Tennant Co. is implementing computer-aided engineering to predict how its rotational molded parts will perform on its industrial and commercial floor cleaning equipment, an engineer reported.
Chuck Milton, principal engineer, said Tennant began its move to ``predictive engineering'' in 2002. The goal is to standardize the use of CAE as part of the normal design process for all new products. The CAE focuses on load-bearing structures.
The firm also wants to train all of its engineers to perform basic CAE on their own parts and subassemblies. CAE specialists will do more-complex analyses.
Minneapolis-based Tennant generates sales of nearly $500 million from floor cleaning machinery and street maintenance equipment.
Tennant Commercial, its seven-machine rotomolding operation, is based in Holland, Mich.
The company molds some large parts. At the Rotational Molding by Design Conference in Cleveland, Milton gave a case study of CAE on a big tank for a ride-on floor cleaner. The tank holds water and detergent vacuumed up from the floor, so the engineers wanted to test the initial design for its behavior under vacuum pressure, including displacement of the walls, fatigue stress and deflection strength.
The engineers built a finite element model, then applied vacuum stress to the sides. The CAE system depicted, with color-coded areas, various levels of displacement of the walls. Milton sent the CAE drawing back to the designer, and they moved some ribs, added an external stiffening plate and changed blend sizes.
After the tank was molded, it underwent extensive physical testing to prove the CAE prediction was accurate.