elisabetta zanetti | University of Perugia (original) (raw)

Papers by elisabetta zanetti

Research paper thumbnail of Bladder tissue biomechanical behavior: Experimental tests and constitutive formulation

Journal of Biomechanics, Sep 1, 2015

A procedure for the constitutive analysis of bladder tissues mechanical behavior is provided, by ... more A procedure for the constitutive analysis of bladder tissues mechanical behavior is provided, by using a coupled experimental and computational approach. The first step pertains to the design and development of mechanical tests on specimens from porcine bladders. The bladders have been harvested, and the specimens have been subjected to uniaxial cyclic tests at different strain rates along preferential directions, considering the distribution of tissue fibrous components. Experimental results showed the anisotropic, non-linear and time-dependent stress-strain behavior, due to tissue conformation with fibers distributed along preferential directions and their interaction phenomena with ground substance. In detail, experimental data showed a greater tissue stiffness along transversal direction. Viscous behavior was assessed by strain rate dependence of stress-strain curves and hysteretic phenomena. The second step pertains the development of a specific fiber-reinforced visco-hyperelastic constitutive model, in the light of bladder tissues structural conformation and experimental results. Constitutive parameters have been identified by minimizing the discrepancy between model and experimental data. The agreement between experimental and model results represent a term for evaluating the reliability of the constitutive models by means of the proposed operational procedure.

Research paper thumbnail of Driver-Handlebar Injury in Scooter-Car Collision

Journal of Biomechanics, Jul 1, 2012

In bicycle and scooter accidents, direct impact with the handlebar can cause serious abdominal in... more In bicycle and scooter accidents, direct impact with the handlebar can cause serious abdominal injuries, even in low-speed crashes (Nadler et al, 2005). Most abdominal injuries occur in automobile accidents (Stalnaker, 1985); therefore injury criteria have been developed with reference to car accident with frontal or lateral impact. In frontal impact; driver-steering wheel collision can be readily assimilated to scooter-driver handlebar collision. A thorough review of the abdominal injury criteria has been recently introduced inside a European project APROSYS (Advanced Protective Systems), focused on scientific and technology development in the field of passive safety. According to this review, peak force injury criteria is one of the most suitable criteria for the analysis of driver-handlebar collision.

Research paper thumbnail of Progetto e costruzione di un sistema di carico per il bacino umano

Research paper thumbnail of Metodi numerici e sperimentali per la valutazione pre-clinica di ricostruzioni complesse

Research paper thumbnail of Stress pattern in a prosthetic stem: FE comparison between the standardised experimental fatigue test (ISO 7206) and actual stresses on an implanted stem

Research paper thumbnail of Frontal Vehicle-End Optimization in Relation to Pedestrian-Car Impact

Journal of Biomechanics, Jul 1, 2012

Research paper thumbnail of Multiscale Mechanical Characterization of Polyether-2-ketone (PEKK) for Biomedical Application

Bioengineering, Feb 29, 2024

Research paper thumbnail of Ex vivo biomechanical evaluation of polyester and polyblend suture techniques to perform equine laryngoplasty

Veterinary Surgery, Feb 7, 2022

ObjectiveTo validate the use of a polyblend tape suture in equine laryngoplasty (PL).Study design... more ObjectiveTo validate the use of a polyblend tape suture in equine laryngoplasty (PL).Study designExperimental study.AnimalsThirty‐two cadaveric larynges.MethodsEach larynx was randomly assigned to 1 of 4 groups: PL with polyblend tape suture (TigerTape), without (TT) or with a cannula (TTC) in the muscular process of the arytenoid cartilage, and PL with polyester suture (Ethibond), without (EB) or with a cannula (EBC). Construct stiffness, total migration, creep, and drift values were measured after 3000 cycles. The specimens were then loaded to failure to assess their residual properties: load at failure, total energy, displacement, and 2 stiffness coefficients.ResultsAfter cyclic testing, the total migration and creep were lower in TTC (6.36 ± 1.20 mm; 1.35 ± 0.38 mm/s) than in EB (11.12 ± 4.20 mm; 3.39 ± 2.68 mm/s) and in the TT constructs (11.26 ± 1.49 mm; 3.20 ± 0.54 mm/s); however, no difference was found with EBC (9.19 ± 3.18 mm; 2.14 ± 0.99). A correlation was found between total migration and creep (R = .85). The TTC constructs failed at higher loads (129.51 ± 33.84 N) than EB (93.16 ± 18.21 N) and EBC (81.72 ± 13.26 N) whereas the EB and EBC constructs were less stiff than TT and TTC (P < .001).ConclusionBiomechanical properties were generally superior for the TTC constructs tested under cyclical loading. The TT and TTC constructs failed at a higher load than EB and EBC constructs. The cannula in TTC and EBC reduced the failure at the muscular process.Clinical significanceThese results provide evidence to support the in vivo evaluation of the polyblend tape suture with or without a cannula in the muscular process for laryngoplasty in horses.

