https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sun, 07 Jun 2026 14:41:13 GMT 2026-06-07T14:41:13Z http://hdl.handle.net/10985/19440 Surface drag analysis after Ti-6Al-4V orthogonal cutting using grid distortion SELA, Andres; ORTIZ-DE-ZARATE, Gorka; SOLER, Daniel; ARISTIMUÑO, Patxi; SORIANO, Denis; GERMAIN, Guénaël; DUCOBU, François; ARRAZOLA, Pedro José Surface integrity directly affects the mechanical behavior of the workpiece, which is especially relevant on fatigue behavior. To characterize the quality of the machined surface, aspects such as material damage, roughness or residual stress are considered. Measurement of the material damage of the surface is characterized in some cases as surface drag, depth of the affected machining zone, a phenomenon which takes place due to plastic strain in the surface layer caused by machining stress which could have an influence on residual stress. Surface drag measurement done with optical microscopes has relevant uncertainty. In this paper, a methodology to measure the surface drag with lower uncertainty is proposed. The method consists of measuring the deformation of a grid as a result of the machining process. The grid was created with micromilling. The method was applied to analyze the effect of feed on the surface integrity after orthogonal cutting of Ti-6Al-4V. The depth of the affected layer was measured using a 3D optical measuring device (Alicona Infinite Focus IFG4) and compared with numerical simulations and a good agreement was achieved. In comparison with optical microscope results, it can be concluded that traditional method underestimates surface drag Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19440 2020-01-01T00:00:00Z SELA, Andres ORTIZ-DE-ZARATE, Gorka SOLER, Daniel ARISTIMUÑO, Patxi SORIANO, Denis GERMAIN, Guénaël DUCOBU, François ARRAZOLA, Pedro José Surface integrity directly affects the mechanical behavior of the workpiece, which is especially relevant on fatigue behavior. To characterize the quality of the machined surface, aspects such as material damage, roughness or residual stress are considered. Measurement of the material damage of the surface is characterized in some cases as surface drag, depth of the affected machining zone, a phenomenon which takes place due to plastic strain in the surface layer caused by machining stress which could have an influence on residual stress. Surface drag measurement done with optical microscopes has relevant uncertainty. In this paper, a methodology to measure the surface drag with lower uncertainty is proposed. The method consists of measuring the deformation of a grid as a result of the machining process. The grid was created with micromilling. The method was applied to analyze the effect of feed on the surface integrity after orthogonal cutting of Ti-6Al-4V. The depth of the affected layer was measured using a 3D optical measuring device (Alicona Infinite Focus IFG4) and compared with numerical simulations and a good agreement was achieved. In comparison with optical microscope results, it can be concluded that traditional method underestimates surface drag http://hdl.handle.net/10985/20855 Inverse Identification of the Ductile Failure Law for Ti6Al4V Based on Orthogonal Cutting Experimental Outcomes SELA, Andres; SOLER, Daniel; ORTIZ-DE-ZARATE, Gorka; GERMAIN, Guénaël; DUCOBU, François; ARRAZOLA, Pedro José Despite the prevalence of machining, tools and cutting conditions are often chosen based on empirical databases, which are hard to be made, and they are only valid in the range of conditions tested to develop it. Predictive numerical models have thus emerged as a promising approach. To function correctly, they require accurate data related to appropriate material properties (e.g., constitutive models, ductile failure law). Nevertheless, material characterization is usually carried out through thermomechanical tests, under conditions far different from those encountered in machining. In addition, segmented chips observed when cutting titanium alloys make it a challenge to develop an accurate model. At low cutting speeds, chip segmentation is assumed to be due to lack of ductility of the material. In this work, orthogonal cutting tests of Ti6Al4V alloy were carried out, varying the uncut chip thickness from 0.2 to 0.4 mm and the cutting speed from 2.5 to 7.5 m/min. The temperature in the shear zone was measured through infrared measurements with high resolution. It was observed experimentally, and in the FEM, that chip segmentation causes oscillations in the workpiece temperature, chip thickness and cutting forces. Moreover, workpiece temperature and cutting force signals were observed to be in counterphase, which was predicted by the ductile failure model. Oscillation frequency was employed in order to improve the ductile failure law by using inverse simulation, reducing the prediction error of segmentation frequency from more than 100% to an average error lower than 10%. