publications

2026

1. Improved residual stress evaluation with Hole-Drilling and DIC through the L-curve tool and super-resolution along depth

   Tommaso Grossi, Paolo Neri , and Ciro Santus

   Measurement, Jan 2026

   Abs

   Full-field methods such as Electronic Speckle Pattern Interferometry (ESPI) and Digital Image Correlation (DIC) emerge as promising alternatives to strain rosette in the hole-drilling method, each with its own advantages and limitations. In particular, DIC stands out as a method requiring minimal (and cheap) specimen preparation; however, its sensitivity is approximately one order of magnitude lower than that of conventional strain gauge techniques. We address two fundamental questions. First, how can the inverse problem of the hole-drilling method be systematically approached outside the well-established framework of ASTM E837, which provides users with comprehensive guidance, including automated regularization procedures? Second, thanks to full-field measurement techniques, is it possible to retrieve stress distributions at a spatial resolution finer than the drilling step? We revisit the theoretical development of the inverse problem, aiming to directly identify the residual stresses from raw images, without intermediate pre-processing of the displacement fields. We introduce the L-curve method – well established in other scientific domains – as a rational tool for the choice of the regularization parameter. Finally, we show that, in principle, it would be possible to identify the entire stress distribution from a single drilling increment. We perform a deep rolling treatment on an aluminum specimen and compare the residual stresses identified using both a strain gauge rosette and DIC. We demonstrate that the proposed framework yields results comparable to those obtained using strain gauge rosettes, while minimizing user-dependent arbitrariness. Furthermore, we show that depth super-resolution of at least a factor of two is already achievable with current technological capabilities.

2. Improving sustainability of cold rolling of low-carbon steels via oil free lubricants

   Valentina Colla , Orlando Toscanelli , Tommaso Grossi, and 15 more authors

   Matériaux & Techniques, Jan 2026

   Abs

   The European steel sector is committed to improve sustainability of the whole steel production chain, from decarbonisation of major upstream processes up to all downstream operations, including rolling. In particular, in the cold rolling process, oil-in-water emulsions are usually applied to lubricate the cold rolling process of low-Carbon steel. Such emulsions present some drawbacks mainly related to emulsion bath maintenance, subsequent production stages and waste disposal. Past research works showed that in some application areas, Oil Free Lubricants (OFL) show lubricant properties that are comparable to conventional lubricants, while providing significant environmental benefits. These lubricants are formulated as aqueous dispersions of Polyalkylene Glycols (PAG), a water-soluble synthetic polymer base, combined with various additives for lubrication enhancement, corrosion protection, and oil rejection. The project entitled “Transfer of aqueous oil free lubricants into steel cold rolling practice” (Ref. RollOilFree II – G.A. No 101112433) aims at developing an Oil-Free Lubricant for the cold rolling process of low-Carbon steel for applications in the automotive and packaging sectors by assessing its performance in industrial conditions. To this aim, the project combines tests at laboratory scale and simulations with trials in an industrial pilot cold rolling mill and, finally, field trials at industrial scale. Results demonstrate that OFL01 and OFL02 represent the most promising formulations as substitutes for commercial lubricants. The paper overviews the work undertaken in the first 18 months of the project, including laboratory investigations and part of the pilot trials.

2025

1. NeuberNet: a neural operator solving elastic-plastic partial differential equations at V-notches from low-fidelity elastic simulations

   Tommaso Grossi, Marco Beghini , and Matteo Benedetti

   Nature Communications Engineering, Dec 2025

   Abs

   Abstract We present NeuberNet, a nonlinear manifold decoder that learns a family of operator mappings on the domain of reentrant corners between far-field displacement boundary conditions obtained with low-fidelity elastic simulations and the high-resolution stress and strain fields that stem from the elastic-plastic axisymmetric solid mechanics equations, under the only assumptions of small-scale plasticity and bilinear isotropic hardening. We envision NeuberNet as a data-driven application of the substructuring principle in solid mechanics, engineered to simulate complex geometries by employing plastic material behavior only in the vicinity of stress raisers where nonlinearities are most likely to occur. We provide practical guidelines for mesh resolution in the initial low-fidelity elastic simulations; we show how NeuberNet can detect violations of the small-scale plasticity assumption, signaling the need for full-scale nonlinear models when required; finally, we show that NeuberNet can perform zero-shot inference on 3D problems with axisymmetric geometries and non-symmetric boundary conditions.