Research paper thumbnail of Stochastic PCA-Based Bone Models from Inverse Transform Sampling: Proof of Concept for Mandibles and Proximal Femurs

Applied sciences, Jun 3, 2021

Research paper thumbnail of From an ellipsoid-based to an anthropomorphic articulated total body model for multibody applications

International Journal On Interactive Design And Manufacturing (ijidem), Jul 25, 2023

Research paper thumbnail of Design of a Snap-Fit Joint Through a Multibody Model

Springer eBooks, Sep 25, 2022

Research paper thumbnail of A Benchmark of Traditional Visual Descriptors and Convolutional Networks ‘Off-the-Shelf’ for Anomaly Detection

Springer eBooks, Sep 25, 2022

Research paper thumbnail of Compensation of the non-uniformity of back-lighting sources when digitising X-ray films for video-densitometric measures

Journal of Biomedical Graphics and Computing, Sep 17, 2012

Research paper thumbnail of Bladder tissue passive response to monotonic and cyclic loading

Biorheology, 2012

The fundamental passive mechanical properties of the bladder need to be known in order to design ... more The fundamental passive mechanical properties of the bladder need to be known in order to design the most appropriate long-term surgical repair procedures and develop materials for bladder reconstruction. This study has focused on the bladder tissue viscoelastic behavior, providing a comprehensive analysis of the effects of fibers orientation, strain rate and loading history. Whole bladders harvested from one year old fat pigs (160 kg approximate weight) were dissected along the apex-to-base direction and samples were isolated from the lateral region of the wall, as well as along apex-to-base and transverse directions. Uniaxial monotonic (stress relaxation) and cyclic tests at different frequencies have been performed with the Bose Electroforce ® 3200. Normalized stress relaxation functions have been interpolated using a second order exponential series and loading and unloading stress-strain curves have been interpolated with a non-linear elastic model. The passive mechanical behavior of bladder tissue was shown to be heavily influenced by frequency and loading history, both in monotonic and cyclic tests. The anisotropy of the tissue was evident in monotonic and in cyclic tests as well, especially in tests performed on an exercised tissue and at high frequencies. In contrast, transverse and apex-to-base samples demonstrated an analogous relaxation behavior.

Research paper thumbnail of A 3D printed conversion device for the equi-biaxial mechanical characterization of human acellular dermal matrix

Research paper thumbnail of Equi-Biaxial Tests for Mechanical Characterization of Human Acellular Dermal Matrices Through a Custom-Made Biaxial Fixture

WIT transactions on engineering sciences, Jun 21, 2017

Human Acellular Dermal Matrices (HADMs) have recently been employed in reconstructive surgeries w... more Human Acellular Dermal Matrices (HADMs) have recently been employed in reconstructive surgeries which involve high mechanical resistance prerequisites (e.g. rotator cuff tears repair, Achilles tendon augmentation, breast reconstruction procedure, hernia repair), having proved its non-immunogenic response and promising mechanical properties. Nevertheless, a thorough mechanical characterization is needed in order to test HADMs response when subjected to stress levels comparable to those experienced in vivo, to confirm its applicability to the above mentioned surgical fields and to provide precise indications to surgeons. HADMs specimens have undergone biaxial tests through a custom made biaxial fixture interfaced with a uniaxial universal testing machine. Stress-strain curves were evaluated from biaxial loads measured by two load cells, and the optical measure of the displacement of four markers located in central area of specimens. Comparisons among the native human reticular dermis and HADMs demonstrated the loss of mechanical strength caused by the decellularization process. Moreover, the specimens resulted, on average, less extensible in the medio-lateral direction (namely, along the Langer lines) than in the cranio-caudal direction, confirming the correlation of dermis mechanical response with collagen fibers orientation.