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/20855 2021-01-01T00:00:00Z SELA, Andres SOLER, Daniel ORTIZ-DE-ZARATE, Gorka GERMAIN, Guénaël DUCOBU, François ARRAZOLA, Pedro José Despite the prevalence of machining, tools and cutting conditions are often chosen based on empirical databases, which are hard to be made, and they are only valid in the range of conditions tested to develop it. Predictive numerical models have thus emerged as a promising approach. To function correctly, they require accurate data related to appropriate material properties (e.g., constitutive models, ductile failure law). Nevertheless, material characterization is usually carried out through thermomechanical tests, under conditions far different from those encountered in machining. In addition, segmented chips observed when cutting titanium alloys make it a challenge to develop an accurate model. At low cutting speeds, chip segmentation is assumed to be due to lack of ductility of the material. In this work, orthogonal cutting tests of Ti6Al4V alloy were carried out, varying the uncut chip thickness from 0.2 to 0.4 mm and the cutting speed from 2.5 to 7.5 m/min. The temperature in the shear zone was measured through infrared measurements with high resolution. It was observed experimentally, and in the FEM, that chip segmentation causes oscillations in the workpiece temperature, chip thickness and cutting forces. Moreover, workpiece temperature and cutting force signals were observed to be in counterphase, which was predicted by the ductile failure model. Oscillation frequency was employed in order to improve the ductile failure law by using inverse simulation, reducing the prediction error of segmentation frequency from more than 100% to an average error lower than 10%. http://hdl.handle.net/10985/20335 Measurement of plastic strain and plastic strain rate during orthogonal cutting for Ti-6Al-4V SELA, Andres; ORTIZ-DE-ZARATE, Gorka; SOLER, Daniel; GERMAIN, Guénaël; ARISTIMUÑO, Patxi; ARRAZOLA, Pedro José Finite Element Modelling used to predict machining outcomes needs to be supplied with the appropriate material thermomechanical properties which are obtained by specific testing devices and methodologies. However, these tests are usually not representative of the extreme conditions achieved in machining processes and the obtained material law may not be suitable enough. Inverse identification could address this problem by obtaining material thermomechanical properties directly from machining outcomes such as cutting forces, temperatures, strain or strain rates. Nevertheless, this technique needs to be supplied with accurate machining outcomes. However, some of them such as strain or strain rate are difficult to be properly measured. The aim of this paper is to present a methodology to measure plastic strain and strain rate during orthogonal machining under plane strain conditions. The main idea is to create a physical microgrid in a workpiece and to analyze the distortion suffered by this grid. The novelty of the method consists on its capability of measuring strain and strain rate fields in a very localized area (primary shear zone) using a single image. The methodology was applied in orthogonal cutting of Ti-6Al-4V under cutting conditions that are representative of the broaching process. Experimental results were compared with DIC measurements, analytical results based on unequal division shear zone model, literature results and with numerical fields obtained from an AdvantEdge-2D model. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/20335 2021-01-01T00:00:00Z SELA, Andres ORTIZ-DE-ZARATE, Gorka SOLER, Daniel GERMAIN, Guénaël ARISTIMUÑO, Patxi ARRAZOLA, Pedro José Finite Element Modelling used to predict machining outcomes needs to be supplied with the appropriate material thermomechanical properties which are obtained by specific testing devices and methodologies. However, these tests are usually not representative of the extreme conditions achieved in machining processes and the obtained material law may not be suitable enough. Inverse identification could address this problem by obtaining material thermomechanical properties directly from machining outcomes such as cutting forces, temperatures, strain or strain rates. Nevertheless, this technique needs to be supplied with accurate machining outcomes. However, some of them such as strain or strain rate are difficult to be properly measured. The aim of this paper is to present a methodology to measure plastic strain and strain rate during orthogonal machining under plane strain conditions. The main idea is to create a physical microgrid in a workpiece and to analyze the distortion suffered by this grid. The novelty of the method consists on its capability of measuring strain and strain rate fields in a very localized area (primary shear zone) using a single image. The methodology was applied in orthogonal cutting of Ti-6Al-4V under cutting conditions that are representative of the broaching process. Experimental results were compared with DIC measurements, analytical results based on unequal division shear zone model, literature results and with numerical fields obtained from an AdvantEdge-2D model.