Vishwa Tiwari, R. D’Mello, Avinkrishnan Ambika Vijayachandran, Anthony Waas
Thin-walled cylindrical shell structures are revisited with the objective of increasing the axial load-carrying capacity. By using the postbuckling reserve of rectangular plates, polygonal shells are studied, which combines the response of a plate-like structure with a shell-like structure. These “plate-shells” are shown to be imperfection-insensitive for a range of polygonal shell designs. Furthermore, their collapse load exceeds the corresponding load for a circular cylindrical shell. These results are a significant departure from the well-known imperfection sensitivity in the axial compressive response of cylindrical shells.
{"title":"The axial compressive response of thin, elastic, polygonal shells","authors":"Vishwa Tiwari, R. D’Mello, Avinkrishnan Ambika Vijayachandran, Anthony Waas","doi":"10.1115/1.4064584","DOIUrl":"https://doi.org/10.1115/1.4064584","url":null,"abstract":"\u0000 Thin-walled cylindrical shell structures are revisited with the objective of increasing the axial load-carrying capacity. By using the postbuckling reserve of rectangular plates, polygonal shells are studied, which combines the response of a plate-like structure with a shell-like structure. These “plate-shells” are shown to be imperfection-insensitive for a range of polygonal shell designs. Furthermore, their collapse load exceeds the corresponding load for a circular cylindrical shell. These results are a significant departure from the well-known imperfection sensitivity in the axial compressive response of cylindrical shells.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"6 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139598425","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}
In the present work, an atomistic scale investigation is done on crystalline silicon to understand the effect of crack depth from the loading (pulling) boundary on the critical near-tip state of stress. For various depths of embedded cracks, the near-tip stress field has been calculated at the critical state just preceding crack blue propagation initiation. This atomistically calculated stress field is found to be quite close to those found using continuum linear elasticity. Thereafter, the critical stress intensity factor (SIF) is calculated for all cases by fitting the atomistically calculated normal stress over inverse square-rooted distance from the crack tip. It has been found that the closer the crack is located to the loading boundary (i.e. lesser depth), the lower is it's (locally calculated) critical SIF. This implies that it is easier to initiate crack propagation when the crack is located closer to the loading boundary. The claim is also strengthened by a similar observation for (globally calculated) boundary stresses at the critical state just before crack blue propagation initiation.
{"title":"Dependence of critical stress intensity factor on crack depth from the loading boundary of crystalline silicon","authors":"Ayan Basu, Gaurav Singh","doi":"10.1115/1.4064545","DOIUrl":"https://doi.org/10.1115/1.4064545","url":null,"abstract":"\u0000 In the present work, an atomistic scale investigation is done on crystalline silicon to understand the effect of crack depth from the loading (pulling) boundary on the critical near-tip state of stress. For various depths of embedded cracks, the near-tip stress field has been calculated at the critical state just preceding crack blue propagation initiation. This atomistically calculated stress field is found to be quite close to those found using continuum linear elasticity. Thereafter, the critical stress intensity factor (SIF) is calculated for all cases by fitting the atomistically calculated normal stress over inverse square-rooted distance from the crack tip. It has been found that the closer the crack is located to the loading boundary (i.e. lesser depth), the lower is it's (locally calculated) critical SIF. This implies that it is easier to initiate crack propagation when the crack is located closer to the loading boundary. The claim is also strengthened by a similar observation for (globally calculated) boundary stresses at the critical state just before crack blue propagation initiation.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"62 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139600445","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}
Rotating waves can be observed in structures with periodic conditions, such as cylinders and spheres. Compared with traveling waves and standing waves, rotating waves have received less attention. In this paper, an odd elastic dynamic model of the cylindrical shells is established, and the dispersion relation, traveling waves, and standing waves are investigated. The non-Hermitian rotating waves and single-handedness chiral standing spin waves are reported, which are novel dynamic phenomenon caused by odd elastic effects. Waves generally cannot propagate in passive materials with vanishingly small elastic modulus. However, a unidirectional wave with the highest cutoff frequency can occur in an odd elastic cylindrical shell with vanishingly small elastic modulus. For incompletely restrained end displacements, the odd elastic cylindrical shell can also generate a hybrid mode combining standing spin waves with unidirectional waves.
