To calculate the load capacity of gear stages within complex drivetrains under varying external loads, multi-body-systems (MBS) are used to simulate the vibrational behaviour of integral systems. In order to model a flexible hypoid gear stage, methods like the modal reduction of FEM-models were already introduced. However, the modelling of such systems is complex, challenging and sensitive to its discretisation. The co-simulation within a multi-body-system simulation offers the possibility to outsource the calculation of the tooth contact and therefore the reaction forces under consideration of friction. This leads to a simplification and an improvement of the modelling of gear stages in multi-body-systems.The further developed co-simulation module offers a compromise between computational speeds and exact solutions. To improve the quality of the results and reduce the calculation time the load distribution calculation is investigated specifically. The article describes a method to reduce fluctuations of computed reaction forces and moments during gear movement. The aim is to keep the level of fluctuations of a high contact zone discretisation with a significant smaller contact point count.

The classic flank and root load capacity calculation on the component surface forms the basis for the design of power gears today. However, flank fractures also occur in practice, particularly with large-module gears and/or low case-hardening depths. It is a fatigue damage with crack initiation in the tooth interior, its prevention requires the calculation of the stresses below the surface. In addition to understanding the load stresses, the inhomogeneous load bearing capacity and the residual stress profile in case-hardened gears are also of great importance. There are various calculation approaches for this in the area of cylindrical gears, but these have not yet been transferred to the complex geometry of spiral bevel gears. The focus of this publication is on estimating the residual stresses in the tooth volume by generating a three-dimensional residual stress tensor field in the bevel gear tooth based on the two-dimensional calculation approaches used to date on cylindrical gears. In combination with the stress tensor-time curves from a tooth contact simulation with the LTCA tool BECAL, this can be fed into different failure hypotheses, which is illustrated using an example.

Organic-inorganic halide perovskite solar cells have recently emerged as high performance photovoltaic devices with low cost, promising for affordable large-scale energy production. The power conversion efficiency (PCE) from solar energy to electricity in solid state photovoltaic devices has risen from 10% to over 20% within two years of development. To date, a relatively expensive organic hole-conducting molecule with low conductivity, namely Spiro-OMeTAD (2,2',7,7'-tetrakis (N,N-di-p-methoxyphenyl-amine) 9,9'- Spirobifluorene), is employed widely to achieve highly efficient perovskite solar cells. Here, we report two low cost candidates to replace spiro-OMeTAD for perovskite solar cells, Poly(3,4-ethylenedioxythiophene) (PEDOT) and copper thiocyanate (CuSCN). Stabilized power conversion efficiency of 6.6% and 9.1% can be obtained when the new materials are used as the hole-conductor respectively, comparing to 9.6% for device using Spiro-OMeTAD.