[ { "id": "https://authors.library.caltech.edu/records/yp183-47g88", "eprint_id": 63072, "eprint_status": "archive", "datestamp": "2023-08-20 09:14:42", "lastmod": "2023-10-25 23:29:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rosakis-P", "name": { "family": "Rosakis", "given": "Phoebus" } }, { "id": "Notbohm-J", "name": { "family": "Notbohm", "given": "Jacob" } }, { "id": "Ravichandran-G", "name": { "family": "Ravichandran", "given": "Guruswami" }, "orcid": "0000-0002-2912-0001" } ] }, "title": "A model for compression-weakening materials and the elastic fields due to contractile cells", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 Elsevier Ltd. \n\nReceived 4 May 2015, Revised 7 August 2015, Accepted 25 August 2015, Available online 2 September 2015. \n\nThis work was motivated by experiments performed in collaboration with Dr. Ayelet Lesman and Professor David Tirrell under a grant from the National Science Foundation (Division of Materials Research No. 0520565) through the Center for the Science and Engineering of Materials at the California Institute of Technology. P.R. acknowledges the hospitality of the Graduate Aerospace Laboratories at the California Institute of Technology (GALCIT).\n\n
Submitted - 1412.2612v3.pdf
", "abstract": "We construct a homogeneous, nonlinear elastic constitutive law that models aspects of the mechanical behavior of inhomogeneous fibrin networks. Fibers in such networks buckle when in compression. We model this as a loss of stiffness in compression in the stress\u2013strain relations of the homogeneous constitutive model. Problems that model a contracting biological cell in a finite matrix are solved. It is found that matrix displacements and stresses induced by cell contraction decay slower (with distance from the cell) in a compression weakening material than linear elasticity would predict. This points toward a mechanism for long-range cell mechanosensing. In contrast, an expanding cell would induce displacements that decay faster than in a linear elastic matrix.", "date": "2015-12", "date_type": "published", "publication": "Journal of the Mechanics and Physics of Solids", "volume": "85", "publisher": "Elsevier", "pagerange": "16-32", "id_number": "CaltechAUTHORS:20151218-112112538", "issn": "0022-5096", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151218-112112538", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "0520565" } ] }, "local_group": { "items": [ { "id": "GALCIT" } ] }, "doi": "10.1016/j.jmps.2015.08.013", "primary_object": { "basename": "1412.2612v3.pdf", "url": "https://authors.library.caltech.edu/records/yp183-47g88/files/1412.2612v3.pdf" }, "resource_type": "article", "pub_year": "2015", "author_list": "Rosakis, Phoebus; Notbohm, Jacob; et el." }, { "id": "https://authors.library.caltech.edu/records/7hhd9-rr083", "eprint_id": 55288, "eprint_status": "archive", "datestamp": "2023-08-21 21:14:19", "lastmod": "2023-10-20 22:04:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hodowany-J", "name": { "family": "Hodowany", "given": "J." } }, { "id": "Ravichandran-G", "name": { "family": "Ravichandran", "given": "G." }, "orcid": "0000-0002-2912-0001" }, { "id": "Rosakis-A-J", "name": { "family": "Rosakis", "given": "A. J." }, "orcid": "0000-0003-0559-0794" }, { "id": "Rosakis-P", "name": { "family": "Rosakis", "given": "P." } } ] }, "title": "Partition of Plastic Work into Heat and Stored Energy in Metals", "ispublished": "pub", "full_text_status": "restricted", "keywords": "plastic work; heat; infrared detectors; dynamic; stored energy; cold work; high strain rates; Kolsky bar/SHPB", "note": "\u00a9 2000 Springer International Publishing AG. \n\nOriginal manuscript submitted: June 22, 1999. Final manuscript received: October 23, 1999. \n\nThe second and third authors gratefully acknowledge support from the Office of Naval Research (Grant N0014-95-1-0453) and the National Science Foundation (Grant CMS-9204026). The fourth author would like to thank J. K. Knowles and the Caltech Faculty for their hospitality during his visit to the California Institute of Technology, and the National Science Foundation (Grant MSS-9312858).", "abstract": "This study investigates heat generation in metals during plastic deformation. Experiments were designed to measure the partition of plastic work into heat and stored energy during dynamic deformations under adiabatic conditions. A servohydraulic load frame was used to measure mechanical properties at lower strain rates, 10^(\u22123) s^(\u22121) to 1 s^(\u22121). A Kolsky pressure bar was used to determine mechanical properties at strain rates between 10^3 s^(\u22121) and 10^4 s^(\u22121). For dynamic loading, in situ temperature changes were measured using a