The goal of this project was to create a lattice structure with high absorption mechanics for the purpose of using it in sports helmets and hopefully reducing the head trauma athletes are subject to. The structure itself was designed and analyzed in SOLIDWORKS through which FEA Static and Drop tests were performed. The main parameters that were measured are the displacement of the material under load and additionally the vertical displacement once the material reached a fatigued state. All results of the design project can be seen below and the final product looked like this:
Originally the part was designed in SOLIDWORKS through which we ran multiple static tests. In addition, once the structure was printed dynamic testing was performed. The material was pre-determined as TPU because it was material used in the 3D printers in the laboratory. For the static test the structure was subject to 50N static load which was applied normal to the top face of the structure. A detailed representation of the stress distribution of the lattice as well as a graph of the deformation of the material can be seen below:
It can be noted that the maximum stress that the structure was subject to was 1.421 MPa which is well below the 15,600 MPa yield stress of the material. Furthermore, the material begins to deform significantly under a static load of over 60 N.
The dynamic testing involved dropping a 2.4 kg mass onto the structure from a height of 50 mm. Using an accelerometer and WitMotion software, the acceleration of the mass when impacting the structure was determined. This allowed us to determine the displacement of the structure and the rebound height. A graph of the acceleration data can be seen below.
The results of the dynamic experience were in terms of the maximum acceleration at the point of impact. Three separate trials were run under the same conditions to obtain the most accurate data possible.
For a more detailed description of the results of the test feel free to read the full report. It outlines in much greater detail the implications of all the testing. However, to sum up the results, the lattice structure exceeded our expectations when it came to its strength and absorption quality.