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Mark Hobbs

PhD updates

28/11/18 Project Update

November 28, 2018

The first year has been used to investigate the modelling of prismatic reinforced concrete members with peridynamics. A bond-based peridynamic analysis code has been developed and validated for simple problems. The existing literature on the computational modelling of reinforced concrete with peridynamics is limited to simple problems, and validation is mostly through qualitative visual evaluation of fracture behaviour. The work to date provides basic quantitative assessments by benchmarking simulations against codified design methods and commercial finite element analysis software.

The developed analysis code provides good predictions of the failure behaviour and load for prismatic reinforced concrete beams. The failure mode predicted by the analysis code and Eurocode 2 match for all test cases. For beams exhibiting a typical flexural failure, the predicted failure load was within +8% of the failure load predicted by Eurocode 2. Further research is needed on the validity of the predicted failure loads for beams exhibiting shear failure. In one test case, the predicted shear strength was 2.35 times higher than the value predicted by Eurocode 2. It is possible that Eurocode 2 provides highly conservative values of shear strength in some instances. The work to date has only considered a limited range of simple structural members. A much wider range of problems must be considered to investigate the generality and validity of the peridynamic theory.

09/02/18 Project Update

February 09, 2018

Project Update

 

The first months of the PhD have been dedicated to understanding the peridynamic theory and exploring the literature. Existing applications and limitations of peridynamic theory have been studied, and a number of simple peridynamic models have been developed in MATLAB for the analysis of specific problems. 2D and 3D problems have been simulated, including; 2D plates in tension and compression, and 3D blocks in tension and compression. Damage has been incorporated into the 2D analysis code and the cracking behaviour of a plate in tension and a cantilever in bending have been simulated (see attached figures).

Present work is investigating the inclusion of steel reinforcing bars within the analysis model. The models will be validated against test data available in the literature. Further work includes reviewing the literature and theory of topology optimisation. By combining topology optimisation methods with peridynamic theory, it might be possible to design optimised reinforced concrete structures that minimise material usage and increase utilisation factors. Peridynamic simulations are computationally expensive and parallel processing will be utilised to reduce cost. 

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