{"title":"Chiral Standing Spin Waves and Unidirectional Waves of Odd Elastic Cylindrical Shells","authors":"Andi Lai, Jiawei Zhou, C.W. Lim","doi":"10.1115/1.4064447","DOIUrl":"https://doi.org/10.1115/1.4064447","url":null,"abstract":"\u0000 Rotating waves can be observed in structures with periodic conditions, such as cylinders and spheres. Compared with traveling waves and standing waves, rotating waves have received less attention. In this paper, an odd elastic dynamic model of the cylindrical shells is established, and the dispersion relation, traveling waves, and standing waves are investigated. The non-Hermitian rotating waves and single-handedness chiral standing spin waves are reported, which are novel dynamic phenomenon caused by odd elastic effects. Waves generally cannot propagate in passive materials with vanishingly small elastic modulus. However, a unidirectional wave with the highest cutoff frequency can occur in an odd elastic cylindrical shell with vanishingly small elastic modulus. For incompletely restrained end displacements, the odd elastic cylindrical shell can also generate a hybrid mode combining standing spin waves with unidirectional waves.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"29 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139445072","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}
Dynamic buckling-induced delamination of nanofilms on substrates is a universal and essential phenomenon in nanoelectromechanical systems (NEMS). Van der Waals (vdWs) interactions play an important role in the dynamic buckling-induced delamination of nanofilms on substrates due to the interaction distances at nanoscale or even sub-nanoscale in NEMS. Therefore, it is interesting yet challenging to reveal the effect of intermolecular vdWs interactions on dynamic buckling-induced delamination of nanofilms on substrates. By considering sub-nanoscale dynamic boundary effects induced by intermolecular vdWs interactions, a parametric excitation nonlinear vibration model for dynamic buckling-induced delamination of nanofilms partly bonded on substrates is established. Effects of sub-nanoscale vdWs dynamic boundaries on transient and steady-state responses of dynamically delaminated nanofilms on substrates are analyzed. The sub-nanoscale vdWs dynamic boundaries lead the dynamic responses of delaminated-nanofilm/substrate systems very sensitive to initial conditions. The bending and shifting frequency response results demonstrated that the system nonlinearities can be greatly amplified by the sub-nanoscale vdWs dynamic boundary effect. Moreover, the spontaneous symmetry breaking and violent interfacial tearing/healing phenomena can be also triggered in the systems. Based on spontaneous symmetry breaking, a trans-scale relationship between nanofilm equilibrium positions and intermolecular vdWs interactions is established, which can provide a promising route for trans-scale measurements of molecular scale interfacial interactions. The work can also be helpful for the dynamic design of resonant NEMS devices based on nanofilm/substrate systems.
{"title":"Dynamic behaviors of delaminated nanofilms partly bonded on substrates with sub-nanoscale van der Waals dynamic boundaries","authors":"Zhi-Qi Dong, Kai-Ming Hu, Hui-Yue Lin, Xin-Lu Deng, Yi-Hang Xin, Guang Meng, Wen-Ming Zhang","doi":"10.1115/1.4064434","DOIUrl":"https://doi.org/10.1115/1.4064434","url":null,"abstract":"\u0000 Dynamic buckling-induced delamination of nanofilms on substrates is a universal and essential phenomenon in nanoelectromechanical systems (NEMS). Van der Waals (vdWs) interactions play an important role in the dynamic buckling-induced delamination of nanofilms on substrates due to the interaction distances at nanoscale or even sub-nanoscale in NEMS. Therefore, it is interesting yet challenging to reveal the effect of intermolecular vdWs interactions on dynamic buckling-induced delamination of nanofilms on substrates. By considering sub-nanoscale dynamic boundary effects induced by intermolecular vdWs interactions, a parametric excitation nonlinear vibration model for dynamic buckling-induced delamination of nanofilms partly bonded on substrates is established. Effects of sub-nanoscale vdWs dynamic boundaries on transient and steady-state responses of dynamically delaminated nanofilms on substrates are analyzed. The sub-nanoscale vdWs dynamic boundaries lead the dynamic responses of delaminated-nanofilm/substrate systems very sensitive to initial conditions. The bending and shifting frequency response results demonstrated that the system nonlinearities can be greatly amplified by the sub-nanoscale vdWs dynamic boundary effect. Moreover, the spontaneous symmetry breaking and violent interfacial tearing/healing phenomena can be also triggered in the systems. Based on spontaneous symmetry breaking, a trans-scale relationship between nanofilm equilibrium positions and intermolecular vdWs interactions is established, which can provide a promising route for trans-scale measurements of molecular scale interfacial interactions. The work can also be helpful for the dynamic design of resonant NEMS devices based on nanofilm/substrate systems.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"143 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387415","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}
