Pub Date : 2025-08-01DOI: 10.1016/j.finmec.2025.100327
Ali Dadashi, Amin Asghaie, Mohammad Azadi
This study examines the microstructural and fatigue properties of AM60 magnesium alloy joints produced by rotary friction welding (RFW). Optical microscopy reveals significant microstructural changes, including grain refinement, reorientation of intermetallic phases, and redistribution of Mg17Al12 particles. The weld metal shows a dispersed needle-like intermetallic structure, while the heat-affected zone (HAZ) accumulates intermetallic phases at grain boundaries. Microhardness analysis indicates a high hardness value of 92.1 Hv at the weld interface, decreasing towards the base metal (BM) with hardness values between 50–60 Hv. Fatigue behavior studies demonstrate that higher interface angles reduce fatigue lifetime, with the 42° conical specimen showing the best performance. Fractography reveals a transgranular quasi-cleavage fracture mode, with cracks nucleating at the weld interface. Additionally, regression analysis was performed, and the suggested model was well-fitted. The study underscores the complex interplay of welding parameters, microstructure, and mechanical properties, offering insights for optimizing welding processes to enhance fatigue resistance of welded magnesium alloy joints.
{"title":"Evaluation of high-cycle bending fatigue properties and fracture behaviors in AM60 magnesium alloy joints by friction welding","authors":"Ali Dadashi, Amin Asghaie, Mohammad Azadi","doi":"10.1016/j.finmec.2025.100327","DOIUrl":"10.1016/j.finmec.2025.100327","url":null,"abstract":"<div><div>This study examines the microstructural and fatigue properties of AM60 magnesium alloy joints produced by rotary friction welding (RFW). Optical microscopy reveals significant microstructural changes, including grain refinement, reorientation of intermetallic phases, and redistribution of Mg<sub>17</sub>Al<sub>12</sub> particles. The weld metal shows a dispersed needle-like intermetallic structure, while the heat-affected zone (HAZ) accumulates intermetallic phases at grain boundaries. Microhardness analysis indicates a high hardness value of 92.1 Hv at the weld interface, decreasing towards the base metal (BM) with hardness values between 50–60 Hv. Fatigue behavior studies demonstrate that higher interface angles reduce fatigue lifetime, with the 42° conical specimen showing the best performance. Fractography reveals a transgranular quasi-cleavage fracture mode, with cracks nucleating at the weld interface. Additionally, regression analysis was performed, and the suggested model was well-fitted. The study underscores the complex interplay of welding parameters, microstructure, and mechanical properties, offering insights for optimizing welding processes to enhance fatigue resistance of welded magnesium alloy joints.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"20 ","pages":"Article 100327"},"PeriodicalIF":3.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-17DOI: 10.1016/j.finmec.2025.100324
Koh-hei Nitta, Sakina Tatsuta
The moduli obtained from the three-point bending tests for beam and plate specimens are apparently higher than the tensile Young’s modulus. For the beam specimen, a volumetric compression mode is observed in the inner zone of the bent specimen, whereas a uniaxial tension mode is observed in the outer zone. The flexural modulus in beam bending can be determined using the bimodular model, where the moduli of the innermost and outermost layers represent the bulk and tensile moduli, respectively. On the other hand, plate bending results in a strip-biaxial deformation during bending, with the bending modulus obtained from the cylindrical deformation. The principal factor influencing the flexural moduli of both specimens is the Poisson’s ratio.