Research paper thumbnail of Femoral implants comparison by means of thermoelastic stress analysis

Journal of Biomechanics, 2006

Journal of Biomechanics, Volume 39, Issue null, Pages S515-S516, 2006, Authors:EM Zanetti; SS Mus... more Journal of Biomechanics, Volume 39, Issue null, Pages S515-S516, 2006, Authors:EM Zanetti; SS Musso; AL Audenino.

Research paper thumbnail of Radiograph processing for quantitative assessment of bone remodelling

Medical Engineering & Physics, Jul 1, 1996

Vide&ensitom&ric analysis has proved useful in the study of bone remodelling; however, for more e... more Vide&ensitom&ric analysis has proved useful in the study of bone remodelling; however, for more efJicient results, an investigation procedure that enables the comparison of X-rays is needed. In the present research an automated method has been developed which considerably speeds up the entire procedure through the implementation of specially designed C++ software. At present, a sequence of six X-rays can be analysed in about 1 h irrespective of the number of areas to be investigated, which can be arbitrarily increased (200 or more), Analysis is fast as well as more reliable and accurate. In clinical practice, the results off er an effective support to observations on the biomechanical behaviour of bone implant systems. Copyright

Research paper thumbnail of Correlation between thermography and internal damping in metals

International Journal of Fatigue, Apr 1, 2003

The object of this paper is an investigation of the relationship existing between two experimenta... more The object of this paper is an investigation of the relationship existing between two experimental techniques, both aimed at the assessment of micro-plastic phenomena and micro-friction inside a material: thermographic analysis and specific damping measurement. A model has been developed here considering the main thermal effects during fatigue tests, and a theoretical relationship between temperature increment and specific damping has been proposed. Successively, an extensive experimentation has been carried on groups ...

Research paper thumbnail of A Constitutive Framework for Human Dermis Mechanical Modelling

WIT transactions on engineering sciences, Jun 21, 2017

Finite element models, in conjunction with adequate constitutive relations of the materials invol... more Finite element models, in conjunction with adequate constitutive relations of the materials involved, have proved to be crucial in many medical applications, such as in surgical planning. Nevertheless, a thorough numerical analysis of dermis' mechanical response is a challenging research area because of dermis' highly anisotropic and nonlinear behaviour. The aim of this work has been to assess the performance of two orthotropic and one isotropic hyper-elastic constitutive laws, providing an experimental-computational framework for the definition of reliable constitutive models of dermis tissue. Experimental, equi-biaxial stress-strain data obtained on human reticular dermis specimens have been exploited in order to extract, through a stochastic optimization procedure, constitutive parameters of three widely used constitutive laws: the Ogden, Holzapfel and Gasser-Ogden-Holzapfel (GOH) models. A set of specimen specific parameters and a set of best matching parameters, determined by simultaneously fitting all experimental stress-strain curves, have been obtained. The goodness of the selected laws has been assessed by means of FEM simulations performed in Abaqus (Simulia, Dessault Systèmes Inc.) which reproduce the actual specimen boundary conditions and geometry, rebuilt through an image segmentation process implemented in MATLAB (The MathWorks, Inc.). Models have been validated comparing experimental and numerical outcomes related to reference points on the specimen surface. In the preliminary fitting phase, Normalized Root Mean Square Error values were above 0.9 for the specimen-specific and above 0.54 for the best matching models. The comparison between numerical and experimental outcomes has highlighted the inadequacy of the isotropic constitutive law in reproducing the dermis behaviour, particularly at higher stretch levels. Errors obtained in the horizontal loading direction are lower than 40% for Holzapfel and GOH models, while the Ogden model reaches the 80%. Lower and more uniform errors occur in the orthogonal direction, which settles below 30% for the orthotropic laws, while it increases up to 40% in the isotropic case.

