Journal of Applied Mechanics最新文献_第6页

Unequal-biaxial taut states of electro-active polymeric composites 电活性聚合物复合材料的非等轴绷紧状态

Journal of Applied Mechanics Pub Date : 2023-12-12 DOI: 10.1115/1.4064256

Sankalp Gour, Deepak Kumar

{"title":"Unequal-biaxial taut states of electro-active polymeric composites","authors":"Sankalp Gour, Deepak Kumar","doi":"10.1115/1.4064256","DOIUrl":"https://doi.org/10.1115/1.4064256","url":null,"abstract":"Existing studies on wrinkling, an instability phenomenon commonly observed on electro-active polymers (EAP), have largely ignored the unequal-biaxial taut states, focusing instead on the equal-biaxial deformations of such a material class. EAP-based soft actuators, primarily used in soft robotics, frequently exhibit a variety of instabilities, which may adversely affect their functioning and trigger device failure. Conversely, wrinkles can be utilized proactively in specific applications that necessitate an intentional transformation in surface morphology along with functional particle reinforcement on EAP composites. The dielectric elastomer is a promising EAP material class for the same, often filled with functional particles to improve its electromechanical performance. This paper theoretically develops a continuum physics-based unequal-biaxial deformation model incorporating the classical tension field theory to predict the thresholds on the taut domains in the plane of principal stretches. The model solution ties an unanswered ideal remark on the deviations of taut states with the biaxiality ratio of unequal-biaxially deformed wrinkle appearance in EAP composites. The proposed model solution may aid in designing next-generation soft robotic systems by offering guidelines for the wrinkling control of EAP composites.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"6 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139182981","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}

引用次数: 0

Uncoupling of Linear Multi-degree of Freedom Damped Gyroscopic Potential Systems 线性多自由度阻尼陀螺势能系统的解耦

Journal of Applied Mechanics Pub Date : 2023-11-23 DOI: 10.1115/1.4064127

F. Udwadia, R. Bulatović

引用次数: 0

A comment on ‘The trousers fracture test for viscoelastic elastomers’, JAM 90(7), 071010, 2023 对 "粘弹性弹性体的裤管断裂测试 "的评论，《机械工程学报》90（7），071010，2023 年

Journal of Applied Mechanics Pub Date : 2023-11-23 DOI: 10.1115/1.4064126

Michele Ciavarella

{"title":"A comment on ‘The trousers fracture test for viscoelastic elastomers’, JAM 90(7), 071010, 2023","authors":"Michele Ciavarella","doi":"10.1115/1.4064126","DOIUrl":"https://doi.org/10.1115/1.4064126","url":null,"abstract":"The Rivlin-Thomas classical energy balance model for tearing tests suggests that the fracture energy G is proportional to the work of the external load in the legs (potential energy), for not too large stretches in the legs, so the increase of G with loading rate is observed or measured, but not really explained by the model. Shrimali & Lopez-Pamies (SLP) have recently built a theory on viscoelastic fracture from recent experimental evidence of a critical (stretch rate independent) stretch on nucleation of cracks in pure shear tests. The theory in other words incorporates this evidence in an otherwise energy based criterion. In the paper “The trousers fracture test for viscoelastic elastomers”, JAM 90(7), 071010, 2023, they seem to obtain the critical (stretch rate independent) stretch condition for the case of trouser tests (applying their theory from a long enough crack) both in nucleation and steady state propagation. This outcome seems reasonable since for a linear material, looking at the elastic limit cases of very slow and very fast rate it would produce an increase of the load, and hence of the fracture energy, proportional to the increase of the modulus, which is in line with what has been found experimentally, although possibly in contrast with classical theories.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139245628","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}

引用次数: 0

Mechanical Metamaterials Fabricated from Self-assembly: A Perspective 自组装制造的机械超材料：透视

Journal of Applied Mechanics Pub Date : 2023-11-12 DOI: 10.1115/1.4064144

Hanxun Jin, Horacio D. Espinosa

引用次数: 0

Modeling Atomistic Dynamic Fracture Mechanisms Using a Progressive Transformer Diffusion Model. 用渐进变压器扩散模型建模原子动态断裂机制。

IF 2.6

Journal of Applied Mechanics Pub Date : 2022-12-01 Epub Date: 2022-10-06 DOI: 10.1115/1.4055730

Markus J Buehler

引用次数: 20

Multidimensional Mechanics of Three-Dimensional Printed and Micro-Architectured Scaffolds. 三维打印和微结构支架的多维力学。

IF 2.6

Journal of Applied Mechanics Pub Date : 2021-10-01 Epub Date: 2021-06-08 DOI: 10.1115/1.4051182

