The Influence of the Matrix-Aggregate Bond on the Strength and Brittleness of Concrete

1987 ◽  
Vol 114 ◽  
Author(s):  
Wu Keru ◽  
Zhou Jianhua
Keyword(s):  
Energy Dissipation ◽  
Crack Propagation ◽  
Aggregate Size ◽  
Brittleness Index ◽  
Interfacial Bond ◽  
Rational Distribution ◽  
The Matrix

ABSTRACTIn this paper, the influence of the matrix-aggregate bond on the strength and brittleness of concrete is studied. Six different matrixaggregate interfaces are used to evaluate the interfacial bond capability. The results obtained on the strength and brittleness index of concrete show that strengthening and toughening of concrete can be obtained simultaneously, if the interfacial bonds are changes so that they conform to a rational distribution according to aggregate size. These results are discussed in terms of the energy dissipation and crack propagation during failure of concrete.

Whisker-Reinforced Ceramic Matrix Composites

MRS Bulletin ◽  
1987 ◽  
Vol 12 (7) ◽  
pp. 66-72 ◽  
Author(s):  
J. Homeny ◽  
W.L. Vaughn
Keyword(s):  
High Temperature ◽  
Energy Dissipation ◽  
Mechanical Performance ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Mechanical Reliability ◽  
Interfacial Bond ◽  
High Fracture ◽  
The Matrix

Whisker-reinforced ceramic matrix composites have recently received a great deal of attention for applications as high temperature structural materials in, for example, advanced heat engines and high temperature energy conversion systems. For applications requiring mechanical reliability, the improvements that can be realized in fracture strength and fracture toughness are of great interest. Of particular importance for optimizing the mechanical reliability of these composites is the effect of the whisker/matrix interfacial characteristics on the strengthening and toughening mechanisms. Whisker reinforcements are primarily utilized to prevent catastrophic brittle failure by providing processes that dissipate energy during crack propagation. The degree of energy dissipation depends on the nature of the whisker/matrix interface, which can be controlled largely by the matrix chemistry, the whisker surface chemistry, and the processing parameters.It is generally believed that a strong interfacial bond results in a composite exhibiting brittle behavior. These composites usually have good fracture strengths but low fracture toughnesses. If the interfacial bond is weak, the composite will not fail in a catastrophic manner due to the activation of various energy dissipation processes. These latter composites tend to have high fracture toughnesses and low fracture strengths. Generally, the interface should be strong enough to transfer the load from the matrix to the whiskers, but weak enough to fail preferentially prior to failure. Thus, local damage occurs without catastrophic failure. It is therefore necessary to control the interfacial chemistry and bonding in order to optimize the overall mechanical performance of the composites.

Experimental Study of Steel Fibre Bridging Action on Crack Propagation in Fibre Reinforced Concrete

2006 ◽  
Vol 324-325 ◽  
pp. 1067-1070 ◽  
Author(s):  
Zhi Hong Xu ◽  
Wen Yin Liang ◽  
Yu Jing Liang
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
Steel Fibre ◽  
Fibre Reinforced Concrete ◽  
Interfacial Bond ◽  
Cycle Number ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete ◽  
Fibre Bridging ◽  
The Matrix

In this paper the bridging action of steel fibres on the model I crack propagation has been studied experimentally for steel fibre reinforced concrete (FRC). From the experimental results three main conclusions are obtained. First, the bridging action increases with the number of the steel fibres across the crack surface and the stress intensity factor near the crack tip decreases thereby. Second, bridging action increases with the strength of the matrix because the matrix with higher strength can provide stronger interfacial bond with steel fibres. Third, the interfacial bonding gets damaged when the steel fibres under cyclic loads and the bridging action degrades with the cycle number.

scholarly journals Material parametrization of natural rubber based compound and characterization of crack propagation under consideration of dissipative effects

2021 ◽  
Author(s):  
Dan Pornhagen ◽  
Konrad Schneider ◽  
Markus Stommel
Keyword(s):  
Energy Dissipation ◽  
Crack Propagation ◽  
Natural Rubber ◽  
Experimental Tests ◽  
Material Behavior ◽  
Prony Series ◽  
Material Forces ◽  
Cracking Behavior ◽  
Dissipative Effects

AbstractMost concepts to characterize crack propagation were developed for elastic materials. When applying these methods to elastomers, the question is how the inherent energy dissipation of the material affects the cracking behavior. This contribution presents a numerical analysis of crack growth in natural rubber taking energy dissipation due to the visco-elastic material behavior into account. For this purpose, experimental tests were first carried out under different load conditions to parameterize a Prony series as well as a Bergström–Boyce model with the results. The parameterized Prony series was then used to perform numerical investigations with respect to the cracking behavior. Using the FE-software system ANSYS and the concept of material forces, the influence and proportion of the dissipative components were discussed.