{"title":"Bending deformation of polyethylene solid","authors":"Koh-hei Nitta, Sakina Tatsuta","doi":"10.1016/j.finmec.2025.100324","DOIUrl":"10.1016/j.finmec.2025.100324","url":null,"abstract":"<div><div>The moduli obtained from the three-point bending tests for beam and plate specimens are apparently higher than the tensile Young’s modulus. For the beam specimen, a volumetric compression mode is observed in the inner zone of the bent specimen, whereas a uniaxial tension mode is observed in the outer zone. The flexural modulus in beam bending can be determined using the bimodular model, where the moduli of the innermost and outermost layers represent the bulk and tensile moduli, respectively. On the other hand, plate bending results in a strip-biaxial deformation during bending, with the bending modulus obtained from the cylindrical deformation. The principal factor influencing the flexural moduli of both specimens is the Poisson’s ratio.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"20 ","pages":"Article 100324"},"PeriodicalIF":3.2,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-13DOI: 10.1016/j.finmec.2025.100322
Vigneshwaran Karupaiah , Venkateshwaran Narayanan , Elif Kaynak , Vigneshwaran Shanmugam , Oisik Das
This study introduces a novel hexagonal honeycomb lattice design incorporating integrated diagonal struts, developed to enhance compression strength and energy absorption in 3D-printed polymer structures. Five distinct lattice configurations were fabricated using polylactic acid (PLA) filament and evaluated through uniaxial compression testing. The results showed that Lattice 5, which features a hexagonal unit cell with diagonal struts from top left to bottom right, had the highest compression strength of 45.78 MPa and absorbed 14,406 J of energy. In comparison, Lattice 1, with a regular hexagonal unit cell, had 15 % lower compression strength and 20 % lower energy absorption. Analytical models based on honeycomb geometry and PLA material properties were used to predict how the structures would deform. Finite element analysis (FEA) was also conducted to study the deformation under dynamic loading, with Lattice 5 proving to be the most efficient design. The diagonal struts in Lattice 5 helped to redistribute the load more evenly, reducing stress concentrations and allowing for a more gradual deformation. The FEA results matched the experimental data closely, confirming the accuracy of the predictions. These findings offer useful insights for improving lattice structures for applications that require high performance in terms of both structural strength and energy absorption.
{"title":"Experimental and numerical investigation of diagonally reinforced 3D-architected polymer honeycomb lattice structures fabricated via FDM using PLA","authors":"Vigneshwaran Karupaiah , Venkateshwaran Narayanan , Elif Kaynak , Vigneshwaran Shanmugam , Oisik Das","doi":"10.1016/j.finmec.2025.100322","DOIUrl":"10.1016/j.finmec.2025.100322","url":null,"abstract":"<div><div>This study introduces a novel hexagonal honeycomb lattice design incorporating integrated diagonal struts, developed to enhance compression strength and energy absorption in 3D-printed polymer structures. Five distinct lattice configurations were fabricated using polylactic acid (PLA) filament and evaluated through uniaxial compression testing. The results showed that Lattice 5, which features a hexagonal unit cell with diagonal struts from top left to bottom right, had the highest compression strength of 45.78 MPa and absorbed 14,406 J of energy. In comparison, Lattice 1, with a regular hexagonal unit cell, had 15 % lower compression strength and 20 % lower energy absorption. Analytical models based on honeycomb geometry and PLA material properties were used to predict how the structures would deform. Finite element analysis (FEA) was also conducted to study the deformation under dynamic loading, with Lattice 5 proving to be the most efficient design. The diagonal struts in Lattice 5 helped to redistribute the load more evenly, reducing stress concentrations and allowing for a more gradual deformation. The FEA results matched the experimental data closely, confirming the accuracy of the predictions. These findings offer useful insights for improving lattice structures for applications that require high performance in terms of both structural strength and energy absorption.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"20 ","pages":"Article 100322"},"PeriodicalIF":3.2,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-28DOI: 10.1016/j.finmec.2025.100321
Baohua Ji
Mechanobiology is now a widely accepted field of science at the interface of biology, medicine, engineering, and physics. Mechanomedicine, however, is an emerging field of diagnosing and treating diseases based on the knowledge obtained from mechanobiological studies. It proposes a new concept of diagnosis and treatment of diseases using the mechanical concept, theories, and approaches. But the question how we employ the mechanical factors to diagnose and treat the diseases is far from being addressed. Here, based on our recent studies on the tensional homeostasis, we try to give some clues for the endeavor of answering these questions. Diseases are thought as the results of significant deviation of function/structure of life from the corresponding homeostasis at different length scales, including the tensional homeostasis. If we can properly tune the value of tension in the living organisms, then it creates a new way of treating the diseases.