2. Constitutive Modeling of Creep–Fatigue Interaction in 1Cr-1Mo-0.25V Steel for Hold-Time Testing

   Federico Bucciarelli , Alessandro Guazzini , Tommaso Grossi, and 2 more authors

   Metals, Sep 2025

   Abs

   In the field of energy production, creep–fatigue interaction is a typical failure mode that might compromise the structural integrity of both rotating equipment and pressure vessels. Common design practices approach the problem in a conservative way by using high safety factors, which typically results in additional costs for manufacturing companies. The aim of this article, in the framework of continuum damage mechanics approaches, is to present a novel fatigue damage-based constitutive law. The presented law is directly inspired by well-assessed creep-based rules, suggesting a similarity in the behavior. On the other hand, creep deformation and damage are calculated with a more recent approach. The identification of the model parameters was carried out by interpreting experimental results obtained from low-cycle fatigue and creep relaxation tests performed on a commonly used ferritic–martensitic steel for power generation rotor forgings. To validate the proposed models, they were used to estimate material life consumption when the material was subjected to fully reversed axial loading conditions with hold time under tensile load. Different loading conditions at different total strain ranges and hold times were simulated, and good agreement was found between the predicted and experimental life, thus confirming the validity of the proposed models.

3. NeuberNet: a neural operator solving elastic-plastic PDEs at V-notches from low-fidelity elastic simulations

   Tommaso Grossi, Marco Beghini , and Matteo Benedetti

   Research Square Preprint, Mar 2025
4. Cyclic-elastic behavior in plastically pre-strained lattice structures

   Ivan Senegaglia , Giuseppe Macoretta , Tommaso Grossi, and 1 more author

   Procedia Structural Integrity, Mar 2025

2024

1. Numerical Analysis of a Nozzle Guided Vane Filled With Lattice Structures

   I. Senegaglia , T. Grossi , G. Macoretta , and 5 more authors

   In ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition , Aug 2024

   Abs

   Abstract. Gas turbines play a critical role in industries such as power generation and aviation. Additive manufacturing has emerged as a game-changing technology for gas turbine components, offering superior design flexibility and performance enhancements...

2. Measuring Residual Stresses with Crack Compliance Methods: An Ill-Posed Inverse Problem with a Closed-Form Kernel

   M. Beghini , and T. Grossi

   Applied Mechanics, Jul 2024

   Abs

   By means of relaxation methods, residual stresses can be obtained by introducing a progressive cut or a hole in a specimen...

3. Determination of Chaboche and Bouc-Wen parameters for quenched and tempered steel

   C. Santus , L. Romanelli , T. Grossi , and 1 more author

   Journal of Theoretical and Applied Mechanics, Jul 2024

   Abs

   During cyclic loadings, metal alloys can undergo cyclic plasticity, for example, at notches...

4. Regularization of Hole-Drilling Residual Stress Measurements with Eccentric Holes: An Approach with Influence Functions

   M. Beghini , L. Bertini , M. Cococcioni , and 3 more authors

   Journal of Materials Engineering and Performance, Apr 2024

   Abs

   The hole-drilling method is one of the most widespread techniques to measure residual stresses...

5. Towards a Reliable Uncertainty Quantification in Residual Stress Measurements with Relaxation Methods: Finding Average Residual Stresses is a Well-Posed Problem

   M. Beghini , and T. Grossi

   Experimental Mechanics, Apr 2024

   Abs PDF

   Background In a previous work, the problem of identifying residual stresses through relaxation methods was demonstrated to be mathematically ill-posed...

2023

1. Tuning Modal Behavior Of Additively Manufactured Lattice Structures

   M. Beghini , T. Grossi , G. Macoretta , and 5 more authors

   Journal of Engineering for Gas Turbines and Power, Dec 2023

   Abs

   Abstract Thanks to the increasingly widespread additive manufacturing technology and promising properties, the use of Lattice Structures (LS) is becoming increasingly frequent...

