### Abstract

Every material changes its failure behavior under different loading rates, and this is the so-called rate dependency of materials. In particular, brittle and quasi-brittle materials show significant change of strength and strain capacity under different loading rates. Usually this phenomenon can be found experimentally, and this effect can be utilized in many engineering aspects. Thus, formulas based on experimental results have been adopted to predict material failure behavior under a given loading rate in engineering design. Most of the parameters are expressed through diagrams as functions of strain rate. Therefore, if the strain rates are assigned for a certain application of materials, the dynamic factors can be picked from the curve. The strength under the given loading rate can be defined as a factor which multiplies the strength under a quasi-static loading condition. However, this method depends on massive experimental works, and there is still a lack of understanding of fundamental behavior of the material failure characteristics. In this paper, the fundamental failure behavior of brittle material under different loading rates is observed using a numerical simulation based on the molecular dynamics analysis. A brittle material is modeled by numerous particles with a multi-scale analysis scheme. Each particle has interactions with the other particles with Lennard-Jones potential between particles. Sub-million particles are modeled for a simulation. Numerical simulations are performed with different loading rates in a direct tensile test on specimen with a notch. The loading rates are varied over a broad range which includes the stress wave velocity of the material. The trend of the strain capacity curve and crack propagation profile can be achieved from the simulations with various loading rates. The results will provide a detailed description of failure mechanism which changes with different strain rates.

Original language | English |
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Title of host publication | Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures |

Pages | 93-98 |

Number of pages | 6 |

Publication status | Published - 2007 Dec 1 |

Event | 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures - Catania, Italy Duration: 2007 Jun 17 → 2007 Jun 22 |

### Publication series

Name | Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures |
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Volume | 1 |

### Other

Other | 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures |
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Country | Italy |

City | Catania |

Period | 07/6/17 → 07/6/22 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Civil and Structural Engineering
- Mechanics of Materials
- Building and Construction

### Cite this

*Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures*(pp. 93-98). (Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures; Vol. 1).

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*Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures.*Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures, vol. 1, pp. 93-98, 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures, Catania, Italy, 07/6/17.

**Simulation of fracture at different loading rates using molecular dynamics.** / Kim, Jang Jay Ho; Lim, J.; Lim, Yun Mook.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

TY - GEN

T1 - Simulation of fracture at different loading rates using molecular dynamics

AU - Kim, Jang Jay Ho

AU - Lim, J.

AU - Lim, Yun Mook

PY - 2007/12/1

Y1 - 2007/12/1

N2 - Every material changes its failure behavior under different loading rates, and this is the so-called rate dependency of materials. In particular, brittle and quasi-brittle materials show significant change of strength and strain capacity under different loading rates. Usually this phenomenon can be found experimentally, and this effect can be utilized in many engineering aspects. Thus, formulas based on experimental results have been adopted to predict material failure behavior under a given loading rate in engineering design. Most of the parameters are expressed through diagrams as functions of strain rate. Therefore, if the strain rates are assigned for a certain application of materials, the dynamic factors can be picked from the curve. The strength under the given loading rate can be defined as a factor which multiplies the strength under a quasi-static loading condition. However, this method depends on massive experimental works, and there is still a lack of understanding of fundamental behavior of the material failure characteristics. In this paper, the fundamental failure behavior of brittle material under different loading rates is observed using a numerical simulation based on the molecular dynamics analysis. A brittle material is modeled by numerous particles with a multi-scale analysis scheme. Each particle has interactions with the other particles with Lennard-Jones potential between particles. Sub-million particles are modeled for a simulation. Numerical simulations are performed with different loading rates in a direct tensile test on specimen with a notch. The loading rates are varied over a broad range which includes the stress wave velocity of the material. The trend of the strain capacity curve and crack propagation profile can be achieved from the simulations with various loading rates. The results will provide a detailed description of failure mechanism which changes with different strain rates.

AB - Every material changes its failure behavior under different loading rates, and this is the so-called rate dependency of materials. In particular, brittle and quasi-brittle materials show significant change of strength and strain capacity under different loading rates. Usually this phenomenon can be found experimentally, and this effect can be utilized in many engineering aspects. Thus, formulas based on experimental results have been adopted to predict material failure behavior under a given loading rate in engineering design. Most of the parameters are expressed through diagrams as functions of strain rate. Therefore, if the strain rates are assigned for a certain application of materials, the dynamic factors can be picked from the curve. The strength under the given loading rate can be defined as a factor which multiplies the strength under a quasi-static loading condition. However, this method depends on massive experimental works, and there is still a lack of understanding of fundamental behavior of the material failure characteristics. In this paper, the fundamental failure behavior of brittle material under different loading rates is observed using a numerical simulation based on the molecular dynamics analysis. A brittle material is modeled by numerous particles with a multi-scale analysis scheme. Each particle has interactions with the other particles with Lennard-Jones potential between particles. Sub-million particles are modeled for a simulation. Numerical simulations are performed with different loading rates in a direct tensile test on specimen with a notch. The loading rates are varied over a broad range which includes the stress wave velocity of the material. The trend of the strain capacity curve and crack propagation profile can be achieved from the simulations with various loading rates. The results will provide a detailed description of failure mechanism which changes with different strain rates.

UR - http://www.scopus.com/inward/record.url?scp=56349086466&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=56349086466&partnerID=8YFLogxK

M3 - Conference contribution

SN - 0415440653

SN - 9780415440653

T3 - Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures

SP - 93

EP - 98

BT - Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures - Fracture Mechanics of Concrete and Concrete Structures

ER -