{"title":"Mechanobiology and mechanomedicine: Tuning the tension in the life","authors":"Baohua Ji","doi":"10.1016/j.finmec.2025.100321","DOIUrl":"10.1016/j.finmec.2025.100321","url":null,"abstract":"<div><div>Mechanobiology is now a widely accepted field of science at the interface of biology, medicine, engineering, and physics. Mechanomedicine, however, is an emerging field of diagnosing and treating diseases based on the knowledge obtained from mechanobiological studies. It proposes a new concept of diagnosis and treatment of diseases using the mechanical concept, theories, and approaches. But the question how we employ the mechanical factors to diagnose and treat the diseases is far from being addressed. Here, based on our recent studies on the tensional homeostasis, we try to give some clues for the endeavor of answering these questions. Diseases are thought as the results of significant deviation of function/structure of life from the corresponding homeostasis at different length scales, including the tensional homeostasis. If we can properly tune the value of tension in the living organisms, then it creates a new way of treating the diseases.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"20 ","pages":"Article 100321"},"PeriodicalIF":3.2,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-25DOI: 10.1016/j.finmec.2025.100315
Stéphane Grange, David Bertrand
This paper presents a new co-rotational shell element based on quaternion algebra as a means of parameterizing large rotations. The co-rotational framework is suitable for beam or shell elements and has been extensively studied in the literature. It is based on a decomposition between rigid body motion and local displacements that generate deformation.
The advantage of this framework lies in the fact that the internal element defined in the co-rotational frame can be derived from a library of elements (possibly in small or large deformations and even with material nonlinearities).
The present formulation constitutes an extension of a previous work devoted to a beam finite element using quaternion algebra and applied to shell finite elements. Quaternion algebra is used throughout the kinematic chain, and such parameterization offers an alternative to classical co-rotational formulations. The model is developed within the framework of incremental rotation formulations. Once the decomposition between rigid body motion and local displacements has been performed, the principle of virtual work is introduced to calculate the element response projected onto large displacements and rotations.
The adopted methodology is then exposed for a three-node triangular shell element. For the sake of simplicity and to demonstrate the capabilities of the co-rotational frame with quaternions, DKT (bending) and OPT (membrane) triangular shell elements with small strains are chosen as the internal element.
One of the main advantages of using quaternions for parameterization lies in their efficiency for dynamic applications, as they allow for a relative straightforward computation of gyroscopic terms. The numerical simulations show a stable mechanical energy of the systems and a good numerical stability.
Ten distinct static and dynamic numerical applications are also presented and compared to the literature.
{"title":"Co-rotational 3D shell element using quaternion algebra to account for large rotations: Static and dynamic applications","authors":"Stéphane Grange, David Bertrand","doi":"10.1016/j.finmec.2025.100315","DOIUrl":"10.1016/j.finmec.2025.100315","url":null,"abstract":"<div><div>This paper presents a new co-rotational shell element based on quaternion algebra as a means of parameterizing large rotations. The co-rotational framework is suitable for beam or shell elements and has been extensively studied in the literature. It is based on a decomposition between rigid body motion and local displacements that generate deformation.</div><div>The advantage of this framework lies in the fact that the internal element defined in the co-rotational frame can be derived from a library of elements (possibly in small or large deformations and even with material nonlinearities).</div><div>The present formulation constitutes an extension of a previous work devoted to a beam finite element using quaternion algebra and applied to shell finite elements. Quaternion algebra is used throughout the kinematic chain, and such parameterization offers an alternative to classical co-rotational formulations. The model is developed within the framework of incremental rotation formulations. Once the decomposition between rigid body motion and local displacements has been performed, the principle of virtual work is introduced to calculate the element response projected onto large displacements and rotations.</div><div>The adopted methodology is then exposed for a three-node triangular shell element. For the sake of simplicity and to demonstrate the capabilities of the co-rotational frame with quaternions, DKT (bending) and OPT (membrane) triangular shell elements with small strains are chosen as the internal element.</div><div>One of the main advantages of using quaternions for parameterization lies in their efficiency for dynamic applications, as they allow for a relative straightforward computation of gyroscopic terms. The numerical simulations show a stable mechanical energy of the systems and a good numerical stability.</div><div>Ten distinct static and dynamic numerical applications are also presented and compared to the literature.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"20 ","pages":"Article 100315"},"PeriodicalIF":3.2,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-15DOI: 10.1016/j.finmec.2025.100320
Francisco J. Nieves , Ana Bayón , Félix Salazar , Francisco Gascón
The transverse vibration of a bar is studied by applying the Bernoulli-Euler beam theory. The bar is placed between the platens of a hydraulic press that applies compressive stress. When the bar vibrates, its ends slide over the platens with dry friction. Boundary conditions appropriate to the existence of friction are proposed. Once the homogeneous equation of motion is solved analytically, a particular solution is obtained through elementary trigonometric series. The sum of these solutions provides the general solution that shows the movement of all the bar points. The movement is divided into successive stages. The displacement of the bar points as a function of time is calculated numerically. It is demonstrated that there is a sudden change in the shape of vibrating when a specific number of semi-oscillations is reached, going from a behaviour of sliding ends to another of fixed ends. Criteria are proposed to estimate the circumstances in which the partial stop of the vibration occurs, as well as a change in the vibration mode and its frequency.
