Structured cellular structures are nowadays printed using additive manufacturing methods like powder bed fusion. The relative density of the cellular structures has a big role in the suitability of a lattice for printing due to the minimum printable radius constraint and powder being trapped inside an inclusion. In this work, the theoretical limits of the printable range of relative density of different lattice types are found based on the cell size using computer methods by leaving other process parameters for further research as the current parameters are the most basic ones. The results are approximated using simple polynomials to enable practical usage.

Mechanical components are commonly fastened together using bolts. In many applications, they are subjected to impact loads during their service life. Their response and failure behaviour under these conditions needs to be known for their safe use. The objective of this study was to develop computationally efficient and accurate finite element models for bolted joints under impact loading. First, a three-dimensional detailed finite element model for a bolted joint was developed using solid elements. With this full modelling, the aim was to simulate the physics of the impact event as accurately as possible without any concern about computational cost. In the design of mechanical structures containing numerous fastening elements, use of detailed models is not practicable, because the computational cost of the analysis dramatically increases with the increased number of complex interacting parts. Instead, simplified models that only account for dominating effects should be utilized so that the analysis time can be significantly reduced without compromising the level of accuracy. Accordingly, a number of simplified finite element bolt models were developed and then compared with the full model with regard to the solution accuracy and computational cost to select the most representative and cost-effective simplified model.

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