Researchers from RMIT's Rheology and Materials Characterisation Laboratory have collaborated with Unipod to improve quality standards in the building industry.
The use of waffle pods, which are made from recycled polystyrene, has been continuously expanding in Australia since the mid-1980s and now constitutes a majority part of total slab floor construction for new homes, extensions or commercial industrial buildings.
In this method, concrete is poured on and around a series of pods laid in a grid above the ground rather than on to foundations dug into the soil, allowing for an insulating layer between the structure and the ground to be formed.
It also allows for more accurate concrete specification, reduces waste and provides a substantial boost to building site efficiency.
In addition, the method has minimal impact on the environment as there is less soil disturbance, and no excavated rubble from trenches to dispose of and air pockets created by the pods.
However, there is no current Australian standard for testing the waffle pods' structural integrity.
Professor Mike Xie, Dr Muthu Pannirselvam and Dr Shanqing Xu from the RMIT Centre for Innovative Structures and Materials collaborated with Unipod, a leading Victorian manufacturer of waffle pods, on a research project to develop an information and communications technology (ICT) application for the structural design of waffle pods.
"They were interested in developing a reliable impact test procedure for their product," Pannirselvam explained.
"We looked at replacing their existing design method of trial and error where no systematic optimisation is carried out with a Bi-directional Evolutionary Structural Optimisation (BESO) based technology which includes sensitivity analysis, a filter scheme and procedure for removing and adding materials.
"The benefits of the structural optimisation design are more than just the simplification of the design process and production lines but it is more than that, it actually minimises the structural volume while maintaining or enhancing its impact strength and weight and also improves the durability of the product."
Unipod used this optimised waffle pod design to manufacture a prototype moulding tool which was drop tested in the RMIT Rheology and Materials Characterisation Laboratory.
The next stage was to develop a user friendly interface by linking the BESO algorithm to a large commercial finite element modelling software with the capacity to produce appropriate topological designs for specific applications.
It is anticipated that the application module becomes a standard design tool for building professionals in Australia.
Unipod General Manager Peter Sheehan said poor quality pods could cause major construction failures and safety problems, as described in a promotional Youtube video.
"Using this design method will enhance our winning formula of providing a stronger, better value product and a more responsive and flexible solution to waffle pod supply," he said.
"We enjoyed our collaboration with RMIT and found that the skill, expertise and willingness to engage with industry was at a high level."
RMIT has extended its collaboration with Unipod to further develop the new pod design as part of a project funded by the Business Victoria Technology Voucher Program.
Story: Petra van Nieuwenhoven