Pooya Niksiar, Zhaoxu Meng, Michael M Porter

{"title":"Multidimensional Mechanics of Three-Dimensional Printed and Micro-Architectured Scaffolds.","authors":"Pooya Niksiar, Zhaoxu Meng, Michael M Porter","doi":"10.1115/1.4051182","DOIUrl":"https://doi.org/10.1115/1.4051182","url":null,"abstract":"Mechanical properties of porous materials depend on their micro-architectural characteristics. Freeze casting is an effective method to fabricate micro-architectured porous scaffolds. Three key characteristics generated during freeze casting are wall thickness, number of domains at the cross-section, and transverse bridges connecting adjacent walls. To specifically study the effect of these structural characteristics on the mechanics and anisotropic compressive properties of scaffolds, we utilize additive manufacturing, i.e., 3D printing, to fabricate strictly designed cubic scaffolds with varying one characteristic at a time. We then compare strength, toughness, resilience, stiffness, and strain to failure in three orthogonal directions of the scaffolds, including longitudinal and transverse directions. To compare these multidimensional mechanics in a single diagram, we use a previously developed radar chart method to evaluate different scaffolds and unravel the effect of the structural characteristics. We find that the multidimensional mechanics can be effectively tuned by the micro-architectural characteristics. Notably, the buckling resistance of the scaffolds depends on all three structural characteristics. Our results show that an increased number of domains leads to enhanced toughness in all three directions. Increasing wall thickness leads to enhanced mechanical properties but comes at the price of losing small-sized pores, which is not favored for certain applications. In addition, adding transverse bridges increase not only the transverse strength of the scaffolds but also the longitudinal strength as they also enhance the buckling resistance. Our study provides important insights into the structure-property relationships of 3D-printed micro-architectured porous scaffolds.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"88 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8613766/pdf/nihms-1755733.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39673344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Magnetic Forces Enable Control of Biological Processes In Vivo. 磁力可以控制体内的生物过程。

IF 2.6

Journal of Applied Mechanics Pub Date : 2021-03-01 Epub Date: 2021-01-12 DOI: 10.1115/1.4049331

Gang Bao

{"title":"Magnetic Forces Enable Control of Biological Processes In Vivo.","authors":"Gang Bao","doi":"10.1115/1.4049331","DOIUrl":"https://doi.org/10.1115/1.4049331","url":null,"abstract":"Similar to mechanical forces that can induce profound biological effects, magnetic fields can have a broad range of implications to biological systems, from magnetoreception that allows an organism to detect a magnetic field to perceive direction, altitude, or location, to the use of heating induced by magnetic field for altering neuron activity. This review focuses on the application of magnetic forces generated by magnetic iron oxide nanoparticles (MIONs), which can also provide imaging contrast and mechanical/thermal energy in response to an external magnetic field, a special feature that distinguishes MIONs from other nanomaterials. The magnetic properties of MIONs offer unique opportunities for enabling control of biological processes under different magnetic fields. Here, we describe the approaches of utilizing the forces generated by MIONs under an applied magnetic field to control biological processes and functions, including the targeting of drug molecules to a specific tissue, increasing the vessel permeability for improving drug delivery, and activating a particular viral vector for spatial control of genome editing in vivo. The opportunities of using nanomagnets for a broad range of biomedical applications are briefly discussed.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"88 3","pages":"030801"},"PeriodicalIF":2.6,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208485/pdf/jam_88_3_030801.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39036691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Spontaneous Negative Entropy Increments in Granular Flows. 颗粒流中的自发负熵增量。

IF 2.6

Journal of Applied Mechanics Pub Date : 2021-03-01 Epub Date: 2020-12-04 DOI: 10.1115/1.4049184

Rossella Laudani, Martin Ostoja-Starzewski

{"title":"Spontaneous Negative Entropy Increments in Granular Flows.","authors":"Rossella Laudani, Martin Ostoja-Starzewski","doi":"10.1115/1.4049184","DOIUrl":"https://doi.org/10.1115/1.4049184","url":null,"abstract":"The entropy inequality, commonly taken as an axiom of continuum mechanics, is found to be spontaneously violated in macroscopic granular media undergoing collisional dynamics. The result falls within the fluctuation theorem of nonequilibrium thermodynamics, which is known to replace the Second Law for finite systems. This phenomenon amounts to the system stochastically displaying negative increments of entropy. The focus is on granular media in Couette flows, consisting of monosized circular disks (with 10 to 104 disks of diameters 0.01 m to 1 m) with frictional-Hookean contacts simulated by molecular dynamics accounting for micropolar effects. Overall, it is determined that the probability of negative entropy increments diminishes with the Eulerian velocity gradient increasing, while it tends to increase in a sigmoidal fashion with the Young modulus of disks increasing. This behavior is examined for a very wide range of known materials: from the softest polymers to the stiffest (i.e., carbyne). The disks' Poisson ratio is found to have a weak effect on the probability of occurrence of negative entropy increments.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"88 3","pages":"031010"},"PeriodicalIF":2.6,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208484/pdf/jam_88_3_031010.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39036692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Scaling Effects on the Residual Thermomechanical Stress During Ice-Free Cooling to Storage Temperature. 无冰冷却至贮存温度期间残余热机械应力的结垢效应。

