Seismic Performance of Precast Concrete Composite Shear Walls with Multiple Boundary Elements

Journal of Earthquake and Tsunami ◽

10.1142/s1793431119400062 ◽

2019 ◽

Vol 13 (03n04) ◽

pp. 1940006

Author(s):

W. C. Xue ◽

Y. Li ◽

L. Cai ◽

X. Hu

Keyword(s):

Precast Concrete ◽

Shear Walls ◽

Boundary Elements ◽

Shear Wall ◽

Control Specimen ◽

Test Results ◽

Out Of Plane ◽

Loading Tests ◽

Composite Shear ◽

Scale Shear

Compared with traditional precast concrete composite shear walls (PCCSWs) with two boundary elements adjacent to edges, the PCCSWs with multiple boundary elements investigated in this paper have extra boundary elements at the intersections with other shear walls. In this paper, low reversed cyclic loading tests were conducted on three full-scale shear wall specimens with multiple boundary elements under in-plane loading and two full-scale shear wall specimens under out-of-plane loading. The in-plane loaded specimens included a PCCSW with double precast layers (i.e. precast concrete double skin shear wall, PCDSSW), a PCCSW with single precast layer, and a cast-in-pace (CIP) control specimen, whereas the out-of-plane loaded specimens included a PCDSSW and a CIP control specimen. Test results revealed that all specimens failed in bending. The hysteresis loops of the precast composite specimens were stable but slightly pinching, which were similar to those of the corresponding CIP control specimen. Compared with the CIP specimens, the PCDSSWs showed similar energy dissipation. The loading capacity of the precast composite specimens was generally a little lower than that of the corresponding CIP specimen with difference not more than 15%. In the in-plane loading tests, the PCDSSW reached higher displacement ductility (2.45) than the CIP specimen (1.88), whereas the ductility of the PCCSW with single precast layer was relatively low. Regarding the specimens under out-of-plane loading, the ductility of the PCDSSW (3.83) was close to that of the CIP specimen (3.02). Moreover, the stiffness degradation of the precast composite specimens was found to be comparable to that of the control specimens. Based on the test results, a restoring force model was developed.

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