Research paper thumbnail of Bladder tissue biomechanical behavior: Experimental tests and constitutive formulation

Journal of Biomechanics, Sep 1, 2015

A procedure for the constitutive analysis of bladder tissues mechanical behavior is provided, by ... more A procedure for the constitutive analysis of bladder tissues mechanical behavior is provided, by using a coupled experimental and computational approach. The first step pertains to the design and development of mechanical tests on specimens from porcine bladders. The bladders have been harvested, and the specimens have been subjected to uniaxial cyclic tests at different strain rates along preferential directions, considering the distribution of tissue fibrous components. Experimental results showed the anisotropic, non-linear and time-dependent stress-strain behavior, due to tissue conformation with fibers distributed along preferential directions and their interaction phenomena with ground substance. In detail, experimental data showed a greater tissue stiffness along transversal direction. Viscous behavior was assessed by strain rate dependence of stress-strain curves and hysteretic phenomena. The second step pertains the development of a specific fiber-reinforced visco-hyperelastic constitutive model, in the light of bladder tissues structural conformation and experimental results. Constitutive parameters have been identified by minimizing the discrepancy between model and experimental data. The agreement between experimental and model results represent a term for evaluating the reliability of the constitutive models by means of the proposed operational procedure.

Research paper thumbnail of Driver-Handlebar Injury in Scooter-Car Collision

Journal of Biomechanics, Jul 1, 2012

In bicycle and scooter accidents, direct impact with the handlebar can cause serious abdominal in... more In bicycle and scooter accidents, direct impact with the handlebar can cause serious abdominal injuries, even in low-speed crashes (Nadler et al, 2005). Most abdominal injuries occur in automobile accidents (Stalnaker, 1985); therefore injury criteria have been developed with reference to car accident with frontal or lateral impact. In frontal impact; driver-steering wheel collision can be readily assimilated to scooter-driver handlebar collision. A thorough review of the abdominal injury criteria has been recently introduced inside a European project APROSYS (Advanced Protective Systems), focused on scientific and technology development in the field of passive safety. According to this review, peak force injury criteria is one of the most suitable criteria for the analysis of driver-handlebar collision.

Research paper thumbnail of Progetto e costruzione di un sistema di carico per il bacino umano

Research paper thumbnail of Metodi numerici e sperimentali per la valutazione pre-clinica di ricostruzioni complesse

Research paper thumbnail of Stress pattern in a prosthetic stem: FE comparison between the standardised experimental fatigue test (ISO 7206) and actual stresses on an implanted stem

Research paper thumbnail of Frontal Vehicle-End Optimization in Relation to Pedestrian-Car Impact

Journal of Biomechanics, Jul 1, 2012

Research paper thumbnail of Multiscale Mechanical Characterization of Polyether-2-ketone (PEKK) for Biomedical Application

Bioengineering, Feb 29, 2024

Research paper thumbnail of Ex vivo biomechanical evaluation of polyester and polyblend suture techniques to perform equine laryngoplasty

Veterinary Surgery, Feb 7, 2022

ObjectiveTo validate the use of a polyblend tape suture in equine laryngoplasty (PL).Study design... more ObjectiveTo validate the use of a polyblend tape suture in equine laryngoplasty (PL).Study designExperimental study.AnimalsThirty‐two cadaveric larynges.MethodsEach larynx was randomly assigned to 1 of 4 groups: PL with polyblend tape suture (TigerTape), without (TT) or with a cannula (TTC) in the muscular process of the arytenoid cartilage, and PL with polyester suture (Ethibond), without (EB) or with a cannula (EBC). Construct stiffness, total migration, creep, and drift values were measured after 3000 cycles. The specimens were then loaded to failure to assess their residual properties: load at failure, total energy, displacement, and 2 stiffness coefficients.ResultsAfter cyclic testing, the total migration and creep were lower in TTC (6.36 ± 1.20 mm; 1.35 ± 0.38 mm/s) than in EB (11.12 ± 4.20 mm; 3.39 ± 2.68 mm/s) and in the TT constructs (11.26 ± 1.49 mm; 3.20 ± 0.54 mm/s); however, no difference was found with EBC (9.19 ± 3.18 mm; 2.14 ± 0.99). A correlation was found between total migration and creep (R = .85). The TTC constructs failed at higher loads (129.51 ± 33.84 N) than EB (93.16 ± 18.21 N) and EBC (81.72 ± 13.26 N) whereas the EB and EBC constructs were less stiff than TT and TTC (P < .001).ConclusionBiomechanical properties were generally superior for the TTC constructs tested under cyclical loading. The TT and TTC constructs failed at a higher load than EB and EBC constructs. The cannula in TTC and EBC reduced the failure at the muscular process.Clinical significanceThese results provide evidence to support the in vivo evaluation of the polyblend tape suture with or without a cannula in the muscular process for laryngoplasty in horses.

