Project Masc
(Modulo Autoportante di Struttura Cellulare)

Aldo Cella, PhD
CASoftware

Objective
The objective of Project MASC is to produce:
Optimal Design;
Experimental Validations;
Automated Manifacturing;
for the prototype of a self-bearing steel slab spanning (5 x5) m, gross dept 20 cm, built with cellular modules, and able to sustain large pressures (see Fig. 1).

Optimal Design
The Project is based on the features of the Cellular Algorithms Software (CASoft Ref [3]), that currently computes
the optimal stiffness of the members;
the weld parameters that produce 'safe' welds, when the welds are executed under the Protocols for Quality Welds (see Ref [1]).
Figs (2,3) show the computed max stresses in the upper and in the lower plates, under a standard service load:
smax = syield, in the upper plates, for local pressure;
smax = syield/10, in the lower plates, for bending of the ribs.
In the upper plates, the welds are subjected to bending; the parameters for bent welded joints have been already qualified in project WAM (see Ref [2]), leading to: factors = 1.0.

Experimental Validations
In the lower plates, the max stresses are low, because of the high stiffness of the cellular configuration. There is room for increasing further the service load. The welds, though, operate now under shear, and their strength needs to be validated by new experiments, repeating the procedures of project WAM.
NOTE 1: the welding models produced by CASoft with the Application Virtual Welding show a high scalability of the results; that leads to a substantial reduction in the number of experimental tests.
NOTE 2: the experimental tests, when made in parallel with the computational models, require far less instrumentation, because the computational model clearly indicates the locations where to make the cross checks.

Automated Manufacturing CASoft holds in store, for all the structural members:
the detailed geometry;
the plate thickness;

From these data the code can further derive, for all the welded joints:
the position and the geometry of the welded rods;
the type of joint (on bend, on shear);
the weld parameters, derived from the Quality Protocols;
Now, all these these data can be fed directly to the welding robots, closing the loop of design/manifacturing with a total automation.

Now Project MASC can be cast as Smart Production, fully within the context of the standard INDUSTRY 4.0 : the 4th Industrial Revolution.

References

• Progetto WAM
  Test di qualificazione: Specifiche Tecniche
  Ansaldo Nucleare, C.S.S.N., CASoft
• Misura di Temperature, Deformazioni e Tensioni nella Saldatura di Piastre (“Saldatura Virtuale”)
  Relazione LMT/0010/2016
  CSSN – 3° Reparto Tecnico Scientifico
• Cellular Algorithms:
  An Expert System for Analysis and Design in MCAE
  Presented at the World Engineering Forum, Rome 2017

Fig. 1 - Geometry of the cellular structure prototyping a steel self-bearing slab sizing (5 *5) m in plan, deep 20 cm.

Fig. 2 - Distribution of max stresses on the upper surface

Fig. 3 - Distribution of max stresses on the lower surface.