Academic literature on the topic 'Small deformation theory'
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Journal articles on the topic "Small deformation theory"
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Das, Debasish, and David Saintillan. "A nonlinear small-deformation theory for transient droplet electrohydrodynamics." Journal of Fluid Mechanics 810 (November 28, 2016): 225–53. http://dx.doi.org/10.1017/jfm.2016.704.
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The deformation of a viscous liquid droplet suspended in another liquid and subject to an applied electric field is a classic multiphase flow problem best described by the Melcher–Taylor leaky dielectric model. The main assumption of the model is that any net charge in the system is concentrated on the interface between the two liquids as a result of the jump in Ohmic currents from the bulk. Upon application of the field, the drop can either attain a steady prolate or oblate shape with toroidal circulating flows both inside and outside arising from tangential stresses on the interface due to action of the field on the surface charge distribution. Since the pioneering work of Taylor (Proc. R. Soc. Lond. A, vol. 291, 1966, pp. 159–166), there have been numerous computational and theoretical studies to predict the deformations measured in experiments. Most existing theoretical models, however, have either neglected transient charge relaxation or nonlinear charge convection by the interfacial flow. In this work, we develop a novel small-deformation theory accurate to second order in electric capillary number $O(Ca_{E}^{2})$ for the complete Melcher–Taylor model that includes transient charge relaxation, charge convection by the flow, as well as transient shape deformation. The main result of the paper is the derivation of coupled evolution equations for the induced electric multipoles and for the shape functions describing the deformations on the basis of spherical harmonics. Our results, which are consistent with previous models in the appropriate limits, show excellent agreement with fully nonlinear numerical simulations based on an axisymmetric boundary element formulation and with existing experimental data in the small-deformation regime.
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Schmidt, R., and J. N. Reddy. "A Refined Small Strain and Moderate Rotation Theory of Elastic Anisotropic Shells." Journal of Applied Mechanics 55, no. 3 (1988): 611–17. http://dx.doi.org/10.1115/1.3125837.
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A general refined shell theory that accounts for the transverse deformation, small strains, and moderate rotations is presented. The theory can be reduced to various existing shell theories including: the classical (i.e., linear Kirchhoff-Love) shell theory, the Donnell-Mushtari-Vlasov shell theory, the Leonard-Koiter-Sanders moderate rotations shell theory, the von Ka´rma´n type shear-deformation shell theory and the moderate-rotation shear-deformation plate theory developed by Reddy. The present theory is developed from an assumed displacement field, nonlinear strain-displacement equations that contain small strain and moderate rotation terms, and the principle of virtual displacements. The governing equations exhibit strong coupling between the membrane and bending deformations, which should alter the bending, stability, and post-buckling behavior of certain shell structures predicted using the presently available theories.
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WETZEL, ERIC D., and CHARLES L. TUCKER. "Droplet deformation in dispersions with unequal viscosities and zero interfacial tension." Journal of Fluid Mechanics 426 (January 10, 2001): 199–228. http://dx.doi.org/10.1017/s0022112000002275.
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An analytical model is presented for the deformation of an ellipsoidal Newtonian droplet, suspended in another Newtonian fluid with different viscosity and zero interfacial tension. The theory is exact for any linear velocity field, and is not limited to small deformations. It encompasses some well-known special cases, such as Jeffery's equation for solid axisymmetric particles and Taylor's small-deformation theory for droplets. Example calculations exhibit droplet stretching, reorientation, and tumbling, and provide a reasonable match to available experimental data on transient and steady droplet shapes. The corresponding rheological theory for dilute dispersions is also derived, in a form that explicitly includes the effects of microstructure on dispersion rheology.
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Klochkov, Yuriy V., Anatoliy P. Nikolaev, Olga V. Vakhnina, and Mikhail Yu Klochkov. "Variants of determining correlations of deformation theory of plasticity in the calculation of shell of rotation on the basis of finite element method." Structural Mechanics of Engineering Constructions and Buildings 15, no. 4 (2019): 315–22. http://dx.doi.org/10.22363/1815-5235-2019-15-4-315-322.
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Relevance. The problems of decline of resource-demanding of objects of building and engineer dictate the necessity of consideration of processes of deformation of constructions at the resiliently-plastic state. The widely in-use theory of account of practical properties of material is a deformation theory of plasticity. The aim of the research is development of variants of receipt of determining correlations on the step of ladening at deformation of material outside a resiliency. Methods. Algorithms over of receipt of determining correlations of theory of small resiliently-plastic deformations are brought on the step of ladening in two variants. In the first they turn out differentiation of expressions of tensions as functions of deformations on the basis of deformation theory of plasticity; in the second determining correlations turn out on the basis of hypothesis about the proportion of components of deviators increases of tensions to components of deviators increases of deformations. Results. On the test example of calculation of the jammed cylindrical shell realization of the got determining correlations is presented.