Research paper thumbnail of Stochastic PCA-Based Bone Models from Inverse Transform Sampling: Proof of Concept for Mandibles and Proximal Femurs

Applied sciences, Jun 3, 2021

Research paper thumbnail of From an ellipsoid-based to an anthropomorphic articulated total body model for multibody applications

International Journal On Interactive Design And Manufacturing (ijidem), Jul 25, 2023

Research paper thumbnail of Design of a Snap-Fit Joint Through a Multibody Model

Springer eBooks, Sep 25, 2022

Research paper thumbnail of A Benchmark of Traditional Visual Descriptors and Convolutional Networks ‘Off-the-Shelf’ for Anomaly Detection

Springer eBooks, Sep 25, 2022

Research paper thumbnail of Compensation of the non-uniformity of back-lighting sources when digitising X-ray films for video-densitometric measures

Journal of Biomedical Graphics and Computing, Sep 17, 2012

Research paper thumbnail of Bladder tissue passive response to monotonic and cyclic loading

Biorheology, 2012

The fundamental passive mechanical properties of the bladder need to be known in order to design ... more The fundamental passive mechanical properties of the bladder need to be known in order to design the most appropriate long-term surgical repair procedures and develop materials for bladder reconstruction. This study has focused on the bladder tissue viscoelastic behavior, providing a comprehensive analysis of the effects of fibers orientation, strain rate and loading history. Whole bladders harvested from one year old fat pigs (160 kg approximate weight) were dissected along the apex-to-base direction and samples were isolated from the lateral region of the wall, as well as along apex-to-base and transverse directions. Uniaxial monotonic (stress relaxation) and cyclic tests at different frequencies have been performed with the Bose Electroforce ® 3200. Normalized stress relaxation functions have been interpolated using a second order exponential series and loading and unloading stress-strain curves have been interpolated with a non-linear elastic model. The passive mechanical behavior of bladder tissue was shown to be heavily influenced by frequency and loading history, both in monotonic and cyclic tests. The anisotropy of the tissue was evident in monotonic and in cyclic tests as well, especially in tests performed on an exercised tissue and at high frequencies. In contrast, transverse and apex-to-base samples demonstrated an analogous relaxation behavior.

Research paper thumbnail of A 3D printed conversion device for the equi-biaxial mechanical characterization of human acellular dermal matrix

Research paper thumbnail of Equi-Biaxial Tests for Mechanical Characterization of Human Acellular Dermal Matrices Through a Custom-Made Biaxial Fixture

WIT transactions on engineering sciences, Jun 21, 2017

Human Acellular Dermal Matrices (HADMs) have recently been employed in reconstructive surgeries w... more Human Acellular Dermal Matrices (HADMs) have recently been employed in reconstructive surgeries which involve high mechanical resistance prerequisites (e.g. rotator cuff tears repair, Achilles tendon augmentation, breast reconstruction procedure, hernia repair), having proved its non-immunogenic response and promising mechanical properties. Nevertheless, a thorough mechanical characterization is needed in order to test HADMs response when subjected to stress levels comparable to those experienced in vivo, to confirm its applicability to the above mentioned surgical fields and to provide precise indications to surgeons. HADMs specimens have undergone biaxial tests through a custom made biaxial fixture interfaced with a uniaxial universal testing machine. Stress-strain curves were evaluated from biaxial loads measured by two load cells, and the optical measure of the displacement of four markers located in central area of specimens. Comparisons among the native human reticular dermis and HADMs demonstrated the loss of mechanical strength caused by the decellularization process. Moreover, the specimens resulted, on average, less extensible in the medio-lateral direction (namely, along the Langer lines) than in the cranio-caudal direction, confirming the correlation of dermis mechanical response with collagen fibers orientation.

