scholarly journals Synergy between Phenoxy and CSR Tougheners on the Fracture Toughness of Highly Cross-Linked Epoxy-Based Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2477
Author(s):  
Pascal Van Velthem ◽  
Sarah Gabriel ◽  
Thomas Pardoen ◽  
Christian Bailly ◽  
Wael Ballout
Keyword(s):  
Fracture Toughness ◽  
High Performance ◽  
Total Concentration ◽  
Compression Modulus ◽  
Equal Weight ◽  
System A ◽  
Viscosity Increase ◽  
Interlaminar Shear ◽  
Modulus Reduction ◽  
Synergistic Increase

A remarkable synergistic increase in fracture toughness by 130% is demonstrated for a CFRP high performance epoxy composite when adding an equal weight combination of phenoxy thermoplastic and core-shell rubber (CSR) toughening agents, as compared to a single toughener at a comparable total concentration of around 10 wt%. The dual-toughened matrix exhibits an unusual morphological arrangement of the two toughener agents. The interlaminar shear strength of the composites is also synergistically improved by about 75% as compared to the reference while the compression modulus reduction and viscosity increase are significantly smaller than for the single phenoxy toughened system. A partial filtering of the CSR particles by the dense CF fabric during pre-pregging leads to a less than optimum CSR dispersion in the composites, showing that the synergy can be further optimized, possibly to the same level as the unreinforced systems.

Effect of Graphene Oxide on Interfacial Interactions and Fracture Toughness of Basalt Fiber-Reinforced Epoxy Composites

2020 ◽  
Vol 20 (11) ◽  
pp. 6760-6767
Author(s):  
Seong Hwang Kim ◽  
Soo-Jin Park
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Graphene Oxide ◽  
High Performance ◽  
Basalt Fiber ◽  
Superior Performance ◽  
Microstructured Fibers ◽  
Multi Scale ◽  
Fundamental Understanding ◽  
Interlaminar Shear

Multiscale hierarchy is a promising chemical approach that provides superior performance in syner-gistically integrated microstructured fibers and nanostructured materials in composite applications. The main purpose of this work was to introduce graphene oxide (GO) between an epoxy matrix and basalt fibers to improve mechanical properties by enhancing interfacial adhesion. The composites were reinforced with various concentrations of GO. For all of the fabricated composites, the optimum GO content was found to be 0.5 wt%, which improved the interlaminar shear strength and fracture toughness by 66.2% and 86.1%, respectively, compared with those of neat composites. We observed a direct linear relationship between fracture toughness and certain surface free energy. In addition, the fracture toughness mechanisms were illustrated using a crack theory based on morphology analyses of fracture surfaces. Such an effort could accelerate the conversion of multi-scale composites into high-performance materials and provide rational guidance and fundamental understanding toward realizing the theoretical limits of mechanical properties.

ARMCO PH 13-8Mo

Alloy Digest ◽  
1990 ◽  
Vol 39 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stress Corrosion ◽  
Tensile Properties ◽  
High Performance ◽  
High Strength ◽  
Heat Treating ◽  
Temperature Performance

Abstract ARMCO PH 13-8Mo is designed for high-performance applications requiring high strength coupled with excellent resistance to corrosion and stress corrosion. It has excellent toughness, good transverse properties and excellent forgeability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-224. Producer or source: Baltimore Specialty Steels Corporation. Originally published May 1969, revised February 1990.

BETHLEHEM LUKENS PLATE HPS-70W

Alloy Digest ◽  
2000 ◽  
Vol 49 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Tensile Properties ◽  
High Performance ◽  
Iron And Steel ◽  
Cooperative Agreement ◽  
Federal Highway ◽  
High Performance Steel ◽  
Department Of The Navy ◽  
Steel Institute

Abstract BETHLEHEM LUKENS PLATE HPS-70W is a high-performance steel (HPS) developed through a cooperative agreement among the Federal Highway Administration (FHWA), the American Iron and Steel Institute (AISI), and the Department of the Navy. This steel is an improved version of ASTM A 709 grade 70W. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SA-506. Producer or source: Bethlehem Lukens Plate.

OUTOKUMPU TYPE 630

Alloy Digest ◽  
2016 ◽  
Vol 65 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
High Performance ◽  
High Strength ◽  
Heat Treating ◽  
304 Stainless Steel ◽  
Type 304 ◽  
Type 304 Stainless Steel

Abstract Outokumpu Type 630 is a martensitic age hardenable alloy of composition 17Cr-4Ni. The alloy has high strength and corrosion resistance similar to that of Type 304 stainless steel. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1238. Producer or source: Outokumpu High Performance Stainless.

VANADIS 4

Alloy Digest ◽  
1991 ◽  
Vol 40 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Powder Metallurgy ◽  
Physical Properties ◽  
Tool Steel ◽  
High Performance ◽  
Cold Work ◽  
Heat Treating ◽  
Good Combination ◽  
Bend Strength ◽  
Cold Work Tool Steel

Abstract VANADIS 4 is a high performance cold work tool steel made by powder metallurgy. It offers an extremely good combination of resistance and toughness for high performance tools. This datasheet provides information on composition, physical properties, hardness, elasticity, and bend strength as well as fracture toughness. It also includes information on heat treating and machining. Filing Code: TS-506. Producer or source: Uddeholm Corporation.