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Eriksen, Eivind. "Computing Noncommutative Deformations of Presheaves and Sheaves of Modules." Canadian Journal of Mathematics 62, no. 3 (2010): 520–42. http://dx.doi.org/10.4153/cjm-2010-015-6.
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AbstractWe describe a noncommutative deformation theory for presheaves and sheaves of modules that generalizes the commutative deformation theory of these global algebraic structures and the noncommutative deformation theory of modules over algebras due to Laudal.In the first part of the paper, we describe a noncommutative deformation functor for presheaves of modules on a small category and an obstruction theory for this functor in terms of global Hochschild cohomology. An important feature of this obstruction theory is that it can be computed in concrete terms in many interesting cases.In the last part of the paper, we describe a noncommutative deformation functor for quasi-coherent sheaves of modules on a ringed space (X,𝒜). We show that for any good A-affine open cover U of X, the forgetful functor QCoh𝒜 → PreSh(U,𝒜) induces an isomorphism of noncommutative deformation functors.Applications. We consider noncommutative deformations of quasi-coherent 𝒜-modules on X when (X,𝒜) = (X,𝒪X) is a scheme or (X,𝒜) = (X,𝒟) is a D-scheme in the sense of Beilinson and Bernstein. In these cases, we may use any open affine cover of X closed under finite intersections to compute noncommutative deformations in concrete terms using presheaf methods. We compute the noncommutative deformations of the left 𝒟X-module 𝒟X when X is an elliptic curve as an example.
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Fashanu, T. A., A. T. Adebusoye, A. A. Oyediran, and O. O. Adewumi. "Dynamic analysis of the large strain deformation of flexible pipes conveying two-phase fluids. Part II: nonlinear vibration analysis." Nigerian Journal of Technology 42, no. 1 (2023): 130–35. http://dx.doi.org/10.4314/njt.v42i1.16.
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This work presents the nonlinear analysis of the dynamics of large strain deformation of subsea flowlines and jumpers conveying two-phase fluid. Precisely, flexible pipes operating in the stated condition undergo large strain deformations. Thus, the known nonlinear deterministic model of the system is solved using method of discretized perturbation. Precisely, this study obtained the nonlinear natural frequency of simply supported flexible pipes modelled using the large strain deformation theory. Results show that both hardening and softening nonlinear behaviors are indicated for pipe undergoing large strain deformation compared with deformations modelled with small strain theory. Thus, operational insights and parameters for sustainable management of large strain deformed subsea flow lines and jumpers conveying two phase flow are made available.
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Hakimi Siboni, Morteza, and Pedro Ponte Castañeda. "Dielectric elastomer composites: small-deformation theory and applications." Philosophical Magazine 93, no. 21 (2013): 2769–801. http://dx.doi.org/10.1080/14786435.2013.788258.
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Dunstan, D. J., and A. J. Bushby. "Theory of deformation in small volumes of material." Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 460, no. 2050 (2004): 2781–96. http://dx.doi.org/10.1098/rspa.2004.1306.
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Plavšić, M. B., Iva Pajić-Lijaković, and N. L. Lazić. "Scaling of Network Segment Dimensions in Hyperelastic Composites." Materials Science Forum 494 (September 2005): 463–68. http://dx.doi.org/10.4028/www.scientific.net/msf.494.463.
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The change in elastomer tensile moduli, as formulated in the Gaussian statistical theory of rubber elasticity, with deformation, is considered both experimentally and theoretically. Gum elastomers of different structures and corresponding materials filled with carbon black, as reinforcing filler, are investigated experimentally. For all materials considered, the same scaling pattern with negative and low slope for small deformations, and positive and higher slope for large deformations is obtained, indicating two distinct mechanisms of elastic response. Most pronounced is the similarity of small deformation responses for filled materials. Considering the modulus as an elastic energy density gradient dependent on structure changes with deformation, and interpreting the changes for small deformations in terms of conformational energy change, the fractal dimension of a new type is formulated. It describes the decrease in elastomer network connectivity with deformations, which is discussed in terms of conformon dynamics. Possibilities of application of Faynman's path integral method and statistical method of random walk to the lattice are considered for the conformon, as well.
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Wang, Zhi-bin, Jin-feng Zou, and Hai Yang. "A new approach for the fracture grouting pressure in soil mass." Advances in Mechanical Engineering 10, no. 7 (2018): 168781401878643. http://dx.doi.org/10.1177/1687814018786435.
