Quantitative Adjustment to the Molecular Energy Parameter in the Lake–Thomas Theory of Polymer Fracture Energy

2019 ◽  
Vol 52 (7) ◽  
pp. 2772-2777 ◽  
Author(s):  
Shu Wang ◽  
Sergey Panyukov ◽  
Michael Rubinstein ◽  
Stephen L. Craig
Keyword(s):  
Fracture Energy ◽  
Energy Parameter ◽  
Polymer Fracture

Estimation of Charpy Index Temperature of SA 508 Mn-Mo-Ni Low Alloy Steels at 41J Using Small Punch Tests

2020 ◽  
Author(s):  
Jongmin Kim ◽  
Seokmin Hong ◽  
Taekyoung Lee ◽  
Minchul Kim
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Power Plants ◽  
Energy Parameter ◽  
Charpy Impact ◽  
Maximum Load ◽  
Transition Curve ◽  
Displacement Curve ◽  
Low Alloy Steels ◽  
Small Punch

Abstract Small Punch (SP) test is one of the miniature test methods, which is a quasi-destructive testing method that evaluates the mechanical properties from limited volumes of materials. Structural materials in nuclear power plants experience degradation in the neutron irradiation environment during the operation, and this aging is assessed by measuring the Charpy index temperature shift of materials at 41J (T41J). However, there are many difficulties in deriving T41J or the fracture toughness from the SP test due to the difference in the failure mode between the SP tests and the conventional Charpy impact and fracture toughness tests. In this study, a method to predict the index temperature at 41J by using the key parameters obtained from SP load-displacement curve was proposed. T41J prediction methods using the fracture energy and displacement after the maximum load in SP test were proposed, and an analysis of the correlation between the key parameters of SP test and the fracture toughness values was performed. As a result of applying displacement after the maximum load parameter of SP curve, it showed better prediction than the fracture energy parameter, and the fracture mode in transition curve of SP was consistent with that of Charpy impact test.

scholarly journals Power-Oriented Monitoring of Clock Signals in FPGA Systems for Critical Application

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 792
Author(s):  
Oleksandr Drozd ◽  
Grzegorz Nowakowski ◽  
Anatoliy Sachenko ◽  
Viktor Antoniuk ◽  
Volodymyr Kochan ◽  
...  
Keyword(s):  
Power Consumption ◽  
Computer Aided Design ◽  
Computer Systems ◽  
Energy Parameter ◽  
Online Testing ◽  
Thermal Monitoring ◽  
Energy Parameters ◽  
Current Consumption ◽  
Computer Aided ◽  
Aided Design

This paper presents a power-oriented monitoring of clock signals that is designed to avoid synchronization failure in computer systems such as FPGAs. The proposed design reduces power consumption and increases the power-oriented checkability in FPGA systems. These advantages are due to improvements in the evaluation and measurement of corresponding energy parameters. Energy parameter orientation has proved to be a good solution for detecting a synchronization failure that blocks logic monitoring circuits. Key advantages lay in the possibility to detect a synchronization failure hidden in safety-related systems by using traditional online testing that is based on logical checkability. Two main types of power-oriented monitoring are considered: detecting a synchronization failure based on the consumption and the dissipation of power, which uses temperature and current consumption sensors, respectively. The experiments are performed on real FPGA systems with the controlled synchronization disconnection and the use of the computer-aided design (CAD) utility to estimate the decreasing values of the energy parameters. The results demonstrate the limited checkability of FPGA systems when using the thermal monitoring of clock signals and success in monitoring by the consumption current.

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 Finite Element Study for Magnetohydrodynamic (MHD) Tangent Hyperbolic Nanofluid Flow over a Faster/Slower Stretching Wedge with Activation Energy

Mathematics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 25
Author(s):  
Bagh Ali ◽  
Rizwan Ali Naqvi ◽  
Amna Mariam ◽  
Liaqat Ali ◽  
Omar M. Aldossary
Keyword(s):  
Activation Energy ◽  
Finite Element ◽  
Volume Fraction ◽  
Wedge Angle ◽  
Energy Parameter ◽  
Reliability And Validity ◽  
Lewis Number ◽  
Convergence Criteria ◽  
Convective Boundary ◽  
Differential Formulation

The below work comprises the unsteady flow and enhanced thermal transportation for Carreau nanofluids across a stretching wedge. In addition, heat source, magnetic field, thermal radiation, activation energy, and convective boundary conditions are considered. Suitable similarity functions use to transmuted partial differential formulation into the ordinary differential form, which is solved numerically by the finite element method and coded in Matlab script. Parametric computations are made for faster stretch and slowly stretch to the surface of the wedge. The progressing value of parameter A (unsteadiness), material law index ϵ, and wedge angle reduce the flow velocity. The temperature in the boundary layer region rises directly with exceeding values of thermophoresis parameter Nt, Hartman number, Brownian motion parameter Nb, ϵ, Biot number Bi and radiation parameter Rd. The volume fraction of nanoparticles rises with activation energy parameter EE, but it receded against chemical reaction parameter Ω, and Lewis number Le. The reliability and validity of the current numerical solution are ascertained by establishing convergence criteria and agreement with existing specific solutions.

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.

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