The Theory of Critical Distances to Model the Short- to Long-crack Transition in Geological Materials Subjected to Mode I Static Loading

nterlaminar toughness of glass-epoxy laminates subjected to Mode I quasi static loading was investigated. The influence of reinforcement geometry on GIc was focused. Six different laminates reinforced with INTERGLAS 2/2 twill fabrics of three different areal densities and two strand orientations, θ, were tested. The considered fabric areal densities were 390g/m2, 280g/m2 and 163g/m2, and strand orientations θ=0°/90° and θ=±45°. For laminates with θ=±45° strand orientation a statistically significant difference in the means of the interlaminar toughness GIc was noticed for all three laminates i.e. reinforced with the fabrics of areal densities 163 g/m2 and 280 g/m2, and 390 g/m2. For laminates with strand orientation θ=0°/90° a significant difference in Gic means was noticed for laminates with fabrics of areal densities 163 g/m2 and 280 g/m2, and 280 g/m2 and 390 g/m2, only. For groups of laminates reinforced with a particular fabric type a statistically significant difference in the means of GIc was found each time when laminates differed in the strand arrangement θ regardless the way the GIc values were calculated. Fracture analysis done with the help of a SEM did not explained the observed differences in GIc values.

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Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154780 ◽

1989 ◽

Vol 47 ◽

pp. 562-563

Author(s):

Gyeung Ho Kim ◽

Mehmet Sarikaya ◽

D. L. Milius ◽

I. A. Aksay

Keyword(s):

Thin Film ◽

Mechanical Properties ◽

Fracture Toughness ◽

Static Loading ◽

Carbon Deposition ◽

Full Density ◽

Unique Combination ◽

Strong Component ◽

Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

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CREDO RADON UA – INFORMATION MODEL FOR CALCULATION OF ROAD CONSTRACTION

Avtoshliakhovyk Ukrayiny ◽

10.33868/0365-8392-2019-3-259-34-42 ◽

2019 ◽

pp. 34-42

Author(s):

Volodymyr Karedin ◽

Nadiya Pavlenko

Keyword(s):

Design Process ◽

Static Loading ◽

Computer Aided Design ◽

Experimental Studies ◽

Construction Materials ◽

Residual Deformation ◽

Road Construction ◽

Information Support ◽

Existing Structures ◽

Road Pavement

CREDO RADON UA software provides an automated calculation of the strength of the pavement structures of non-rigid and rigid types, as well as the calculation of the strengthening of existing structures. In the article, one can see the main features and functionality of the CREDO RADON UA software, the main points in the calculations according to the new regulations. Information support of the design process includes necessary databases, informational and helping materials that make up the full support of the pavement design process. The concept of CREDO RADON UA 1.0 software is made on the use of elasticity theory methods in calculations of initial information models of pavements. Performing optimization calculations, the roadwear in CREDO RADON UA is designed in such a way that no unacceptable residual deformation occurs under the influence of short-term dynamic or static loading in the working layer of the earth bed and in the structural layers during the lifetime of the structure. The calculation algorithms were made in accordance with the current regulatory documents of Ukraine. CREDO RADON UA software allows user to create information bases on road construction materials and vehicles as part of the traffic flow for calculations. The presented system of automated modeling makes it easier for the customer to control the quality of design solutions, to reasonably assign designs to layers of reinforcement, to quickly make comparisons of calculations of different designs for the optimal use of allocated funds. Prospects for further improvement of the program should be the results of theoretical and experimental studies on filling the databases, which are used as information support for automated design of road structures. Keywords: CREDO RADON UA, road, computer-aided design, repair project, road pavement, strengthening, construction, rigid pavement, elasticity module, a transport stream, calculation method, information support, dynamic or static loading.

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