2. Revealing systematic errors in hole drilling measurements through a calibration bench: the case of zero-depth data

   M. Beghini , T. Grossi , C. Santus , and 1 more author

   Journal of Theoretical, Computational and Applied Mechanics, Oct 2023

   Abs

   An accurate estimation of the measurement error in the hole drilling method is needed to choose an appropriate level of regularization and to perform a sensitivity analysis on the stress results...

3. Elastic–plastic analysis of high load ratio fatigue tests on a shot-peened quenched and tempered steel, combining the Chaboche model and the Theory of Critical Distances

   C. Santus , L. Romanelli , T. Grossi , and 4 more authors

   International Journal of Fatigue, Sep 2023

   Abs

   This study aimed to predict the uniaxial fatigue strength of shot peened notched specimens made of 42CrMo4 quenched and tempered steel...

4. Validation of a strain gauge rosette setup on a cantilever specimen: Application to a calibration bench for residual stresses

   M. Beghini , T. Grossi , and C. Santus

   Materials Today: Proceedings, Jun 2023

   Abs

   It is commonly known that the most difficult part of measuring residual stresses through diffraction or relaxation methods is the high sensitivity of the results to input errors...

5. Ill-Posedness and the Bias-Variance Tradeoff in Residual Stress Measurement Inverse Solutions

   M. Beghini , T. Grossi , M.B. Prime , and 1 more author

   Experimental Mechanics, Mar 2023

   Abs PDF

   Background Relaxation methods determine residual stresses by measuring the deformations produced by incremental removal of a subdomain of the specimen...

6. Residual stress measurements on a deep rolled aluminum specimen through X-Ray Diffraction and Hole-Drilling, validated on a calibration bench

   M. Beghini , T. Grossi , C. Santus , and 2 more authors

   IOP Conference Series: Materials Science and Engineering, Feb 2023

   Abs

   Residual stress measurements are notably affected by a high sensitivity to errors in input data...

7. Investigation of Chaboche and Bouc–Wen Parameters of Quenched and Tempered Steel and Comparison of Model Predictive Capabilities

   C. Santus , L. Romanelli , T. Grossi , and 5 more authors

   Applied Sciences, Feb 2023

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   The aim of this paper is to model the elastic–plastic uniaxial behaviour of a quenched and tempered steel...

8. A computationally fast and accurate procedure for the identification of the Chaboche isotropic-kinematic hardening model parameters based on strain-controlled cycles and asymptotic ratcheting rate

   C. Santus , T. Grossi , L. Romanelli , and 2 more authors

   International Journal of Plasticity, Jan 2023

   Abs

   The Chaboche isotropic-kinematic hardening (CIKH) model provides a versatile and realistic description of the material stress–strain behavior under generic multiaxial cyclic loadings...

2022

1. Torsional-loaded notched specimen fatigue strength prediction based on mode I and mode III critical distances and fracture surface investigations with a 3D optical profilometer

   C. Santus , L. Romanelli , T. Grossi , and 5 more authors

   International Journal of Fatigue, Aug 2022

   Abs

   Torsional and axial fatigue tests were performed on steel 42CrMo4+QT and aluminium alloy 7075-T6...

2. A calibration bench to validate systematic error compensation strategies in hole drilling measurements

   Marco Beghini , Tommaso Grossi, Ciro Santus , and 1 more author

   Jul 2022

   Abs

   An accurate estimation of the measurement error in the hole drilling method is needed to choose an appropriate level of regularization and to perform a sensitivity analysis on the stress results...

3. X-Ray Diffraction and Hole-Drilling residual stress measurements of shot peening treatments validated on a calibration bench

   M. Beghini , T. Grossi , C. Santus , and 3 more authors

   In ICSP14–14th International Conference on Shot Peening , Jul 2022

   Abs

   The inverse problem of determining residual stresses from diffraction or relaxation methods is notoriously affected by a high sensitivity to errors in input data...

4. Procedura di determinazione dei parametri di chaboche di un acciaio con comportamento elasto-plastico in regime di fatica ad alto numero di cicli

   C. Santus , L. Romanelli , T. Grossi , and 3 more authors

   In Atti della conferenza AIAS2022 , Jul 2022

   Abs

   High-strength metal alloys usually have a purely elastic behaviour during high-cycle fatigue regime...