Heavily loaded solar panel foot

BPO has helped Sunbeam with realising the plastic foot for the new Supra mounting system for solar panels on flat roofs. The plastic foot is used to transfer the weight and loads of the system onto the roof. The plastic foot must withstand these continuously applied loads and it must not fail due to deformation on the, often partially soft, surface.

The foot is made of recycled HDPE. Plastics like this are sensitive to creep. This means that the material, when loaded for a long period of time, acts in a different way than the initial properties that are indicated in the data sheets. That is why BPO uses its own custom-made material models that consider this for all its simulations.

The design of the Supra foot is analysed using FEM-simulations and the strength and stiffness of the geometry have been optimised. This way the design was improved to reduce the deformation and stress in the material at similar loads. The risk of problems in daily use are decreased significantly.

Simulations of foot, with and without steel profile

To function well, the foot must be flat and undeformed. The injection moulding of semicrystalline materials as HDPE can be a great challenge as internal stresses may create deformations. This so-called warpage can be predicted using injection moulding simulations. This way BPO has determined the optimal injection gate locations and production settings to get a minimal amount of deformation of the part.

The Supra system is currently in production and has already been installed at several locations. For more information also see sunbeam.solar/product/sunbeam-supra