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Inestabilidades de fractura dinámica debido a la hiperelasticidad local en las puntas de las grietas
Markus J Buehler1, Huajian Gao
1Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 1-272, Cambridge, Massachusetts 02139, USA. mbuehler@MIT.EDU
Nature
|January 20, 2006
Resumen
La inestabilidad dinámica de los materiales frágiles hace que la superficie de la fractura se endurezca a medida que aumenta la velocidad de las grietas. La hiperelasticidad, o comportamiento no lineal de tensión-tensión, rige esta inestabilidad, explicando los fenómenos de propagación de grietas.
Área de la Ciencia:
- Mecánica de los Sólidos Mecánica de los Sólidos
- Ciencia de los materiales Ciencia de los materiales.
- Física computacional es la física computacional.
Sus antecedentes:
- La propagación de grietas en materiales frágiles exhibe inestabilidades dinámicas que conducen al áspero de la superficie.
- Los fenómenos observados incluyen superficies de fractura de espejo, niebla y hackle a velocidades crecientes de grietas.
- Las teorías de fractura existentes a menudo pasan por alto la relación no lineal de tensión y tensión (hiperelasticidad) cerca de las puntas de las grietas.
Objetivo del estudio:
- Investigar el papel de la hiperelasticidad en el inicio de la inestabilidad dinámica durante la propagación de las grietas.
- Desarrollar un modelo generalizado que explique la competencia de los mecanismos que controlan las inestabilidades de las grietas.
- Proporcionar información sobre controvertidos hallazgos experimentales y computacionales en la mecánica de las fracturas.
Principales métodos:
- Utilizó simulaciones atomistas masivas, paralelas y a gran escala.
- Empleó un modelo de material que permite una transición del comportamiento elástico lineal al comportamiento no lineal.
- Desarrolló un modelo generalizado para el inicio de la inestabilidad de la grieta.
Principales resultados:
- Se demostró que la hiperelasticidad es un factor determinante en el inicio de la inestabilidad dinámica.
- Identificó el inicio de la inestabilidad como una competencia entre el campo de tensión y los mecanismos de flujo de energía.
- Las simulaciones revelaron que las inestabilidades son intrínsecas a la fractura dinámica.
Conclusiones:
- La hiperelasticidad es crucial para comprender las inestabilidades de propagación de grietas.
- El modelo generalizado ofrece un marco para analizar la morfología de la superficie de la fractura.
- Los hallazgos concilian observaciones experimentales y computacionales dispares en la fractura frágil.
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