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Papers by Borja Coto
International Journal of Advanced Manufacturing Technology, 2011
The study of the residual stresses of parts that work under extreme conditions is of great intere... more The study of the residual stresses of parts that work under extreme conditions is of great interest, as they will influence the mechanical behavior of the components. This has a huge importance in the automotive and aeronautics sectors, in components such as power shafts or aircraft landing gears. Machining processes produce thermal and mechanical loads causing residual stresses in the surface of the finished component. The influence of the cutting parameters on the surface residual stresses generated during turning of AISI 4340 (40NiCrMo7) treated steel was analyzed. Surface residual stresses were measured using the X-ray diffraction technique and the sin2ψ method. Both magnitude and direction of the residual stresses were assessed in order to understand how the cutting parameters affect the principal stresses directions and the homogeneity of the distribution of stresses. The ANOVA analysis has been used, obtaining the process window to reduce the tensile residual stresses affecting the component behavior against fatigue loads. When feed is increased, more heat is generated during the cutting process, leading to more tensile residual stresses. An increase in cutting speed results in a more adiabatic process (less heating of the part because heat is dissipated through the chip) that also leads to less tensile stresses. It has been observed that the maximum stress is localized around 30° from the cutting direction.
Polymer, 2010
This paper analyzes the miscibility state of Poly(L-Lactide) (PLLA) and Poly(DL-Lactide) (PDLLA) ... more This paper analyzes the miscibility state of Poly(L-Lactide) (PLLA) and Poly(DL-Lactide) (PDLLA) with Poly (styrene) (PS) and Poly(vinyl phenol) (PVPh) by means of Molecular Dynamics (MD) simulations performed using the COMPASS force-field. Immiscibility was found in polylactide/PS blends while miscibility was the result in polylactide/PVPh blends, both previsions agreeing with the experimental behaviour.
Computational Materials Science, 2011
The effect of carboxylation on axial Young's modulus of carbon nanotubes is investigated using a ... more The effect of carboxylation on axial Young's modulus of carbon nanotubes is investigated using a molecular dynamics (MD) approach. COMPASS force field is used to model the interatomic interactions in single wall (SWCNT) and multiwall carbon (MWCNT) with different amounts of -COOH groups attached to their surfaces. The results of the MD simulations show how an increase of the number of carboxylic groups on the CNT surface leads to a decrease on the Young moduli of the CNTs. The decrease of MWCNT Young's modulus is found to be lower than in the case of SWCNT.
International Journal of Advanced Manufacturing Technology, 2011
The study of the residual stresses of parts that work under extreme conditions is of great intere... more The study of the residual stresses of parts that work under extreme conditions is of great interest, as they will influence the mechanical behavior of the components. This has a huge importance in the automotive and aeronautics sectors, in components such as power shafts or aircraft landing gears. Machining processes produce thermal and mechanical loads causing residual stresses in the surface of the finished component. The influence of the cutting parameters on the surface residual stresses generated during turning of AISI 4340 (40NiCrMo7) treated steel was analyzed. Surface residual stresses were measured using the X-ray diffraction technique and the sin2ψ method. Both magnitude and direction of the residual stresses were assessed in order to understand how the cutting parameters affect the principal stresses directions and the homogeneity of the distribution of stresses. The ANOVA analysis has been used, obtaining the process window to reduce the tensile residual stresses affecting the component behavior against fatigue loads. When feed is increased, more heat is generated during the cutting process, leading to more tensile residual stresses. An increase in cutting speed results in a more adiabatic process (less heating of the part because heat is dissipated through the chip) that also leads to less tensile stresses. It has been observed that the maximum stress is localized around 30° from the cutting direction.
Polymer, 2010
This paper analyzes the miscibility state of Poly(L-Lactide) (PLLA) and Poly(DL-Lactide) (PDLLA) ... more This paper analyzes the miscibility state of Poly(L-Lactide) (PLLA) and Poly(DL-Lactide) (PDLLA) with Poly (styrene) (PS) and Poly(vinyl phenol) (PVPh) by means of Molecular Dynamics (MD) simulations performed using the COMPASS force-field. Immiscibility was found in polylactide/PS blends while miscibility was the result in polylactide/PVPh blends, both previsions agreeing with the experimental behaviour.
Computational Materials Science, 2011
The effect of carboxylation on axial Young's modulus of carbon nanotubes is investigated using a ... more The effect of carboxylation on axial Young's modulus of carbon nanotubes is investigated using a molecular dynamics (MD) approach. COMPASS force field is used to model the interatomic interactions in single wall (SWCNT) and multiwall carbon (MWCNT) with different amounts of -COOH groups attached to their surfaces. The results of the MD simulations show how an increase of the number of carboxylic groups on the CNT surface leads to a decrease on the Young moduli of the CNTs. The decrease of MWCNT Young's modulus is found to be lower than in the case of SWCNT.