ON THE STRENGTH RELIABILITY OF STATISTICALLY HETEROGENEOUS MATERIALS WITH MICROSTRUCTURE AT DIVERSE SCALES

The probabilistic aspects of multiscale modeling of the fracture of heterogeneous structures are considered. An approach combining homogenization methods with phenomenological and numerical models of fracture mechanics is proposed to solve the problems of assessing the probabilities of destruction of structurally heterogeneous materials. A model of a generalized heterogeneous structure consisting of heterogeneous materials and regions of different scales containing cracks and crack-like defects is formulated. Linking of scales is carried out using kinematic conditions and multiscale principle of virtual forces. The probability of destruction is formulated as the conditional probability of successive nested fracture events of different scales. Cracks and crack-like defects are considered the main sources of fracture. The distribution of defects is represented in the form of Poisson ensembles. Critical stresses at the tops of cracks are described by the Weibull model. Analytical expressions for the fracture probabilities of multiscale heterogeneous structures with multilevel limit states are obtained. An approach based on a modified Monte Carlo method of statistical modeling is proposed to assess the fracture probabilities taking into account the real morphology of heterogeneous structures. A feature of the proposed method is the use of a three-level fracture scheme with numerical solution of the problems at the micro, meso and macro scales. The main variables are generalized forces of the crack propagation and crack growth resistance. Crack sizes are considered generalized coordinates. To reduce the dimensionality, the problem of fracture mechanics is reformulated into the problem of stability of a heterogeneous structure under load with variations of generalized coordinates and analysis of the virtual work of generalized forces. Expressions for estimating the fracture probabilities using a modified Monte Carlo method for multiscale heterogeneous structures are obtained. The prospects of using the developed approaches to assess the fracture probabilities and address the problems of risk analysis of heterogeneous structures are shown.

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A Fundamental Investigation into the Deformation and Failure Behavior of Heterogeneous Materials with the Aim of Developing Design Guidelines

10.21236/ada425797 ◽

2004 ◽

Author(s):

Krishnaswarmy Ravi-Chandar

Keyword(s):

Heterogeneous Materials ◽

Design Guidelines ◽

Failure Behavior ◽

Deformation And Failure ◽

Fundamental Investigation

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Microstructure and Mechanical Properties of Al-Mg-Si Similar Alloy Laminates Produced by Accumulative Roll Bonding

Materials ◽

10.3390/ma14154200 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4200

Author(s):

Zhigang Li ◽

Hao Jiang ◽

Minghui Wang ◽

Hongjie Jia ◽

Hongjiang Han ◽

...

Keyword(s):

Mechanical Properties ◽

Accumulative Roll Bonding ◽

Thin Sheet ◽

Heterogeneous Materials ◽

Thick Sheet ◽

Subsequent Aging ◽

Roll Bonding ◽

Roll Casting ◽

Promotive Effect ◽

Similar Materials

As the applications of heterogeneous materials expand, aluminum laminates of similar materials have attracted much attention due to their greater bonding strength and easier recycling. In this work, an alloy design strategy was developed based on accumulative roll bonding (ARB) to produce laminates from similar materials. Twin roll casting (TRC) sheets of the same composition but different cooling rates were used as the starting materials, and they were roll bonded up to three cycles at varying temperatures. EBSD showed that the two TRC sheets deformed in distinct ways during ARB processes at 300°C. Major recrystallizations were significant after the first cycle on the thin sheet and after the third cycle on the thick sheet. The sheets were subject to subsequent aging for better mechanical properties. TEM observations showed that the size and distribution of nano-precipitations were different between the two sheet sides. These nano-precipitations were found to significantly promote precipitation strengthening, and such a promotive effect was referred to as hetero-deformation induced (HDI) strengthening. Our work provides a new promising method to prepare laminated heterogeneous materials with similar alloy TRC sheets.

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