In South Africa where the unemployment is immense, Small Micro and Medium enterprises (SMMEs) provide more than half of all job opportunities. Furntech, a non-profit organisation that works with vocational training and incubation within the furniture manufacturing sector in South Africa, wants to expand their testing laboratory with a machine to test mattresses according to local standards. The aim of this project is to develop a machine design to test innerspring mattresses by using product development methodology. Observations, interviews, and visits at companies in the furniture manufacturing sector is conducted to understand the needs from the user- and mechanical aspects. Existing and required additional parts to support the functionality for the test bedding machine has been evaluated by calculations and simulations by using for example ABAQUS and JACK. A design is produced that meets the local standards by developing the existing table test machine in Furntech’s laboratory and is presented in a CAD-model. A scissor lift controls the vertical adjustment of the platform and an electric ball screw cylinder controls the compression of the mattresses. Instruction manuals, a graphical interface design, flowcharts and drawings of some of the parts has also been produced.

The natural variation of strength properties within brittle materials leads to size effect, a well-known phenomenon whereby the mean strength of a material is observed to decrease as the stressed volume increases. An important implication of size effect is that size adjustment parameters must be incorporated into multi-axial constitutive and failure models used in numerical simulations to predict material response to loading. This experimental study seeks to verify and quantify the presence of depth effect under shear failure in the orthotropic principal material directions of parallel strand lumber (PSL) and laminated veneer lumber (LVL). Torsion tests have been performed on specimens of fixed length and differing cross section to get a pure shear failure, by using a Universal Test Machine. The experimental results indicate that there is no depth effect for LVL from torsional shear stresses. PSL testing was limited to one size, and depth effect was not evaluated. A finite element model was built to simulate the torsional test for the 44x140mm LVL specimen. Comparing the experimental test results and the simulation results, the model provided an accurate prediction of the torsional test for Structural Composite Lumber.