scholarly journals Chain entanglements and fracture energy in interfaces between immiscible polymers

2003 ◽  
Vol 119 (15) ◽  
pp. 8140-8149 ◽  
Author(s):  
Leonardo Silvestri ◽  
Hugh R. Brown ◽  
Stefano Carrà ◽  
Sergio Carrà
Keyword(s):  
Fracture Energy ◽  
Immiscible Polymers ◽  
Chain Entanglements

Fracture Energy and Critical Strength of High Molecular Weight Glassy Polymers

1990 ◽  
Vol 214 ◽  
Author(s):  
Antonios G. Mikos ◽  
Nikolaos A. Peppas
Keyword(s):  
Molecular Weight ◽  
Fracture Energy ◽  
Molecular Model ◽  
Mesh Size ◽  
Glassy Polymers ◽  
Segment Length ◽  
Critical Strength ◽  
Theoretical Predictions ◽  
Entanglement Network ◽  
Chain Entanglements

ABSTRACTThe fracture energy and the critical strength of glassy polymers with molecular weight larger than the critical value for the onset of chain entanglements are proportional to the number of chain segments entangled about a unit plane. A new molecular model is presented to calculate the crossing density of these chain segments when the segment length is a stochastic variable. The crossing density depends on the mesh size of the entanglement network and the number of entanglement network strands per unit volume. Theoretical predictions of the variation of the fracture energy and strength with the molecular weight are compared with experimental results for various glassy polymers.

Fracture of Soft Elastic Foam

2015 ◽  
Vol 83 (3) ◽  
Author(s):  
Zhuo Ma ◽  
Xiangchao Feng ◽  
Wei Hong
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Cell Walls ◽  
Scaling Law ◽  
Phase Field Model ◽  
Base Material ◽  
Network Connectivity ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Order Of Magnitude

Consisting of stretchable and flexible cell walls or ligaments, soft elastic foams exhibit extremely high fracture toughness. Using the analogy between the cellular structure and the network structure of rubbery polymers, this paper proposes a scaling law for the fracture energy of soft elastic foam. To verify the scaling law, a phase-field model for the fracture processes in soft elastic structures is developed. The numerical simulations in two-dimensional foam structures of various unit-cell geometries have all achieved good agreement with the scaling law. In addition, the dependences of the macroscopic fracture energy on geometric parameters such as the network connectivity and spatial orientation have also been revealed by the numerical results. To further enhance the fracture toughness, a type of soft foam structures with nonstraight ligaments or folded cell walls has been proposed and its performance studied numerically. Simulations have shown that an effective fracture energy one order of magnitude higher than the base material can be reached by using the soft foam structure.

scholarly journals Comparative study of elastic properties and mode I fracture energy of carbon nanotube/epoxy and carbon fibre/epoxy laminated composites

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Jyotikalpa Bora ◽  
Sushen Kirtania
Keyword(s):  
Carbon Nanotube ◽  
Carbon Fibre ◽  
Fracture Energy ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Laminated Composite ◽  
Fe Analysis ◽  
Mode I ◽  
Mode I Fracture

Abstract A comparative study of elastic properties and mode I fracture energy has been presented between conventional carbon fibre (CF)/epoxy and advanced carbon nanotube (CNT)/epoxy laminated composite materials. The volume fraction of CNT fibres has been considered as 15%, 30%, and 60% whereas; the volume fraction of CF has been kept constant at 60%. Three stacking sequences of the laminates viz.[0/0/0/0], [0/90/0/90] and [0/30/–30/90] have been considered in the present analysis. Periodic microstructure model has been used to calculate the elastic properties of the laminated composites. It has been observed analytically that the addition of only 15% CNT in epoxy will give almost the same value of longitudinal Young’s modulus as compared to the addition of 60% CF in epoxy. Finite element (FE) analysis of double cantilever beam specimens made from laminated composite has also been performed. It has been observed from FE analysis that the addition of 15% CNT in epoxy will also give almost the same value of mode I fracture energy as compared to the addition of 60% CF in epoxy. The value of mode I fracture energy for [0/0/0/0] laminated composite is two times higher than the other two types of laminated composites.

Estimation of Fracture Toughness JIC by Miniature Specimen Hydraulic Bulge Test

2017 ◽  
Vol 898 ◽  
pp. 753-757
Author(s):  
Le Le Gui ◽  
Tong Xu ◽  
Bin An Shou ◽  
Han Kui Wang ◽  
Jing Xiang
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Fracture Strain ◽  
Bulge Test ◽  
Miniature Specimen ◽  
Hydraulic Bulge Test ◽  
Hydraulic Bulge ◽  
Resistance Curves ◽  
Miniature Specimens ◽  
Load Deflection Curve

The fracture toughness tests and a new miniature specimen technology named hydraulic bulge test (HBT) of 3Cr1Mo1/4V at four service time were carried out. Four J-R resistance curves by single-specimen method with one inch CT specimens were obtained to compute the JIC. Different definitions of equivalent fracture strain according to the section morphologies of HBT testing specimens were compared, and fracture energy of miniature specimens with three different thicknesses (0.4mm, 0.5mm and 0.6mm) were also calculated. Results showed that the typical HBT load-deflection curve can be divided into four sections like SPT curve. Equivalent fracture strain and fracture energy EHB can be chosen as two fracture parameters for the HBT specimen. Ductile fracture toughness JIC can be related approximately linearly to both the equivalent fracture strain and fracture energy EHB.

Studies on effect of steel fiber and coarse aggregate on fracture properties of self compacting concrete using wedge splitting test

2019 ◽  
Vol 11 (6) ◽  
pp. 751-767
Author(s):  
Raja Rajeshwari B. ◽  
Sivakumar M.V.N.
Keyword(s):  
Fracture Energy ◽  
Coarse Aggregate ◽  
Peak Load ◽  
Mouth Opening ◽  
Test Method ◽  
Crack Mouth Opening Displacement ◽  
Fine Aggregate ◽  
Content Type ◽  
Fracture Properties ◽  
Splitting Test

Purpose Fracture properties depend on the type of material, method of testing and type of specimen. The purpose of this paper is to evaluate fracture properties by adopting a stable test method, i.e., wedge split test. Design/methodology/approach Coarse aggregate of three different sizes (20 mm, 16 mm and 12.5 mm), three ratios of coarse aggregate, fine aggregate (CA:FA) (50:50, 45:55, 40:60), presence of steel fibers, and specimens without and with guide notch were chosen as parameters of the study. Findings Load-crack mouth opening displacement curves indicate that for both fibrous and non-fibrous mixes, higher volume of aggregate and higher size of coarse aggregate have high fracture energy. Originality/value For all volumes of coarse aggregate, it was noticed that specimens with 12.5 mm aggregate size achieved highest peak load and abrupt drop post-peak. The decrease in coarseness of internal structure of concrete (λ) resulted in the increase of fracture energy.

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