989 research outputs found
A MATLAB Code for Handling Efficiently Discontinuous BVPs
No full textThis paper focuses on the HOFiD_bvp code, initially developed by Amodio and Settanni in MATLAB for solving second-order scalar boundary value problems in ordinary differential equations. The objective of this study is to present an enhanced version of the code that can tackle problems involving one or more unknown parameters by incorporating an equivalent number of equations. Furthermore, the upgraded code demonstrates improved capability in efficiently handling discontinuous source terms and solutions. Several numerical experiments are conducted to showcase these novel features
Implementation of the PaperRank and AuthorRank indices in the Scopus database
No full textWe implement the PaperRank and AuthorRank indices introduced in [Amodio & Brugnano, 2014] in the Scopus database, in order to highlight quantitative and qualitative information that the bare number of citations and/or the h-index of an author are unable to provide. In addition to this, the new indices can be cheaply updated in Scopus, since this has a cost comparable to that of updating the number of citations. Some examples are reported to provide insight in their potentialities, as well as possible extensions
Finite Strain Analysis by Image Processing: Smoothing Techniques
No full textThe digital image processing technique can be successfully used to quickly measure surface deformations with good accuracy. In a previous paper the authors [1] described a method to measure large strain fields, which is based on digital images processing. A dot grid, previously marked on the surface of the workpiece, is acquired by two CCD cameras from two different view-points. The data are then processed by a stereoscopic procedure, which returns the dot locations in a three-dimensional space.
A similar method was developed by Zheng Tan, Merlin and Magnusson [2] in 1992. They evaluated the spatial location of many points, placed in a square grid on the surface of the specimen, by a photogrammetry derived technique. The co-ordinates of the identified are then processed using a method proposed by Sowerby et alii [3, 4], which calculates the principal strain values and directions within triangular elements, whose strain fields is assumed to be constant
Recent advances in experimental and theoretical analyis of stress and strain
No full textGuest Editor, numero speciale di Meccanic
Constitutive material law improvements for metals that manifest an unstable behavior in dynamic condition
No full textNumerical analysis is regularly used in engineering practice as useful mean to study component behavior in service, especially when an experimental campaign is too expensive or not practicable. Numerical software is becoming more and more powerful and integrated, leaving the correct use of a material model as a weak point. As some materials could manifest an unstable behavior if deformed at high strain rate, it is of primary importance to use an appropriate constitutive law to reproduce their behaviour. This paper shows the results of the inverse calibration of two material (Ti-4Al-6V and AA 7075-T6) constitutive laws in their classical definition, as present in the literature. Moreover, both of them have been modified by the authors in the attempt of improving the complex material behaviour. The calibrated models are Johnson-Cook (JC) and Nowak-Pecherski (NP) models. The improvement of these models showed that JC is not suitable for calibrate materials that show an unstable behavior also after its improvement; conversely NP provided a better matching with the experimental data
A Parallel direct method for solving initial value problems for ordinary differential equations
No full textAddendum: Considerations about the incompleteness of the Ehrenfest's theorem in quantum mechanics (2021 Eur. J. Phys. 42 065405)
No full textWe describe the analytical solution of the eigenvalue problem introduced in our article mentioned in the title and relative to a punctiform electric charge confined in an one-dimensional box in the presence of an electric field. We also derive and discuss the analytical expressions of the external forces acting on the punctiform charge and associated with the boundaries of the one-dimensional box in the presence of the electric field
Behavior of fiber reinforced metal laminates at high strain rate
No full textCarbon Fiber Reinforced Aluminum Laminate (CARALL) is a good system for energy absorption through plastic deformation in aluminum and micro-cracking in the composite layers. Moreover, CARALL FMLs also provide excellent impact resistance due to the presence of aluminum layer. The focus of this research is to characterize the CARALL behavior under dynamic conditions. High strain rate tests on sheet laminate samples have been carried out by means of direct Split Hopkinson Tension Bar. The sample geometry and the clamping system were optimized by FEM simulations. The clamping system has been designed and optimized in order reduce impedance disturbance due to the fasteners and to avoid the excessive plastic strain outside the gauge region of the samples
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