Analysis of the grain/size dependence of the lower yield stress in steel

High fluidity concrete exhibits an excellent self-compacting property. However, the application of typical high-fluidity concrete is limited in the normal strength range (18~35 MPa) due to the large amount of binder. Therefore, it is important to solve these problems by adding a viscosity modifying agent (VMA) with a superplasticizer (PCE), which helps to improve the fluidity of the concrete. In addition, the rheology and stability of the concrete with VMA can be improved by preventing bleeding and segregation issues. Current studies focused on the physical phenomena of concrete such as the fluidity, rheological properties, and compressive strength of normal-strength, high-fluidity concrete (NSHFC) with different types of a polycarboxylate-based superplasticizer (NPCE). The obtained results suggested that the combinations of all-in-one polycarboxylate-based superplasticizers (NPCE) did not cause any cohesion or sedimentation even stored for a long time. The combination of three types of VMA showed the best fluidity (initial slump flow of 595~630 mm) without any segregation and bleeding, and the compressive strength at 28 days was also found to be the highest: 34–37 MPa. From these results, the combination of PCE (2.0%) + HPMC (0.3%) + WG (0.1%) + ST (0.1%) showed an 18% higher plastic viscosity and -4.4% lower yield stress than Plain.

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A Theory of the Grain Size Dependence of the Yield Stress in Face-Centered Cubic Alloys

Transactions of the Japan Institute of Metals ◽

10.2320/matertrans1960.16.17 ◽

1975 ◽

Vol 16 (1) ◽

pp. 17-27 ◽

Cited By ~ 18

Author(s):

Hideji Suzuki ◽

Kyôji Nakanishi

Keyword(s):

Grain Size ◽

Yield Stress ◽

Size Dependence ◽

Face Centered Cubic ◽

Face Centered

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On the Propagation of Lu¨ders Bands in Steel Strips

Journal of Applied Mechanics ◽

10.1115/1.1328348 ◽

2000 ◽

Vol 67 (4) ◽

pp. 645-654 ◽

Cited By ~ 48

Author(s):

S. Kyriakides ◽

J. E. Miller

Keyword(s):

Yield Stress ◽

Strain Level ◽

Finite Element Models ◽

Localized Deformation ◽

Lower Yield ◽

Lower Yield Stress ◽

Fine Grained ◽

Steel Strips ◽

Initiation And Propagation ◽

Transient Events

The initiation and propagation of Lu¨ders-type localized deformation in thin, fine grained steel strips in tension is studied through combined experimental and analytical efforts. Purely elastic deformation is terminated (upper yield stress) by localized deformation which tends to initiate along preferred directions. The strain level associated with this material instability is limited to two to five percent. When this strain level is achieved locally, the instability propagates via inclined fronts which separate coexisting regions of essentially elastic and plastically deformed materials. Under displacement controlled stretching, one or two fronts propagate in a steady-state manner (lower yield stress). The propagation of one and two fronts are simulated numerically using finite element models in which the material is modeled as a finitely deforming elastoplastic solid with an up-down-up nominal stress-strain response. The simulations capture the major events observed in the experiments such as the initiation process, the propagation of inclined fronts, kinking of the strip and the build up of moments, and the periodic straightening and moment reduction through transient events. This confirms that structural effects play a major role in the evolution of observed events. [S0021-8936(00)01604-4]

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216 Grain-Size Dependence of Yield Stress of Aluminum in Tortioin Test

The Proceedings of Conference of Chugoku-Shikoku Branch ◽

10.1299/jsmecs.2001.39.71 ◽

2001 ◽

Vol 2001.39 (0) ◽

pp. 71-72

Author(s):

Hiroshi MIURA ◽

Shigeru NAGAKI ◽

Ichiro SHIMIZU ◽

Kenji TEDUKA ◽

Takeji ABE

Keyword(s):

Grain Size ◽

Yield Stress ◽

Size Dependence

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