School of Civil, Environmental and Mining Engineering

Postgraduate research

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Current and completed research by our postgraduate students.

Contact

Mostafa Attar Khorassani

Phone: (+61 8) 6488 2446


Start date

Aug 2011

Submission date

Aug 2015

Mostafa Attar Khorassani

Thesis

The implementation of lattice spring model for static and dynamic analysis of damaged structures

Summary

A novel discrete method will be presented for static and dynamic analysis of damaged beam-like structures. Utilising the lattice spring model (LSM), the continuum is represented as a network of mass-springs (mass-spring-dashpots if the dissipation effects are considered). Two types of damages are investigated in this research: (A) damages that do not influence the linearity (smoothness) of the problem (i.e. the system is linear with the assumption of elastic behaviour of the structure in the range of small deformation theory), such as open edge cracks, (B) damages that change the smooth (linear) character of the system, even though the structural elastic behaviour is assumed to remain in the range of small deformation theory, such as breathing (bilinear) edge cracks, or damaged foundations. The presence of the edge crack in type (A) can be modelled by increasing the flexibility of the connecting spring at the micro-level in the location of the crack (using an additional linear spring to be combined in series with the LSM spring) to observe the effects of the damage in the mechanical behaviour of the structure at macro-level. In type (B), the non-smooth effects of the breathing crack (or the damaged foundation) can be represented by the application of Heaviside step function and one-way springs. The proposed method can be used to obtain static and dynamic response of the structure under different types of loading.

Why my research is important

What is the LSM (Lattice Spring Model)?

The LSM is a tool to solve problems of the continuum elasticity (including static and dynamic problems). In the LSM, the materials are discretised into a system of discrete units (e.g. rigid particles) interacting via springs. The particle distribution can be regular (periodic) or random. The spring properties in microstructure scale define the macro-mechanical properties of the matter. Due to the discrete nature of the LSM, it is a very appropriate method to reflect the microstructural properties of the matters. It is also a very suitable tool for failure and fracture simulations of solids at the continuous level which can be captured by simply removing the connecting elements (or increasing the flexibility of the connecting elements) at the micro-discontinuous level that exceeds the strength of the matter.


 

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