An extended shear angle model derived from in situ strain measurements during orthogonal cutting

Spatial Internal Material Load and Residual Stress Distribution Evolution in Synchrotron In Situ Investigations of Deep Rolling

“…With this, several strain components can be assumed zero, i.e., ε xx = 0, ε xz = 0, and ε xy = 0. The approach is comparable to the orthogonal cutting setup and the strain state confirmed through FEM-simulation by Uhlmann et al [5] for a similar transmission geometry. Thus, for further analysis the fundamental equation was reduced to Equation (1):…”

“…The different methods are well indicated for in situ analysis of the material state, for example, through the width of a processed sample in transmission geometry without interfering with the analyzed material itself, as it is the case when sensors are embedded into the target material as done by Dumstorff and Lang [4]. In situ X-ray diffraction investigations during a manufacturing process have already been performed by Uhlmann et al [5] using synchrotron radiation along multiple measurement positions for an orthogonal cutting process. These experiments were performed in transmission geometry and followed the local strain and stress development around the contact zone of the cutting tool, as well as the evolution of texture in the machined sample.…”

In Situ X-ray Diffraction Analysis of Stresses during Deep Rolling of Steel

“…These types of measurements provide information about the spatial and temporal evolution of the material state using synchrotron X-ray diffraction analysis. In situ measurement during processes was also established to investigate internal material load during the orthogonal cutting process by Uhlmann et al [4], or to analyze the change in microstructure during welding by Staron et al [5]. For mechanical processing effects, the deep rolling process gives a very specific set of contact parameters leading to the plastification of the surface and inducing material modifications several millimeters inside of the specimen, which was measured for static indentation in a previously published study by Meyer et al [6], where it was shown that the loading and residual stress fields are symmetric without sample movement.…”

In-Situ Analysis of Material Modifications During Deep Rolling by Synchrotron X-Ray Diffraction Experiments

“…Using the α{211} reflex of the material state, strain value was calculated from the diffraction rings for each of the 960 points in the measurement window, using the fundamental equation of strain as given by Noyan and Cohen [7]. It was determined that only the ε yy , ε zz and ε yz strain components in the respective coordinate system have to be analyzed (Eq.1) in a plane strain approach, since the boundary conditions of the specimen only introduce negligible deviations in this mode, as found by Uhlmann et al [5] for a comparable orthogonal cutting process. ε θδ (y,z)= cos 2 θ sin 2 ϕ ε yy (y,z)+ cos 2 θ cos 2 ϕ ε zz (y,z)+ cosθ sin 2ϕ ε yz (y,z)…”

“…The information about loading stresses and the resulting residual stresses from mechanical elasto-plastic deformation can give insight into the material behavior and the modification mechanisms. To actually analyze the stress fields in-situ during processing, diffraction measurements using synchrotron radiation with sufficient penetration depth are an efficient method, as shown by Uhlmann et al [5] for the analysis of an orthogonal cutting process.…”