scholarly journals Experimental investigation of CFRP fracture toughness by delamination type

2021 ◽  
Vol 20 (1) ◽  
pp. 97-108
Author(s):  
S. A. Chernyakin
Keyword(s):  
Fracture Toughness ◽  
Experimental Investigation ◽  
Composite Materials ◽  
Numerical Models ◽  
Optical Microscope ◽  
Fracture Mechanisms ◽  
Material Structure ◽  
Propagation Process ◽  
Reinforced Plastics ◽  
Delamination Propagation

The results of analyzing fracture toughness in carbon fiber-reinforced plastics by the type of delamination are presented in the article. The goal of this paper is investigation of delamination propagation process and fracture mechanics parameters in modern CFRPs. This type of composite materials is extensively used in high load aerospace structures. Modern polymer composite materials are the subject of our research. A technique of manufacturing specimens for testing by the vacuum infusion process is presented in the paper. Experimental investigation of delamination propagation process by mode I and II was performed with the aid of up-to-date testing equipment using a special type of specimens such as a double cantilever beam. Researchers usually use this type of specimen for the validation of their numerical models. Critical values of energy release rate and load-displacement curves were obtained for two types of material unidirectional and woven. Examination of microscopic sections of the tested specimens using an optical microscope allowed us to identify the specific fracture mechanisms of material structure.

A Multiscale Framework for Designing High-Toughness Composite Materials

2019 ◽  
Vol 17 (05) ◽  
pp. 1940008
Author(s):  
Yan Li
Keyword(s):  
Fracture Toughness ◽  
Composite Materials ◽  
Ceramic Composites ◽  
Image Correlation ◽  
Analytical Models ◽  
Fracture Mechanisms ◽  
Interface Debonding ◽  
Failure Behavior ◽  
High Toughness ◽  
Fracture Simulation

Development of high-toughness composite materials requires careful microstructure design as geometric distribution of phases, constituent properties and interface attributes combine to influence the deformation and failure behavior of composites. In two-phase composite materials, reinforcement cracking and interface debonding are two competing fracture mechanisms observed during the crack–microstructure interactions. The activation of each fracture mechanism largely depends on the microstructure and ultimately determines the fracture toughness of composites. The objective of this study is to quantify the competition of the two fracture mechanisms as function of microstructure and find their intricate coupling with material fracture toughness. The multiscale material design framework developed here allows fracture toughness to be predicted through cohesive element-based fracture simulation and digital image correlation measurement. Based on the numerical and experimental results, two analytical models are developed for fracture mode determination of both brittle and ductile composites. Although calculations carried out concern ceramic composites Al2O3/SiC and metal matrix composites Al/SiC, the approach developed can be applied to other composite material systems.

Aging of polymer composite materials under loading. (See Beginning in #10-2020)

2020 ◽  
pp. 2-12
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polymer Composite ◽  
Polymer Composite Materials ◽  
Cyclic Loads ◽  
Reinforced Plastics ◽  
Water Exposure ◽  
Laboratory Conditions ◽  
Bending Loads ◽  
Moisture Conditions

A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.

Aging of polymer composite materials under loading

2020 ◽  
pp. 7-18
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polymer Composite ◽  
Polymer Composite Materials ◽  
Cyclic Loads ◽  
Reinforced Plastics ◽  
Water Exposure ◽  
Laboratory Conditions ◽  
Bending Loads ◽  
Moisture Conditions

A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.

scholarly journals Development of Detailed FE Numerical Models for Assessing the Replacement of Metal with Composite Materials Applied to an Executive Aircraft Wing

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 178
Author(s):  
Valerio Acanfora ◽  
Roberto Petillo ◽  
Salvatore Incognito ◽  
Gerardo Mario Mirra ◽  
Aniello Riccio
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Numerical Model ◽  
Numerical Models ◽  
Structural Performance ◽  
Aircraft Wing ◽  
Resin Infusion ◽  
Effectiveness Analysis ◽  
Liquid Resin Infusion ◽  
Process Constraints

This work provides a feasibility and effectiveness analysis, through numerical investigation, of metal replacement of primary components with composite material for an executive aircraft wing. In particular, benefits and disadvantages of replacing metal, usually adopted to manufacture this structural component, with composite material are explored. To accomplish this task, a detailed FEM numerical model of the composite aircraft wing was deployed by taking into account process constraints related to Liquid Resin Infusion, which was selected as the preferred manufacturing technique to fabricate the wing. We obtained a geometric and material layup definition for the CFRP components of the wing, which demonstrated that the replacement of the metal elements with composite materials did not affect the structural performance and can guarantee a substantial advantage for the structure in terms of weight reduction when compared to the equivalent metallic configuration, even for existing executive wing configurations.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

Experimental Investigation on Relative Crack Length For Fracture Toughness of Concrete

2010 ◽  
Vol 146-147 ◽  
pp. 1524-1528 ◽  
Author(s):  
Xue Zhi Wang ◽  
Zong Chao Xu ◽  
Zhong Bi ◽  
Hao Wang
Keyword(s):  
Fracture Toughness ◽  
Experimental Investigation ◽  
Crack Length ◽  
Fracture Toughness Test ◽  
Test Results ◽  
Toughness Test ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Wedge Splitting

The wedge splitting test specimens with three series of different relative crack length were used to study the influences of relative crack length on the fracture toughness of common concrete. The suitable formulation for fracture toughness of concrete with different relative crack length was gotten on comparing between fracture toughness test results and computation results of the model developed from Hu formula.

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