The study of a fatigue crack propagation in titanium Grade 2 using analysis of energy dissipation and acoustic emission data

2019 ◽  
Vol 210 ◽  
pp. 312-319 ◽  
Author(s):  
A.N. Vshivkov ◽  
A. Yu. Iziumova ◽  
I.A. Panteleev ◽  
A.V. Ilinykh ◽  
V.E. Wildemann ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Energy Dissipation ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Emission Data ◽  
Titanium Grade

Mechanical stabilization for the control of frost heave

1985 ◽  
Vol 12 (4) ◽  
pp. 899-905 ◽  
Author(s):  
R. J. Kettle ◽  
E. Y. McCabe
Keyword(s):  
Coarse Aggregate ◽  
Aggregate Size ◽  
Individual Characteristics ◽  
Frost Heave ◽  
Freezing Process ◽  
Natural Soil ◽  
Soil Matrix ◽  
Mechanical Stabilization ◽  
The Matrix

This paper is concerned with the role of mechanical stabilization in controlling frost susceptibility. This has been assessed in terms of the heave, developed over a 250 h period, of cylindrical specimens subjected to the Transport and Road Research Laboratory (United Kingdom) frost heave test. The basic soil matrix consisted of a highly susceptible mixture of sand and ground chalk. Three types of coarse particle (slag, basalt, limestone) were used as the stabilizing agent, and these were each subdivided into two particle groups: 20−3.35 mm and 37.5−20 mm.The introduction of up to 50% of the selected coarse aggregates produced various non-frost-susceptible mixtures. The influence of the coarse aggregate was very dependent on aggregate type but less dependent on aggregate size. The data have been examined to assess the role of these coarser particles in the freezing process, including the effects of their individual characteristics. This clearly demonstrated the possibility of using mechanical stabilization to control frost susceptibility and this was supported by the results of additional tests on natural soil. Heaving pressures are also reported and are examined in relation to the amount of aggregate added, nature of the aggregate, and particle size. The addition of coarse aggregate to the matrix is shown to reduce the measured heaving pressures. Key words: frost heave, heaving pressure, granular materials, mechanical stabilization.

Study on Interior Fracture Property of High Strength Steel in Very High Cycle Regime

2012 ◽  
Vol 482-484 ◽  
pp. 1169-1175
Author(s):  
Ren Hao Jiang ◽  
Wei Li ◽  
Yan Ping Shi ◽  
Jiang He
Keyword(s):  
Crack Propagation ◽  
Fracture Property ◽  
Crack Nucleation ◽  
Fatigue Property ◽  
High Strength ◽  
Bearing Steel ◽  
Stable Crack Propagation ◽  
The Matrix ◽  
Fish Eye ◽  
Very High

Based on the fracture mechanics theory and fracture surface topography analysis (FRASTA) method, the interior fracture property of a bearing steel in very high cycle regime was studied by means of rotary bending fatigue test. As a result, this bearing steel represents the duplex S-N curves characteristic, where the interior inclusion-induced fracture is the predominant fracture mode in very high cycle regime. The rough granular bright facet (GBF) area corresponding to smaller inclusion is usually formed in the lifetime larger than 106 cycles, whose formation progress can be interpreted as the slow crack nucleation based on decohesion of spherical carbide from the matrix. The fatigue property in the fish-eye region outside of GBF can be interpreted as the stable crack propagation progress and that outside of fish-eye is instable crack propagation progress. The stress intensity factor ranges of GBF and fish-eye, ΔKGBF and ΔKfish-eye, can be regarded as the threshold values of controlling stable propagation and instable propagation of interior crack, respectively.

Calculation of contraction stresses in dental composites by analysis of crack propagation in the matrix surrounding a cavity

2009 ◽  
Vol 25 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Takatsugu Yamamoto ◽  
Jack L. Ferracane ◽  
Ronald L. Sakaguchi ◽  
Michael V. Swain
Keyword(s):  
Crack Propagation ◽  
Dental Composites ◽  
The Matrix

Shock attenuation mechanisms of magnetorheological elastomers absorbers: A theoretical analysis

2016 ◽  
Vol 51 (5) ◽  
pp. 721-730 ◽  
Author(s):  
Dingxin Leng ◽  
Xiaojie Wang ◽  
Lingyu Sun ◽  
Faramarz Gordaninejad
Keyword(s):  
Magnetic Field ◽  
Energy Dissipation ◽  
Variable Stiffness ◽  
Rubber Matrix ◽  
Interfacial Friction ◽  
Response Force ◽  
Shock Attenuation ◽  
Interfacial Bond ◽  
Magnetorheological Elastomers ◽  
Shock Absorbers

To predict the dynamic response of shock absorbers based on magnetorheological elastomers and investigate the contributions of various possible energy dissipation mechanisms, a modified four-parameter model of magnetorheological elastomers was proposed, which includes the viscoelastic characteristics of rubber matrix, the variable stiffness and damping property, and the interfacial bond conditions of magnetorheological elastomers under the applied magnetic field. The constitutive equations of magnetorheological elastomers were derived and all parameters were identified based on a published literature. It is theoretically demonstrated that the maximum response force under an impulse input could be attenuated approximately 30% when the magnetic field with 0.57 T is applied. Using the proposed theoretical model, it is shown that the energy dissipation mechanisms mainly come from the interfacial friction between particles and matrix, and the increment on stiffness and dynamic viscosity of the rubber matrix provides reverse contributions to the shock mitigation, while the interfacial bond stiffness has little influence on the response force amplitude. Hence, when magnetorheological elastomers are utilized in shock absorbers, it is suggested to take advantage of the interfacial friction energy.

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