We elaborate numerical approaches to calculate the rheological response of laminated glass beams, whose viscoelastic interlayer is modelled via fractional calculus. This mathematical description is very effective when the relaxation function of the polymer can be expressed by continuously connected branches of power-laws, as is the case for most materials used to laminate glass. The classical approach uses the Grünwald-Letnikov approximation of fractional derivatives, but it requires constant time steps, which would become very large to reasonably cover the entire observation time, thus losing accuracy. We propose to use the L1 algorithm with increasing time steps, which is well suited to the power law character of the relaxation function. This allows to follow the long-term creep response, providing a better approximation when needed. The method is implemented for beams laminated with viscolastic interlayers whose relaxation is described by four branches of power laws, to cover most practical cases. Numerical experiments shows its advantages over the Grünwald-Letnikov approach for characterizing the long-term structural response.
{"title":"Variable time steps in the numerical implementation of viscoelastic fractional models for laminated glass","authors":"Lorenzo Santi, G. Royer-Carfagni","doi":"10.1115/1.4064433","DOIUrl":"https://doi.org/10.1115/1.4064433","url":null,"abstract":"\u0000 We elaborate numerical approaches to calculate the rheological response of laminated glass beams, whose viscoelastic interlayer is modelled via fractional calculus. This mathematical description is very effective when the relaxation function of the polymer can be expressed by continuously connected branches of power-laws, as is the case for most materials used to laminate glass. The classical approach uses the Grünwald-Letnikov approximation of fractional derivatives, but it requires constant time steps, which would become very large to reasonably cover the entire observation time, thus losing accuracy. We propose to use the L1 algorithm with increasing time steps, which is well suited to the power law character of the relaxation function. This allows to follow the long-term creep response, providing a better approximation when needed. The method is implemented for beams laminated with viscolastic interlayers whose relaxation is described by four branches of power laws, to cover most practical cases. Numerical experiments shows its advantages over the Grünwald-Letnikov approach for characterizing the long-term structural response.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"8 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387257","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}
This study introduces a novel approach to analyze the stress and displacement fields around blunt notches in bi-material media, focusing on mode III loading conditions. The eigenfunction expansion method is used to derive a simplified yet accurate solution, satisfying the boundary conditions for bi-material blunt V-notches. The robustness of the proposed asymptotic solution is validated through several finite element analyses, encompassing a range of notched geometries such as blunt V-notches, VO-notches, and circular holes. Notably, it is demonstrated that when the notch tip radius approaches zero, the solution coincides with the existing sharp V-notch model, illustrating the robustness of the methodology.
本研究介绍了一种分析双材料介质钝缺口周围应力场和位移场的新方法，重点关注模式 III 载荷条件。采用特征函数展开法推导出一个简化但精确的解决方案，满足双材料钝V形缺口的边界条件。通过几种有限元分析，验证了所提出的渐近解的稳健性，包括一系列缺口几何形状，如钝 V 形缺口、VO 形缺口和圆孔。值得注意的是，当缺口尖端半径趋近于零时，该解决方案与现有的尖锐 V 型缺口模型相吻合，这说明了该方法的稳健性。
{"title":"Asymptotic stress field for the blunt and sharp notches in bi-material media under mode III loading","authors":"Amir Mohammad Mirzaei, A. Sapora, Pietro Cornetti","doi":"10.1115/1.4064323","DOIUrl":"https://doi.org/10.1115/1.4064323","url":null,"abstract":"This study introduces a novel approach to analyze the stress and displacement fields around blunt notches in bi-material media, focusing on mode III loading conditions. The eigenfunction expansion method is used to derive a simplified yet accurate solution, satisfying the boundary conditions for bi-material blunt V-notches. The robustness of the proposed asymptotic solution is validated through several finite element analyses, encompassing a range of notched geometries such as blunt V-notches, VO-notches, and circular holes. Notably, it is demonstrated that when the notch tip radius approaches zero, the solution coincides with the existing sharp V-notch model, illustrating the robustness of the methodology.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"145 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139172410","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}
Aeroelastic flutter is a dynamically complex phenomenon that has adverse and unstable effects on elastic structures. It is crucial to better predict the phenomenon of flutter within the scope of aircraft structures to improve upon the design of their wings. This review aims to establish fundamental guidelines for flutter analysis across subsonic, transonic, supersonic, and hypersonic flow regimes providing a thorough overview of established analytic, numerical, and reduced-order models as applicable to each flow regime. The review will shed light on the limitations and missing components within the previous literature on these flow regimes by highlighting the challenges involved in simulating flutter. Additionally, popular methods that employ the aforementioned analyses for optimizing wing structures under the effects of flutter, a subject currently garnering significant research attention, are also discussed. Our discussion offers new perspectives that encourages collaborative effort in the area of computational methods for flutter prediction and optimization.