{"title":"Transverse vibration of an axially compressed bar with dry friction at its ends","authors":"Francisco J. Nieves , Ana Bayón , Félix Salazar , Francisco Gascón","doi":"10.1016/j.finmec.2025.100320","DOIUrl":"10.1016/j.finmec.2025.100320","url":null,"abstract":"<div><div>The transverse vibration of a bar is studied by applying the Bernoulli-Euler beam theory. The bar is placed between the platens of a hydraulic press that applies compressive stress. When the bar vibrates, its ends slide over the platens with dry friction. Boundary conditions appropriate to the existence of friction are proposed. Once the homogeneous equation of motion is solved analytically, a particular solution is obtained through elementary trigonometric series. The sum of these solutions provides the general solution that shows the movement of all the bar points. The movement is divided into successive stages. The displacement of the bar points as a function of time is calculated numerically. It is demonstrated that there is a sudden change in the shape of vibrating when a specific number of semi-oscillations is reached, going from a behaviour of sliding ends to another of fixed ends. Criteria are proposed to estimate the circumstances in which the partial stop of the vibration occurs, as well as a change in the vibration mode and its frequency.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"20 ","pages":"Article 100320"},"PeriodicalIF":3.2,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-01DOI: 10.1016/j.finmec.2025.100314
Hussain Gharehbaghi, Mehdi Aghaei
In this research, the strength analysis and life evaluation of a steam turbine rotor were studied. The effects related to low cycle fatigue and creep were investigated according to ASME BPVC SECTION III-NH. For this purpose, numerical analyses were performed considering transient and steady-state thermal and mechanical loadings. Transient response was used to obtain temperature, stress, and strain distributions as functions of time in low-cycle fatigue analysis, and steady-state response was used for the evaluation of creep effects. Finally, the number of allowed Equivalent Operating Hours (EOH) was determined. Using this method, the turbine start-up curves were modified in such a way that the life provided for the turbine is in the safe area and the fastest possible start-up occurs.
{"title":"Investigation of creep-fatigue interaction in steam turbine rotor","authors":"Hussain Gharehbaghi, Mehdi Aghaei","doi":"10.1016/j.finmec.2025.100314","DOIUrl":"10.1016/j.finmec.2025.100314","url":null,"abstract":"<div><div>In this research, the strength analysis and life evaluation of a steam turbine rotor were studied. The effects related to low cycle fatigue and creep were investigated according to ASME BPVC SECTION III-NH. For this purpose, numerical analyses were performed considering transient and steady-state thermal and mechanical loadings. Transient response was used to obtain temperature, stress, and strain distributions as functions of time in low-cycle fatigue analysis, and steady-state response was used for the evaluation of creep effects. Finally, the number of allowed Equivalent Operating Hours (EOH) was determined. Using this method, the turbine start-up curves were modified in such a way that the life provided for the turbine is in the safe area and the fastest possible start-up occurs.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"19 ","pages":"Article 100314"},"PeriodicalIF":3.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144098817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-01DOI: 10.1016/j.finmec.2025.100313
Qiyue Liu , Jintian Liu , Steven Kutschke , Viktoria Kosmalla , David Schürenkamp , Nils Goseberg , Markus Böl
Wave attenuation by vegetation, such as in salt marshes or on coastal dunes, is an environmentally friendly measure for erosion control and coastal protection. A particular factor here is the seasonal variation, both on the plant side and on the wave side. Plants have different mechanical properties and physiology (including morphology, cellular and molecular characteristics) depending on the season. Mechanical experiments are essential to better evaluate the erosion protection provided by coastal vegetation depending on the season, and to generate mechanical properties for corresponding simulations that can predict the vegetation’s resistance to waves, which in turn would enable optimised planting. For this purpose, different bending experiments were performed on salt marsh culm sections collected at different times in the year. Based on the cross-sectional morphology and force–deflection curves, the non-linear structural and material behaviour of the culm section is obtained using the inverse finite element method. The results show that the upper part of the grass culm behaves much more softly than the middle and lower parts, while the culm has a much stiffer material behaviour in winter (March) than in summer (June and September). In addition, this study found a negative correlation between Young’s modulus and second moment of inertia, suggesting an adaptive trade-off between structural and material properties under different growth conditions. The data obtained are important for a general understanding of the seasonal behaviour of salt marsh vegetation. On the other hand, they are particularly valuable for modelling of coastal erosion, vegetation patches or culm-fluid interactions.