Research paper thumbnail of Femoral implants comparison by means of thermoelastic stress analysis

Journal of Biomechanics, 2006

Journal of Biomechanics, Volume 39, Issue null, Pages S515-S516, 2006, Authors:EM Zanetti; SS Mus... more Journal of Biomechanics, Volume 39, Issue null, Pages S515-S516, 2006, Authors:EM Zanetti; SS Musso; AL Audenino.

Research paper thumbnail of Radiograph processing for quantitative assessment of bone remodelling

Medical Engineering & Physics, Jul 1, 1996

Vide&ensitom&ric analysis has proved useful in the study of bone remodelling; however, for more e... more Vide&ensitom&ric analysis has proved useful in the study of bone remodelling; however, for more efJicient results, an investigation procedure that enables the comparison of X-rays is needed. In the present research an automated method has been developed which considerably speeds up the entire procedure through the implementation of specially designed C++ software. At present, a sequence of six X-rays can be analysed in about 1 h irrespective of the number of areas to be investigated, which can be arbitrarily increased (200 or more), Analysis is fast as well as more reliable and accurate. In clinical practice, the results off er an effective support to observations on the biomechanical behaviour of bone implant systems. Copyright

Research paper thumbnail of Correlation between thermography and internal damping in metals

International Journal of Fatigue, Apr 1, 2003

The object of this paper is an investigation of the relationship existing between two experimenta... more The object of this paper is an investigation of the relationship existing between two experimental techniques, both aimed at the assessment of micro-plastic phenomena and micro-friction inside a material: thermographic analysis and specific damping measurement. A model has been developed here considering the main thermal effects during fatigue tests, and a theoretical relationship between temperature increment and specific damping has been proposed. Successively, an extensive experimentation has been carried on groups ...

Research paper thumbnail of A Constitutive Framework for Human Dermis Mechanical Modelling

WIT transactions on engineering sciences, Jun 21, 2017

Finite element models, in conjunction with adequate constitutive relations of the materials invol... more Finite element models, in conjunction with adequate constitutive relations of the materials involved, have proved to be crucial in many medical applications, such as in surgical planning. Nevertheless, a thorough numerical analysis of dermis' mechanical response is a challenging research area because of dermis' highly anisotropic and nonlinear behaviour. The aim of this work has been to assess the performance of two orthotropic and one isotropic hyper-elastic constitutive laws, providing an experimental-computational framework for the definition of reliable constitutive models of dermis tissue. Experimental, equi-biaxial stress-strain data obtained on human reticular dermis specimens have been exploited in order to extract, through a stochastic optimization procedure, constitutive parameters of three widely used constitutive laws: the Ogden, Holzapfel and Gasser-Ogden-Holzapfel (GOH) models. A set of specimen specific parameters and a set of best matching parameters, determined by simultaneously fitting all experimental stress-strain curves, have been obtained. The goodness of the selected laws has been assessed by means of FEM simulations performed in Abaqus (Simulia, Dessault Systèmes Inc.) which reproduce the actual specimen boundary conditions and geometry, rebuilt through an image segmentation process implemented in MATLAB (The MathWorks, Inc.). Models have been validated comparing experimental and numerical outcomes related to reference points on the specimen surface. In the preliminary fitting phase, Normalized Root Mean Square Error values were above 0.9 for the specimen-specific and above 0.54 for the best matching models. The comparison between numerical and experimental outcomes has highlighted the inadequacy of the isotropic constitutive law in reproducing the dermis behaviour, particularly at higher stretch levels. Errors obtained in the horizontal loading direction are lower than 40% for Holzapfel and GOH models, while the Ogden model reaches the 80%. Lower and more uniform errors occur in the orthogonal direction, which settles below 30% for the orthotropic laws, while it increases up to 40% in the isotropic case.