scholarly journals Fracture Criterion of Single Fiber-Composite under Thermal and Tensile Loadings Based on Energy Release Rate

2003 ◽  
Vol 52 (7) ◽  
pp. 815-820
Author(s):  
Tadanobu INOUE ◽  
Shojiro OCHIAI ◽  
Masaki HOJO ◽  
Kotobu NAGAI
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Criterion ◽  
Fiber Composite ◽  
Single Fiber

scholarly journals Adhesion of Multifunctional Substrates for Integrated Cure Monitoring Film Sensors to Carbon Fiber Reinforced Polymers

2020 ◽  
Vol 4 (3) ◽  
pp. 138
Author(s):  
Alexander Kyriazis ◽  
Kais Asali ◽  
Michael Sinapius ◽  
Korbinian Rager ◽  
Andreas Dietzel
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Fiber Composite ◽  
Critical Energy ◽  
Negative Influence ◽  
Fiber Reinforced Polymers ◽  
Critical Energy Release Rate ◽  
Novel Approach ◽  
Form Closure

During fiber composite production, the quality of the manufactured parts can be assured by measuring the progress of the curing reaction. Dielectric film sensors are particularly suitable for this measurement task, as they can quantify the degree of curing very specifically and locally. These sensors are usually manufactured on PI films, which can lead to delaminations after integration. Other authors report that this negative influence can be reduced by miniaturization and a suitable shaping of the sensors. This article pursues as an alternative, a novel approach to achieve a material closure instead of a geometrically generated form closure by choosing suitable thermoplastic materials. Thermoplastic films made of PEI, PES and PA6 are proposed as carrier substrates for thin film sensors. They are investigated with regard to their mechanical effects in FRP. The experiments show that the integration of PES and PEI in FRP has the best shear strength, but PA6 leads to a higher critical energy release rate during crack propagation in mode I. For PI, a locally strongly scattering critical energy release rate was observed. Neither in tensile nor in Compression After Impact (CAI) tests a significant influence of the films on these characteristic values could be proven.

Electrical Nonlinearity in Fracture of Piezoelectric Ceramics

1997 ◽  
Vol 50 (11S) ◽  
pp. S56-S63 ◽  
Author(s):  
Chandler C. Fulton ◽  
Huajian Gao
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Criterion ◽  
Piezoelectric Ceramics ◽  
Remarkable Feature ◽  
Cracking Behavior ◽  
Poling Direction ◽  
Dugdale’S Model ◽  
Electrical Nonlinearity

The structural reliability of piezoelectric ceramics in smart sensors and actuators is hindered by the lack of an appropriate fracture mechanics model. Recent experimental observations of their cracking behavior under combined electrical and mechanical loads contradict predictions made by the linear theory. Evidently, a fracture criterion suitable for piezoelectrics must account for material nonlinearity. Because these materials are typically mechanically brittle, we expect electrical ductility to be the dominant effect. By adopting a multiscale viewpoint, we identify a region of electrical nonlinearity near the crack tip in which the mechanical response of the material remains linear. The equilibrium equations for a fully anisotropic solid have closed-form solutions if the material’s behavior is assumed to be entirely linear outside of the plane of the crack. This approximation is equivalent to Dugdale’s model of the plastic zone in cracked metal sheets. The energy release rate derived using this load for specimens with cracks perpendicular to the poling direction. A remarkable feature of our model is that the energy release rate is strictly independent of the form of the nonlinear electrical constitutive relation. In fact, the material may even experience domain switching in the Dugdale zone without affecting the fracture criterion determined by our formulation.

Calculating Energy Release Rate as a Function of Crack Length Using a Multiple-Step Crack Closure Technique in Tire Finite Element Models

2018 ◽  
Vol 46 (3) ◽  
pp. 130-152
Author(s):  
Dennis S. Kelliher
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Crack Closure ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Three Dimensions ◽  
Quantitative Prediction ◽  
Closure Technique

ABSTRACT When performing predictive durability analyses on tires using finite element methods, it is generally recognized that energy release rate (ERR) is the best measure by which to characterize the fatigue behavior of rubber. By addressing actual cracks in a simulation geometry, ERR provides a more appropriate durability criterion than the strain energy density (SED) of geometries without cracks. If determined as a function of crack length and loading history, and augmented with material crack growth properties, ERR allows for a quantitative prediction of fatigue life. Complications arise, however, from extra steps required to implement the calculation of ERR within the analysis process. This article presents an overview and some details of a method to perform such analyses. The method involves a preprocessing step that automates the creation of a ribbon crack within an axisymmetric-geometry finite element model at a predetermined location. After inflating and expanding to three dimensions to fully load the tire against a surface, full ribbon sections of the crack are then incrementally closed through multiple solution steps, finally achieving complete closure. A postprocessing step is developed to determine ERR as a function of crack length from this enforced crack closure technique. This includes an innovative approach to calculating ERR as the crack length approaches zero.

scholarly journals Effect of the Characteristic Size and Content of Graphene on the Crack Propagation Path of Alumina/Graphene Composite Ceramics

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 611
Author(s):  
Benshuai Chen ◽  
Guangchun Xiao ◽  
Mingdong Yi ◽  
Jingjie Zhang ◽  
Tingting Zhou ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Volume Content ◽  
Phase Interface ◽  
Average Energy ◽  
Characteristic Size ◽  
Composite Ceramics ◽  
Graphene Composite

In this paper, the Voronoimosaic model and the cohesive element method were used to simulate crack propagation in the microstructure of alumina/graphene composite ceramic tool materials. The effects of graphene characteristic size and volume content on the crack propagation behavior of microstructure model of alumina/graphene composite ceramics under different interfacial bonding strength were studied. When the phase interface is weak, the average energy release rate is the highest as the short diameter of graphene is 10–50 nm and the long diameter is 1600–2000 nm. When the phase interface is strong, the average energy release rate is the highest as the short diameter of graphene is 50–100 nm and the long diameter is 800–1200 nm. When the volume content of graphene is 0.50 vol.%, the average energy release rate reaches the maximum. When the velocity load is 0.005 m s−1, the simulation result is convergent. It is proven that the simulation results are in good agreement with the experimental phenomena.

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