{"title":"Overview of computational methods to predict flutter in aircraft","authors":"Ekaterina Antimirova, Jiyoung Jung, Zilan Zhang, Aaron Machuca, Grace X. Gu","doi":"10.1115/1.4064324","DOIUrl":"https://doi.org/10.1115/1.4064324","url":null,"abstract":"Aeroelastic flutter is a dynamically complex phenomenon that has adverse and unstable effects on elastic structures. It is crucial to better predict the phenomenon of flutter within the scope of aircraft structures to improve upon the design of their wings. This review aims to establish fundamental guidelines for flutter analysis across subsonic, transonic, supersonic, and hypersonic flow regimes providing a thorough overview of established analytic, numerical, and reduced-order models as applicable to each flow regime. The review will shed light on the limitations and missing components within the previous literature on these flow regimes by highlighting the challenges involved in simulating flutter. Additionally, popular methods that employ the aforementioned analyses for optimizing wing structures under the effects of flutter, a subject currently garnering significant research attention, are also discussed. Our discussion offers new perspectives that encourages collaborative effort in the area of computational methods for flutter prediction and optimization.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"102 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139171364","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}
Long-distance transport of a nanoparticle on a solid surface remains a challenge in nanotechnology. Here we design a nanoscale motor device for continuously transporting a nanoparticle on a beam surface. The device is composed of repeated units of clamped beams on which a harmonic excitation is applied to induce a gradient in atomic density on their surface, and such atomic density consequently creates a driving force on the nanoparticle attached on the device surface. The design requirements that should be satisfied by the device attributes are analytically derived, and the effect of the device attributes on the device transport performance is discussed. In addition, molecular dynamics simulations for a typical device of a graphene sheet transported on a silver beam are conducted to verify the analytical results. The proposed design provides a starting point for continuously transporting a nanoobject on a solid surface, and has a great potential in various applications such as nanomotors and molecular assembly lines.
{"title":"Continuous Transport of a Nanoparticle on a Solid Surface","authors":"Teng Zhang, Jiantao Leng, Tienchong Chang","doi":"10.1115/1.4064269","DOIUrl":"https://doi.org/10.1115/1.4064269","url":null,"abstract":"Long-distance transport of a nanoparticle on a solid surface remains a challenge in nanotechnology. Here we design a nanoscale motor device for continuously transporting a nanoparticle on a beam surface. The device is composed of repeated units of clamped beams on which a harmonic excitation is applied to induce a gradient in atomic density on their surface, and such atomic density consequently creates a driving force on the nanoparticle attached on the device surface. The design requirements that should be satisfied by the device attributes are analytically derived, and the effect of the device attributes on the device transport performance is discussed. In addition, molecular dynamics simulations for a typical device of a graphene sheet transported on a silver beam are conducted to verify the analytical results. The proposed design provides a starting point for continuously transporting a nanoobject on a solid surface, and has a great potential in various applications such as nanomotors and molecular assembly lines.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"49 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139179006","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}
Adhesive bonding of dissimilar materials introduces stress concentrations due to stiffness mismatch between the substrates, thereby exacerbating the peel and shear stresses leading to premature failures in single lap configurations. This work demonstrates that the stress distribution can be improved by decreasing the thickness of the stiffer substrate; and presents a structured approach to find the optimum thickness to improve overall joint performance. First, the critical stress components and critical locations in the single lap joint were identified for each mode of failure. Then, a minimax type optimization framework was developed using severity-weighted parameters for each critical stress component. Optimal thickness obtained from the proposed framework agreed with FEA based parametric studies within 10% variation. Overall, this approach can generate design charts and aid in efficient designs for multi-material joining.
