Discrete Dislocation Dynamics concerns the analysis of microplasticity in which the dislocations, a line defect in the crystallographic periodicity, are treated as separate moving entities inside an elastic continuum. This analysis at the mesoscale can give valuable insights in the nature of dislocations and the behaviour of macroscopic plasticity. Although an analytical solution for dislocations exist, special measures are to be taken for the solution of boundary value problems. In this thesis a Discrete Dislocation Dynamic model in a two-dimensional plane-strain formulation for edge dislocations is proposed using DE-FEM, a finite element formulation enriched with discontinuities to model dislocations independent of the mesh. Although the modelling of a stationary field with dislocations is straightforward, the dynamic solution becomes much more complicated. It requires the accurate stress retrieval of the numerical stresses close to an artificial singularity and various attempts, such as eliminating the singularity by subtracting the analytical solution or incorporating a singular core enrichment, were proven to be ineffective. Recommendations are given for future attempts, but also an alternative numerical superposition approach is explained. Its results are comparable to existing methods in terms of accuracy, but the computation time is not optimal for the current implementation.

Pioneering in the aviation is dangerous, but its rewards might be worthwhile. What if the fuselage shape is challenged to be non-circular? A better volume efficiency, easier loading and a new perception of the future aircraft are within reach, but at what costs? Carry-on luggage is expected to increase in the future. Does that result in a new fuselage shape? This report shows the design process of a 200 passenger aircraft while challenging the fuselage shape and its material. Market analysis showed a great demand for sustainable, single aisle aircraft. The current competitors are the Airbus A320neo, Boeing 737MAX-8 and the Airbus A321neo. With the use of system engineering tools, such as a functional breakdown structure, a functional flow diagram and a budget breakdown, a conceptual design was constructed: the A342 Beeblebrox. It purpose is to be able to outperform state-of-the-art aircraft and remain competitive for the next 50 years. Therefore the propulsion & performance, the electronics and the control & stability were designed to surpass the current aviation standard. To this end, off the shelf geared turbofan engines are used because it has a surpassing specific fuel consumption (SFC) and an overall good performance. The A342 is slightly more stable and controllable, because of its longer fuselage length but its overall tail size is similar to the A321neo. The A342 is an All-Electric-Aircraft to reduce subsystem and fuel weight. Its accessabillity is comparable to state-of-the-art aircraft. The maintainability is slightly worse, because of the revolutionary fuselage shape, that requires more frequent checking. The direct operating costs were calculated to be comparable with the A320neo. And because the A342 can carry more payload over longer distances, this ensures its ability to outperform other aircraft. The interior is designed such to maximise volume efficiency per passenger. This defined the inner boundaries for the fuselage cross-section, for which a lightweight structure was created. From the pressurisation requirement, it follows, both analytically and using a finite element method, that rounder shapes cope better with stresses. However, the elliptical shapes might still be an option. An elliptical shape was calculated to be roughly 1500 kg heavier than the circular of the same material. The fuselage material will consist mainly of CFRP and AFRP (Carbon/Aramid Fibre Reinforced Plastics), due to their high strength and low density. For the aerodynamics of the fuselage Computational Fluid Dynamics simulation software (CFD) was used to calculate the pressure. Subsequently, the drag was calculated analytically. It can be seen that squarish fuselages decrease the wetted area which reduces the drag. The elliptical shape has an increased L/D-ratio (Lift over Drag ratio) of 2%. The final conceptual design of the A342 Beeblebrox is a 6-abreast single aisle airliner, featuring an elliptical fuselage shape with conventional tail, better SFC and all electric systems. Each passenger has 0.107 m3 overhead luggage storage and 0.05 m3 checked-in luggage. Finally, it can be concluded that the elliptical shape is feasible to compete with state-of-the-art aircraft.