Objectives, results and works performed
An interlocking block with corrugated faces, can be seen as a main body with some projections on its faces called locks. These blocks may slide with respect to each other in one direction, when the joint frictional resistance is not enough. Also, if the locks and the main body are rigid enough, the block can fail in another direction, when the locks lose their connection with the main body. I.e. the mechanical behaviour of an interlocking joint not only depends on the frictional properties of the contacts between two blocks, but also on the mechanical properties of the assumed cohesive contact between each lock and the main body.
- First, SiDMACIB studied these mechanical properties and recorded the ultimate torsion-shear resistances of the contact subjected to the tangential force with different eccentricities with respect to the contact centroid, using numerical, analytical and experimental approaches. The analytical approach is an extension to the concave, convex and corrected concave formulations. The numerical approach is based on the discrete element method using 3DEC. The experimental investigation is a novel physical test to study the torsion-shear behaviour of interlocking joints as an alternative to the European Standard test.
- Then, the static problem of limit analysis (one of the main classical methods to analyse masonry structures) was extended to the interlocking joints with orthotropic sliding behaviour and validated using discrete element method. In this approach, the assemblage stress state is abstracted to the internal forces at some contact points distributed on interlocking joints. Several point distributions were tested to find the most realistic option.
- Reformulating the static problem, a method was developed to measure the infeasibility of a model due to the sliding valid range violation (sliding infeasibility). The method identifies the internal forces within and outside the mechanical valid ranges and takes their value to measure the sliding infeasibility in a model.
- A shape optimization was developed that first measures the sliding infeasibility of an interlocking model, and then automatically changes the designated geometric parameters of interlocking joints to minimize the measured infeasibility and find the structurally valid assemblage.
- An assemblability method was developed to check if the designed interlocking blocks can be assembled on the other blocks in contact. Choosing the wrong shape for the interlocking joints can immobilize a block in all directions. Adopting the Non-Directional Blocking Graph (NDBG), a simplified geometric analysis was formulated to check if the designed joints are assemblable.
- An open source Rhino-Grasshopper plugin was developed to model interlocking single layer shells with arbitrary shapes, with stacked or running bond pattern and with the possibility of modelling openings inside the shell. The plugin checks structural validity of the model, measures its infeasibility, and finds the optimal joint shape minimizing the infeasibility.
Dissemination and exploitation
SiDMACIB has been disseminated by nine peer reviewed journal and conference papers in the field of Structural Engineering and Computational Design. It was also presented in eight international conferences and workshops, with access to the experts both from academia and industry. All the papers, posters, and presentations are available on the Zenodo repository.
The SiDMACIB open-source GH plugin is available on the GitHub and Zenodo repository.
Furthermore, SiDMACIB concepts were introduced to the non-expert audiences in several outreach events held in Naples, a Radio interview, SiDMACIB official webpage and a Facebook page. The related flyers, videos and posters are available on the Zenodo repository.