{"title":"Substrate Thickness Optimization in Multi-material Single Lap Adhesive Joints","authors":"S. Kundurthi, Mahmood Haq","doi":"10.1115/1.4064268","DOIUrl":"https://doi.org/10.1115/1.4064268","url":null,"abstract":"Adhesive bonding of dissimilar materials introduces stress concentrations due to stiffness mismatch between the substrates, thereby exacerbating the peel and shear stresses leading to premature failures in single lap configurations. This work demonstrates that the stress distribution can be improved by decreasing the thickness of the stiffer substrate; and presents a structured approach to find the optimum thickness to improve overall joint performance. First, the critical stress components and critical locations in the single lap joint were identified for each mode of failure. Then, a minimax type optimization framework was developed using severity-weighted parameters for each critical stress component. Optimal thickness obtained from the proposed framework agreed with FEA based parametric studies within 10% variation. Overall, this approach can generate design charts and aid in efficient designs for multi-material joining.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"81 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139179242","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}
Stretchable inorganic electronics are of growing interest over the past decades due to their various attractive potential applications. The island-bridge structure is the most widely used structural design, where rigid inorganic devices (islands) and interconnects (bridges) are attached onto an elastomer substrate, and large deformations in the structure are accommodated by the large stretchability of the interconnects and the elastomer underneath them. Due to the large modulus mismatch of more than five orders of magnitude between the rigid island and elastomer substrate, there is a severe stress and strain concentration at the interface between the island and the substrate during large deformations, which may cause the interface fracture and delamination. In this work, the analytical solution of the interfacial shear and peel stress between the island and the substrate is derived to reveal the mechanism of interface fracture and agrees well with finite element analysis (FEA) results. A simple porous partition substrate design strategy is proposed to alleviate this stress and strain concentration at the boundary of the interface, where the porous region can undergo larger deformation due to the reduced stiffness of the material. FEA obtains the key parameters affecting the pore layout. The digital image correlation (DIC) experiment verifies the design strategy. The results show that, compared to the solid substrate, the porous partition substrate strategy can significantly reduce the maximum normal strain of the substrate around the island, thus effectively reducing the risk of structural interface failure.
{"title":"Design of porous partition elastomer substrates for the island-bridge structures in stretchable inorganic electronics","authors":"Hongwei Gao, Jiaxin Li, Zihao Wang, Zhaoguo Xue, Xianhong Meng","doi":"10.1115/1.4064267","DOIUrl":"https://doi.org/10.1115/1.4064267","url":null,"abstract":"Stretchable inorganic electronics are of growing interest over the past decades due to their various attractive potential applications. The island-bridge structure is the most widely used structural design, where rigid inorganic devices (islands) and interconnects (bridges) are attached onto an elastomer substrate, and large deformations in the structure are accommodated by the large stretchability of the interconnects and the elastomer underneath them. Due to the large modulus mismatch of more than five orders of magnitude between the rigid island and elastomer substrate, there is a severe stress and strain concentration at the interface between the island and the substrate during large deformations, which may cause the interface fracture and delamination. In this work, the analytical solution of the interfacial shear and peel stress between the island and the substrate is derived to reveal the mechanism of interface fracture and agrees well with finite element analysis (FEA) results. A simple porous partition substrate design strategy is proposed to alleviate this stress and strain concentration at the boundary of the interface, where the porous region can undergo larger deformation due to the reduced stiffness of the material. FEA obtains the key parameters affecting the pore layout. The digital image correlation (DIC) experiment verifies the design strategy. The results show that, compared to the solid substrate, the porous partition substrate strategy can significantly reduce the maximum normal strain of the substrate around the island, thus effectively reducing the risk of structural interface failure.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"59 27","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139180369","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}
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