high-speed HgCdTe photoconductive detector. An aluminum 2024-T3 alloy and \u03b1-titanium were used to determine the dependence of the fraction of plastic work converted to heat on strain and strain rate. The flow stress and \u03b2 for 2024-T3 aluminum alloy were found to be a function of strain but not strain rate, whereas they were found to be strongly dependent on strain rate for \u03b1-titanium.", "date": "2000-06", "date_type": "published", "publication": "Experimental Mechanics", "volume": "40", "number": "2", "publisher": "Springer", "pagerange": "113-123", "id_number": "CaltechAUTHORS:20150226-165652488", "issn": "0014-4851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150226-165652488", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Office of Naval Research (ONR)", "grant_number": "N0014-95-1-0453" }, { "agency": "NSF", "grant_number": "CMS-9204026" }, { "agency": "NSF", "grant_number": "MSS-9312858" } ] }, "local_group": { "items": [ { "id": "GALCIT" } ] }, "doi": "10.1007/BF02325036", "resource_type": "article", "pub_year": "2000", "author_list": "Hodowany, J.; Ravichandran, G.; et el." }, { "id": "https://authors.library.caltech.edu/records/bzdz6-0yd40", "eprint_id": 55289, "eprint_status": "archive", "datestamp": "2023-08-21 20:57:32", "lastmod": "2023-10-20 22:04:26", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rosakis-P", "name": { "family": "Rosakis", "given": "P." } }, { "id": "Rosakis-A-J", "name": { "family": "Rosakis", "given": "A. J." }, "orcid": "0000-0003-0559-0794" }, { "id": "Ravichandran-G", "name": { "family": "Ravichandran", "given": "G." }, "orcid": "0000-0002-2912-0001" }, { "id": "Hodowany-J", "name": { "family": "Hodowany", "given": "J." } } ] }, "title": "A Thermodynamic Internal Variable Model for the Partition of Plastic Work into Heat and Stored Energy in Metals", "ispublished": "pub", "full_text_status": "restricted", "keywords": "thermomechanical processes; constitutive behavior; viscoplastic material; kolsky bar", "note": "\u00a9 2000 Published by Elsevier Science Ltd. \n\nReceived 10 June 1998; received in revised form 16 June 1999.\n\nThis work was initiated while P.R. was on leave at the California Institute of Technology; he would like to thank J. K. Knowles and the GALCIT Faculty for their hospitality, also the National Science Foundation for support through Grant MSS-9312858. G.R. and A.J.R. gratefully acknowledge support from the Office of Naval Research (Scientific Officer: Dr Y. D. S. Rajapakse) through Grant N0014-95-1-0453 and the National Science Foundation through Grant CMS-9204026.", "abstract": "The energy balance equation for elastoplastic solids includes heat source terms that govern the conversion of some of the plastic work into heat. The remainder contributes to the stored energy of cold work due to the creation of crystal defects. This paper is concerned with the fraction \u03b2 of the rate of plastic work converted into heating. We examine the status of the common assumption that \u03b2 is a constant with regard to the thermodynamic foundations of thermoplasticity and experiments. A general internal-variable theory is introduced and restricted to abide by the second law of thermodynamics. Experimentally motivated assumptions reduce this theory to a special model of classical thermoplasticity. The only part of the internal energy not determined from the isothermal response is the stored energy of cold work, a function only of the internal variables. We show that this function can be inferred from stress and temperature data from a single adiabatic straining experiment. Experimental data from dynamic Kolsky-bar tests at various strain rates yield a unique stored energy function. Its knowledge is crucial for the determination of the thermomechanical response in non-isothermal processes. Such a prediction agrees well with results from dynamic tests at different rates. In these experiments, \u03b2 is found to depend strongly on both strain and strain rate for various engineering materials. The model is successful in predicting this dependence. Requiring \u03b2 to be constant is thus an approximation of dubious validity.", "date": "2000-03", "date_type": "published", "publication": "Journal of the Mechanics and Physics of Solids", "volume": "48", "number": "3", "publisher": "Elsevier", "pagerange": "581-607", "id_number": "CaltechAUTHORS:20150226-170425585", "issn": "0022-5096", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150226-170425585", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "MSS-9312858" }, { "agency": "Office of Naval Research (ONR)", "grant_number": "N0014-95-1-0453" }, { "agency": "NSF", "grant_number": "CMS-9204026" } ] }, "local_group": { "items": [ { "id": "GALCIT" } ] }, "doi": "10.1016/S0022-5096(99)00048-4", "resource_type": "article", "pub_year": "2000", "author_list": "Rosakis, P.; Rosakis, A. J.; et el." }, { "id": "https://authors.library.caltech.edu/records/k1ecg-h5q92", "eprint_id": 50608, "eprint_status": "archive", "datestamp": "2023-08-22 13:28:51", "lastmod": "2023-10-17 23:58:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rosakis-P", "name": { "family": "Rosakis", "given": "Phoebus" } }, { "id": "Knowles-J-K", "name": { "family": "Knowles", "given": "James K." } } ] }, "title": "Continuum models for irregular phase boundary motion in shape-memory tensile bars", "ispublished": "pub", "full_text_status": "restricted", "keywords": "hysteresis; kinetic relation; shape-memory; stick-slip", "note": "\u00a9 1999 Elsevier, Paris.\n\nReceived 21 November 1997; revised and accepted 10 February 1998.\n\nThe authors have had the benefit of many helpful conversations with Rohan Abeyaratne. Financial support\nduring the course of this work from the U.S. National Science Foundation (P.R.) as well as the U.S. Office of\nNaval Research (J.K.K.) is also gratefully acknowledged.", "abstract": "We consider quasi-static displacement-controlled loading through one stress cycle of a shape-memory tensile bar modeled as a one-dimensional, two-phase elastic solid. Our objective is to explore the effect on the associated hysteresis loop of various qualitatively different types of kinetic relations, bearing in mind certain features of such loops that have been observed experimentally. We show that when the model involves a kinetic relation that is 'unstable' in a definite sense, 'stick-slip' motion of the interface between phases and serration of the accompanying stress-elongation curve are both predicted at slow elongation rates. We also show that a 'nonhomogeneous' kinetic relation intended to model the effect of micro-obstacles on interface motion also leads to irregular interface motion and a serrated stress-elongation curve, in this case at all elongation rates.", "date": "1999-01", "date_type": "published", "publication": "European Journal of Mechanics - A/Solids", "volume": "18", "number": "1", "publisher": "Elsevier", "pagerange": "1-16", "id_number": "CaltechAUTHORS:20141021-110039001", "issn": "0997-7538", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141021-110039001", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Office of Naval Research (ONR)" } ] }, "doi": "10.1016/S0997-7538(99)80001-1", "resource_type": "article", "pub_year": "1999", "author_list": "Rosakis, Phoebus and Knowles, James K." }, { "id": "https://authors.library.caltech.edu/records/3th1t-p7j59", "eprint_id": 50667, "eprint_status": "archive", "datestamp": "2023-09-15 04:52:24", "lastmod": "2023-10-23 21:10:53", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rosakis-P", "name": { "family": "Rosakis", "given": "Phoebus" } }, { "id": "Knowles-J-K", "name": { "family": "Knowles", "given": "James K." } } ] }, "title": "Unstable kinetic relations and the dynamics of solid-solid phase transitions", "ispublished": "pub", "full_text_status": "restricted", "keywords": "acoustics; phase transformation; shock waves; stress waves; stability and bifurcation", "note": "\u00a9 1997 Elsevier Science Ltd.\n\nReceived 23 December 1996.\n\nThis work was supported in part by the U.S. National Science Foundation (PR) and the\nU.S. Office of Naval Research (JKK). The authors are grateful for helpful discussions with\nRohan Abeyaratne, Costas Papadimitriou and Lev Truskinovsky.", "abstract": "In recent continuum-mechanical models of phase transitions in solids, the kinetic relation for a transition is usually assumed to be such that the driving force acting on a phase boundary is a monotonically increasing function of phase boundary velocity. The present paper explores the implications of relinquishing this assumption in the dynamics of one-dimensional elastic bars undergoing stress-induced transitions. Among other results, it is found that, for a class of non-monotonic kinetic relations, models of the kind discussed here permit stick-slip motions of a phase boundary, as observed in certain experiments.", "date": "1997-12", "date_type": "published", "publication": "Journal of the Mechanics and Physics of Solids", "volume": "45", "number": "11-12", "publisher": "Elsevier", "pagerange": "2055-2081", "id_number": "CaltechAUTHORS:20141022-084738427", "issn": "0022-5096", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141022-084738427", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Office of Naval Research (ONR)" } ] }, "doi": "10.1016/S0022-5096(97)00026-4", "resource_type": "article", "pub_year": "1997", "author_list": "Rosakis, Phoebus and Knowles, James K." } ]