Pär Johannesson

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In this report we will present a simple way to model and simulate random fatigue loads, which are oftenly both non-stationary and non-Gaussian. The method is based on approximating the non-Gaussian process by a transformation of a Gaussian process. The procedure can be used to simulate loads as well as calculating important cycle properties of the load such(More)
We will present an application of the probabilistic branch of Variation Mode and Effect Analysis (VMEA) implemented as a first order, second moment reliability method. First order means that the failure function is approximated to be linear with respect to the main influencing variables, while second moment means that only means and variances are taken into(More)
Hand hygiene, cleaning and disinfection are pre-requirements for hygiene management in hospital settings and the food industry. In order to facilitate risk management, different contamination scenarios and interventions need to be evaluated. In the present study data on transfer rates and reductions of Staphylococcus aureus were provided in an experimental(More)
iii Foreword This is a tutorial for how to use the MATLAB toolbox WAFO for analysis and simulation of random waves and random fatigue. The toolbox consists of a number of MATLAB m-files together with executable routines from FORTRAN or C++ source, and it requires only a standard MATLAB setup, with no additional toolboxes. A main and unique feature of WAFO(More)
How does the fatigue damage to a vehicle depend on the usage of the vehicle? When it is used in its natural environment by a customer, both the drivers and the environmental properties vary in a more or less random way. One can say that the vehicle is subjected to a series of diierent load cases, each with its typical behaviour. Here, the series of diierent(More)
A switching random load, which is a sequential mixture of different random subloads, is modelled by using a hidden Markov model. The basic assumptions are that the turning points of each subload is modelled by a Markov chain, and that the switching between the subloads follow a Markov chain. An algorithm for computing the rainflow matrix for such a load is(More)
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