{"title":"Seasonal mechanical behaviour of Elymus spec. for the assessment of ecosystem services","authors":"Qiyue Liu , Jintian Liu , Steven Kutschke , Viktoria Kosmalla , David Schürenkamp , Nils Goseberg , Markus Böl","doi":"10.1016/j.finmec.2025.100313","DOIUrl":"10.1016/j.finmec.2025.100313","url":null,"abstract":"<div><div>Wave attenuation by vegetation, such as in salt marshes or on coastal dunes, is an environmentally friendly measure for erosion control and coastal protection. A particular factor here is the seasonal variation, both on the plant side and on the wave side. Plants have different mechanical properties and physiology (including morphology, cellular and molecular characteristics) depending on the season. Mechanical experiments are essential to better evaluate the erosion protection provided by coastal vegetation depending on the season, and to generate mechanical properties for corresponding simulations that can predict the vegetation’s resistance to waves, which in turn would enable optimised planting. For this purpose, different bending experiments were performed on salt marsh culm sections collected at different times in the year. Based on the cross-sectional morphology and force–deflection curves, the non-linear structural and material behaviour of the culm section is obtained using the inverse finite element method. The results show that the upper part of the grass culm behaves much more softly than the middle and lower parts, while the culm has a much stiffer material behaviour in winter (March) than in summer (June and September). In addition, this study found a negative correlation between Young’s modulus and second moment of inertia, suggesting an adaptive trade-off between structural and material properties under different growth conditions. The data obtained are important for a general understanding of the seasonal behaviour of salt marsh vegetation. On the other hand, they are particularly valuable for modelling of coastal erosion, vegetation patches or culm-fluid interactions.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"19 ","pages":"Article 100313"},"PeriodicalIF":3.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A passive vibration control study has been carried out to understand the nature of fluid structure interaction on control rods. Further to identify the possible ways to preserve the structural integrity by isolating the impact of vibration. In regards, by employing multiple control tubes to assess the characteristics of induced vibration and flow dynamics over a fuel cell structures in different orientation at a subcritical Reynolds number (Re=18,685) has been proposed. An experimental and numerical investigation has been performed to understand the influence of control tubes over the test structure. The computational study has been performed by employing the Large Eddy Simulation technique to estimate the flow characteristics and it dynamics over the test structures. Similarly, the experimental investigation also focussed on understanding nature of control rods subjected fluid flow with an influence of control tubes. In this study nine different cases were taken into consideration for the better understanding on the proposed idea. It is mainly focussed on the amplitude response with respect to the force coefficients. Further, it examines the near wake flow structure, instantaneous flow field, mean flow field, turbulent intensity, vortex length and mean pressure distribution for all the considered cases. The swirling flow is identified to be more significant in the development of sloping three-dimensional flow structures with a low-frequency force coefficient despite the induced high-frequency force coefficient resulted due to the Karman vortices. In addition, the perfectly organized vortices observed for a larger value of wave sharpness reveals a noteworthy influence on the inconsistency in the lift force. Only a minor peak raise in the amplitude response for the case 4 and case 5 is identified. It is because of the control tubes positioned in the upstream condition causes a blockade effect on the excessive forces on the tube structures, and reduces the displacement effects due to the flow impact directly on the control rods structures. At last, the base pressure coefficient is observed to be along with the stagnation point at .
