Publica
Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Parameterization of Environmental Influences by Automated Characteristic Diagrams for the Decoupled Fluid and Structuralmechanical Simulations
 Journal of Machine Engineering 19 (2019), No.1, pp.98113 ISSN: 18957595 ISSN: 16426568 
 Conference on Supervising and Diagnostics of Machining Systems <30, 2019, Karpacz> 

 English 
 Journal Article, Conference Paper 
 Fraunhofer IWU () 
 machine tool; thermal error; error 
Abstract
Thermoelastic effects contribute the most to positioning errors in machine tools especially in operations where high precision machining is involved. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behaviour between the machine tool surface and the surrounding air (fluid). Heat transfer coefficient (HTC) values effectively represent this solidfluid heat transfer and it serves as the boundary data for thermoelastic simulations. Thereby, deformation results can be obtained. This twostep simulation procedure involving fluid and thermostructural simulations is highly complex and timeconsuming. A suitable alternative for the above process can be obtained by introducing a clustering algorithm (CA) and characteristic diagrams (CDs) in the workflow. CDs are continuous maps of a set of input variables onto a single output variable, which are trained using data from a limited number of CFD simulations which is optimized using the clustering technique involving genetic algorithm (GA) and radial basis function (RBF) interpolation. The parameterized environmental influences are mapped directly onto corresponding HTC values in each CD. Thus, CDs serve as lookup tables which provide boundary data (HTC values along with nodal information) under several load cases (combinations of environmental influences) for thermoelastic simulations. Ultimately, a decoupled fluidstructural simulation system is obtained where boundary (convection) data for thermomechanical simulations can be directly obtained from CDs and would no longer require fluid simulations to be carried out again. Thus, a novel approach for the correction of thermoelastic deformations on a machine tool is obtained.