CHASSIS DESIGN & PERFORMANCE ANALYSIS FOR THE EUROPEAN EXOMARS ROVER

2005 ◽  
Vol 29 (4) ◽  
pp. 507-517
Author(s):  
Alex Ellery ◽  
Lutz Richter ◽  
Reinhold Bertrand
Keyword(s):  
Performance Analysis ◽  
Weight Distribution ◽  
High Performance ◽  
High Mobility ◽  
Scientific Instrument ◽  
Equal Weight ◽  
Scientific Instruments ◽  
Design Issues ◽  
Martian Surface ◽  
Considerable Size

The European Space Agency’s (ESA) ExoMars rover has recently been subject to a Phase A study led by EADS Astrium, UK. This rover mission represents a highly ambitious venture in that the rover is of considerable size ~200+kg with high mobility carrying a highly complex scientific instrument suite (Pasteur) of up to 40 kg in mass devoted to exobiological investigation of the Martian surface and sub-surface. The chassis design has been a particular challenge given the inhospitable terrain on Mars and the need to traverse such terrain robustly in order to deliver the scientific instruments to science targets of exobiological interest, We present some of the results and design issues encountered during the Phase A study related to the chassis. In particular, we have focussed on the overall tractive performance of a number of candidate chassis designs and selected the RCL (Science & Technology Rover Company Ltd in Russian) concept C design as the baseline option in terms of high performance with minimal mechanical complexity overhead. This design is a six-wheeled double-rocker bogie design to provide springless suspension and maintain approximately equal weight distribution across each wheel.

Design of differential-mode bandpass filter with common-mode suppression using ring dielectric resonator

2016 ◽  
Vol 9 (5) ◽  
pp. 1029-1035 ◽  
Author(s):  
Jugul Kishor ◽  
Binod K. Kanaujia ◽  
Santanu Dwari ◽  
Ashwani Kumar
Keyword(s):  
Dielectric Resonator ◽  
High Performance ◽  
Bandpass Filter ◽  
Ring Resonator ◽  
Differential Mode ◽  
Common Mode ◽  
Mode Suppression ◽  
Transmission Zeros ◽  
System A ◽  
Good Agreement

Synthesis of differential-mode bandpass filter (BPF) with good common-mode suppression has been described and demonstrated on the basis of ring dielectric resonator (RDR) for high-performance communication system. A RDR with two pairs of feeding lines has been used to excite TE01δ-mode. This unique combination of feeding lines and the ring resonator creates a differential passband. Meanwhile, TM01δ-mode of the DR can also be excited to achieve common-mode rejection in the stopband. Transmission zeros are created in the lower and upper stopband to further improve the selectivity of the proposed BPF. A second-order differential BPF is designed, fabricated and its performance is measured to validate the concept. There is good agreement between simulated and measured results.

A SURVEY OF CHECKPOINT/RESTART TECHNIQUES ON DISTRIBUTED MEMORY SYSTEMS

2013 ◽  
Vol 23 (04) ◽  
pp. 1340011 ◽  
Author(s):  
FAISAL SHAHZAD ◽  
MARKUS WITTMANN ◽  
MORITZ KREUTZER ◽  
THOMAS ZEISER ◽  
GEORG HAGER ◽  
...  
Keyword(s):  
High Performance ◽  
Building Blocks ◽  
Memory Systems ◽  
Time To Failure ◽  
Flow Solver ◽  
The Road ◽  
System A ◽  
Node Level ◽  
Mean Time ◽  
Performance Computing

The road to exascale computing poses many challenges for the High Performance Computing (HPC) community. Each step on the exascale path is mainly the result of a higher level of parallelism of the basic building blocks (i.e., CPUs, memory units, networking components, etc.). The reliability of each of these basic components does not increase at the same rate as the rate of hardware parallelism. This results in a reduction of the mean time to failure (MTTF) of the whole system. A fault tolerance environment is thus indispensable to run large applications on such clusters. Checkpoint/Restart (C/R) is the classic and most popular method to minimize failure damage. Its ease of implementation makes it useful, but typically it introduces significant overhead to the application. Several efforts have been made to reduce the C/R overhead. In this paper we compare various C/R techniques for their overheads by implementing them on two different categories of applications. These approaches are based on parallel-file-system (PFS)-level checkpoints (synchronous/asynchronous) and node-level checkpoints. We utilize the Scalable Checkpoint/Restart (SCR) library for the comparison of node-level checkpoints. For asynchronous PFS-level checkpoints, we use the Damaris library, the SCR asynchronous feature, and application-based checkpointing via dedicated threads. Our baseline for overhead comparison is the naïve application-based synchronous PFS-level checkpointing method. A 3D lattice-Boltzmann (LBM) flow solver and a Lanczos eigenvalue solver are used as prototypical applications in which all the techniques considered here may be applied.

scholarly journals Return Flight

1999 ◽  
Vol 121 (12) ◽  
pp. 62-64 ◽  
Author(s):  
Peggy Chalmers
Keyword(s):  
Flight Control ◽  
High Performance ◽  
Development Work ◽  
Flight Control System ◽  
Complex Interactions ◽  
System A ◽  
Physical Testing ◽  
Fluid Properties ◽  
Computational Fluid Dynamics Cfd ◽  
Thrust Control

This article focuses on the fact that using computational fluid dynamics (CFD) and design of experiments (DOE) software, researchers are in pursuit of aircraft fluidics thrust control without moving component parts. Fluidics’ performance is dictated by complex interactions among approximately two dozen geometric and fluid properties. These complex interactions probably proved overwhelming to early researchers seeking a stable, reliable rocket flight control system. A major advantage of DOE is that it allows all the parameters to vary simultaneously. A single permutation, on the other hand, varies one parameter at a time and cannot deal with interactions among the fixed parameters. There is still more development work to be done, but indications are that CFD and DOE are leading Lockheed Martin to a promising design. Physical testing reinforces the belief that a fluidic nozzle can achieve the performance levels required. The technology that never got off the ground in the early rocket era may find itself flying high in the next generation of high-performance tactical aircraft.

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