{"title":"Sustainable passive vibration control of fuel cells on fluid structure interaction","authors":"Karthik Selva Kumar Karuppasamy , Brintha Ramachandran , Aruna Devi Karuppasamy , Balaji P․S․ , Krishna Kumar Jaiswal , Sangmesh B","doi":"10.1016/j.finmec.2025.100316","DOIUrl":"10.1016/j.finmec.2025.100316","url":null,"abstract":"<div><div>A passive vibration control study has been carried out to understand the nature of fluid structure interaction on control rods. Further to identify the possible ways to preserve the structural integrity by isolating the impact of vibration. In regards, by employing multiple control tubes to assess the characteristics of induced vibration and flow dynamics over a fuel cell structures in different orientation at a subcritical Reynolds number (<em>Re</em>=18,685) has been proposed. An experimental and numerical investigation has been performed to understand the influence of control tubes over the test structure. The computational study has been performed by employing the Large Eddy Simulation technique to estimate the flow characteristics and it dynamics over the test structures. Similarly, the experimental investigation also focussed on understanding nature of control rods subjected fluid flow with an influence of control tubes. In this study nine different cases were taken into consideration for the better understanding on the proposed idea. It is mainly focussed on the amplitude response with respect to the force coefficients. Further, it examines the near wake flow structure, instantaneous flow field, mean flow field, turbulent intensity, vortex length and mean pressure distribution for all the considered cases. The swirling flow is identified to be more significant in the development of sloping three-dimensional flow structures with a low-frequency force coefficient despite the induced high-frequency force coefficient resulted due to the Karman vortices. In addition, the perfectly organized vortices observed for a larger value of wave sharpness reveals a noteworthy influence on the inconsistency in the lift force. Only a minor peak raise in the amplitude response for the case 4 and case 5 is identified. It is because of the control tubes positioned in the upstream condition causes a blockade effect on the excessive forces on the tube structures, and reduces the displacement effects due to the flow impact directly on the control rods structures. At last, the base pressure coefficient is observed to be <span><math><mrow><mi>c</mi><mi>p</mi><mo>≈</mo><mn>0.96</mn></mrow></math></span> along with the stagnation point at <span><math><mrow><mi>θ</mi><mo>≈</mo><msup><mrow><mn>71</mn></mrow><mn>0</mn></msup></mrow></math></span>.</div></div>","PeriodicalId":93433,"journal":{"name":"Forces in mechanics","volume":"19 ","pages":"Article 100316"},"PeriodicalIF":3.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-21DOI: 10.1016/j.finmec.2025.100312
Diem Dang Nguyen , Hien Duy Ta
This study presents the development of the stochastic finite element method (SFEM) to investigate the random free vibrations of beams with three-dimensional (3D) random field of material properties. Material properties, such as mass density and Young's modulus, are modeled as 3D stationary univariate random fields, with their correlations considered in the dynamic analysis. The random material fields are discretized into random variables using the weighted integral method combined with the perturbation technique to obtain a first-order approximation of the eigenvalues of free vibration. Statistical quantities, including mean, variance, and coefficient of variation (COV), of the eigenvalues are derived. Monte Carlo simulations (MCs), based on standard FEM and the spectral representation method for stochastic fields, are employed to validate the SFEM solution. The three-dimensional randomness of material properties significantly affects the random dynamic response of the structure. Results reveal that as the correlation distance increases, the dispersion of the eigenvalues around the expected value also increases. A perfect positive correlation between the 3D random fields of Young's modulus and mass density results in a smaller COV, whereas a perfect negative correlation leads to a larger COV. As the correlation distance approaches infinity, the COV approaches the total standard deviation for a negative correlation, while it becomes negligible for a positive correlation. For independent random fields, the COV converges to approximately 70 % of the total standard deviation. The nearly linear relationship between COV and standard deviation enables the prediction of the random response of the structure once the material property randomness is defined.
本文介绍了随机有限元法（SFEM）的发展，用于研究具有材料特性三维随机场的梁的随机自由振动。材料性能，如质量密度和杨氏模量，被建模为三维平稳的单变量随机场，并在动态分析中考虑它们的相关性。采用加权积分法结合微扰技术将随机材料场离散为随机变量，得到自由振动特征值的一阶近似。导出了特征值的统计量，包括平均值、方差和变异系数。采用蒙特卡罗模拟（Monte Carlo simulation, MCs），基于标准有限元法和随机场谱表示法，对SFEM解进行了验证。材料性能的三维随机性对结构的随机动力响应有显著影响。结果表明，随着相关距离的增大，特征值在期望值周围的离散度也增大。三维随机场的杨氏模量与质量密度的正相关关系导致COV减小，负相关关系导致COV增大。当相关距离趋近于无穷大时，对于负相关，COV趋近于总标准差，而对于正相关，COV变得可以忽略不计。对于独立随机场，COV收敛到总标准差的约70%。COV与标准差之间的近似线性关系可以在确定材料特性随机性后预测结构的随机响应。
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