Structural response analysis in time and frequency domain considering both ductility and strain rate effects under uniform and multiple-support earthquake excitations

AbstractThe interaction between an eccentric matrix crack and a circular inclusion in composites was investigated numerically to explore the strain rate effects on the crack deflection/penetration behavior at the matrix-inclusion interface. It is found, with the increase of strain rate, that there will occur in turn the crack deflection, the double-crack fracture and the crack penetration processes for a certain material. Moreover, both higher relative interfacial strength and smaller eccentric angles can redound to the crack penetration. Additionally, it is demonstrated that the strain rate effect on the composite strength is a local structural response characteristic rather than an intrinsic material property, which sounds in agreement with that proposed by previous authors.

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Integration of Viscoplastic Effects in a One-Dimensional Constitutive Model for Ground Response Analysis

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0717 ◽

2020 ◽

Author(s):

Samuel Yniesta ◽

Mallak Janati-Idrissi

Keyword(s):

Strain Rate ◽

Stress Component ◽

Response Analysis ◽

Shear Strain Rate ◽

Ground Response ◽

Ground Response Analysis ◽

Strain Rate Effects ◽

One Dimensional ◽

Rate Effects ◽

Modulus Reduction

During an earthquake, strain-rate effects affect both the stiffness and damping behaviour of soils, yet existing constitutive models for ground response analysis are typically formulated within a rate-independent framework. In this paper, a one-dimensional viscoplastic stress-strain model is presented to introduce strain rate effects in ground response analysis. Its constitutive equations are based on a model that uses a cubic spline fit of the modulus reduction curve and a coordinate transformation technique to match any input modulus reduction and damping curve. A viscous stress component is added to model the effect of strain rate on the mechanical behaviour of soils using a single input parameter. The model is able to reproduce the linear increase in shear strength with the logarithm of shear strain rate, and allows to introduce viscous effects in 1D ground response analysis with control over damping and modulus reduction behaviour. The model is implemented in a software for ground response analysis and used to predict the results of a centrifuge test modeling one-dimensional wave propagation. The results show that the model predicts accurately the amplification and attenuation of shear waves, in a context where strain rates impact significantly the response of the model.

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Strain Rate Effects on the Interaction between an Eccentric Matrix Crack and a Circular Inclusion in Composites under Dynamic Loadings

International Journal of Nonlinear Sciences and Numerical Simulation ◽

10.1515/ijnsns-2011-114 ◽

2012 ◽

Vol 13 (2) ◽

Author(s):

Lu-Guang Liu ◽

Zhuo-Cheng Ou ◽

Ai-Guo Pi ◽

Zhuo-Ping Duan ◽

Feng-Lei Huang

Keyword(s):

Strain Rate ◽

Structural Response ◽

Interfacial Strength ◽

Response Characteristic ◽

Circular Inclusion ◽

Crack Deflection ◽

Matrix Crack ◽

Strain Rate Effects ◽

Crack Penetration ◽

Rate Effects

AbstractThe interaction between an eccentric matrix crack and a circular inclusion in composites was investigated numerically to explore the strain rate effects on the crack deflection/penetration behavior at the matrix-inclusion interface. It is found, with the increase of strain rate, that there will occur in turn the crack deflection, the double-crack fracture and the crack penetration processes for a certain material. Moreover, both higher relative interfacial strength and smaller eccentric angles can redound to the crack penetration. Additionally, it is demonstrated that the strain rate effect on the composite strength is a local structural response characteristic rather than an intrinsic material property, which sounds in agreement with that proposed by previous authors.

Download Full-text