IF 2.6

Journal of Applied Mechanics Pub Date : 2020-10-01 Epub Date: 2020-07-08 DOI: 10.1115/1.4047420

Prem K Solanki, Yoed Rabin

{"title":"Scaling Effects on the Residual Thermomechanical Stress During Ice-Free Cooling to Storage Temperature.","authors":"Prem K Solanki, Yoed Rabin","doi":"10.1115/1.4047420","DOIUrl":"https://doi.org/10.1115/1.4047420","url":null,"abstract":"Cryopreservation via vitrification (glass formation) is a promising approach for long-term preservation of large-size tissues and organs. Unfortunately, thermomechanical stress, which is driven by the tendency of materials to change size with temperature, may lead to structural failure. This study focuses on analysis of thermomechanical stress in a realistic, pillow-like shape cryobag as it is cooled to cryogenic storage, subject to sufficiently high cooling rates to facilitate vitrification. Contrary to common perception, it is demonstrated in this study that the maximum stress in the specimen does not necessarily increase with increasing size of the specimen. In fact, the maximum stress is affected by the combination of two competing effects, associated with the extent of the temperature gradients within the specimen and its overall volume. On one hand, the increase in specimen size gives rise to more prominent temperature gradients, which can intensify the thermomechanical stress. On the other hand, the temperature distribution at the core of larger specimens is more uniform, which leads to a larger portion of the specimen transitioning from fluid to a glassy material almost instantaneously, which carries a moderating effect on the overall mechanical stress at the glassy state (i.e., lower residual stress). In conclusion, this study demonstrates the role of container shape optimization in reducing the thermomechanical stress during cooling.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"87 10","pages":"101003"},"PeriodicalIF":2.6,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208319/pdf/jam_87_10_101003.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39024627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Translation of a Coated Rigid Spherical Inclusion in an Elastic Matrix: Exact Solution, and Implications for Mechanobiology. 弹性矩阵中涂层刚性球形包涵体的翻译:精确解，及其对力学生物学的影响。

IF 2.6

Journal of Applied Mechanics Pub Date : 2019-05-01 Epub Date: 2019-03-05 DOI: 10.1115/1.4042575

Xin Chen, Moxiao Li, Shaobao Liu, Fusheng Liu, Guy M Genin, Feng Xu, Tian Jian Lu

{"title":"Translation of a Coated Rigid Spherical Inclusion in an Elastic Matrix: Exact Solution, and Implications for Mechanobiology.","authors":"Xin Chen, Moxiao Li, Shaobao Liu, Fusheng Liu, Guy M Genin, Feng Xu, Tian Jian Lu","doi":"10.1115/1.4042575","DOIUrl":"https://doi.org/10.1115/1.4042575","url":null,"abstract":"The displacement of relatively rigid beads within a relatively compliant, elastic matrix can be used to measure the mechanical properties of the matrix. For example, in mechanobiological studies, magnetic or reflective beads can be displaced with a known external force to estimate the matrix modulus. Although such beads are generally rigid compared to the matrix, the material surrounding the beads typically differs from the matrix in one or two ways. The first case, as is common in mechanobiological experimentation, is the situation in which the bead must be coated with materials such as protein ligands that enable adhesion to the matrix. These layers typically differ in stiffness relative to the matrix material. The second case, common for uncoated beads, is the situation in which the beads disrupt the structure of the hydrogel or polymer, leading to a region of enhanced or reduced stiffness in the neighborhood of the bead. To address both cases, we developed the first analytical solution of the problem of translation of a coated, rigid spherical inclusion displaced within an isotropic elastic matrix by a remotely applied force. The solution is applicable to cases of arbitrary coating stiffness and size of the coating. We conclude by discussing applications of the solution to mechanobiology.","PeriodicalId":508156,"journal":{"name":"Journal of Applied Mechanics","volume":"86 5","pages":"0510021-5100210"},"PeriodicalIF":2.6,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4042575","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37446598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6