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This study focuses on analytical solutions of the fracture grouting pressure. Based on the cavity expansion and fracture grouting mechanism, the small deformation in the elastic zone, large deformation in the plastic zone, and non-associated flow rules are assumed. The solutions of the fracture grouting pressure based on the Unified Strength failure criterion, spatial mobilized plane criterion, Mohr–Coulomb failure criterion, and modified Cambridge model (MMC) are proposed for the large-deformation and small-deformation assumptions, respectively. A parameter analysis was conducted to analyze the differences between large-deformation and small-deformation theories. A comparison of the local test data with theoretical results reveals that the Cambridge model is more suitable for weakly consolidated soil and that the Mohr–Coulomb theory is suitable for over-consolidated soil. For all yield criteria in the study, the analysis indicates that the large-deformation theory has more reliable results than the small-deformation theory. The results in this study can direct the design and operation of fracture grouting.
Dissertations / Theses on the topic "Small deformation theory"
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Jakel, Roland. "Das neue Kontaktmodell mit endlicher Reibung in Creo Simulate 3.0 : Theorie und Anwendung ; Vergleich mit dem reibungsfreien und unendlich reibungsbehafteten Kontaktmodell." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-206817.
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Der Vortrag beschreibt die zugrunde liegende Theorie und die Softwarefunktionalität des in PTC Creo Simulate 3.0 eingeführten Kontaktmodells mit endlicher Reibung und vergleicht dieses mit den bis Creo Simulate 2.0 exklusiv verwendeten Kontaktmodellen (ideal reibungsfrei und unendlich reibungsbehaftet). An zwei Modellbeispielen (ein von zwei Bremsbacken geklemmtes Bremsschwert und ein verschraubtes Schwungrad) wird versucht, die Funktionsweise des neuen Modells zu demonstrieren. Wegen aktueller Qualitätsprobleme der Software wird die Brauchbarkeit der Kontaktmodelle für den Anwender bewertet (Stand Creo 3.0 M080 / Creo 2.0 M200) und umfangreiches Feedback an den Softwarehersteller PTC gegeben<br>The presentation describes the underlying theory and software functionality of the finite friction contact model introduced with PTC Creo Simulate 3.0. It is being compared with the friction-free and infinite friction contact model used exclusively until Creo Simulate 2.0. It is being tried to demonstrate the mode of operation of the new model with help of two examples: A brake sword clamped by two brake pads and a bolted flywheel. Because of actual software quality problems, the usability of the contact model for the user is being rated (status Creo 3.0 M080 / Creo 2.0 M200). Furthermore, comprehensive feedback is given to the software developer PTC
Books on the topic "Small deformation theory"
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Reiss, Edward L. Theory for the Small Deformations of Cylindrical Shells: Part I- Rotationally Symmetric Deformations. Creative Media Partners, LLC, 2018.
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Anand, Lallit, and Sanjay Govindjee. Continuum Mechanics of Solids. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198864721.001.0001.
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Continuum mechanics of Solids presents a unified treatment of the major concepts in Solid Mechanics for beginning graduate students in the many branches of engineering. The fundamental topics of kinematics in finite and infinitesimal deformation, mechanical and thermodynamic balances plus entropy imbalance in the small strain setting are covered as they apply to all solids. The major material models of Elasticity, Viscoelasticity, and Plasticity are detailed and models for Fracture and Fatigue are discussed. In addition to these topics in Solid Mechanics, because of the growing need for engineering students to have a knowledge of the coupled multi-physics response of materials in modern technologies related to the environment and energy, the book also includes chapters on Thermoelasticity, Chemoelasticity, Poroelasticity, and Piezoelectricity. A preview to the theory of finite elasticity and elastomeric materials is also given. Throughout, example computations are presented to highlight how the developed theories may be applied.
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Abbes, Ahmed, and Michel Gros. Representations of the fundamental group and the torsor of deformations. Local study. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691170282.003.0002.
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This chapter focuses on representations of the fundamental group and the torsor of deformations. It considers the case of an affine scheme of a particular type, qualified also as small by Faltings. It introduces the notion of Dolbeault generalized representation and the companion notion of solvable Higgs module, and then constructs a natural equivalence between these two categories. It proves that this approach generalizes simultaneously Faltings' construction for small generalized representations and Hyodo's theory of p-adic variations of Hodge–Tate structures. The discussion covers the relevant notation and conventions, results on continuous cohomology of profinite groups, objects with group actions, logarithmic geometry lexicon, Faltings' almost purity theorem, Faltings extension, Galois cohomology, Fontaine p-adic infinitesimal thickenings, Higgs–Tate torsors and algebras, Dolbeault representations, and small representations. The chapter also describes the descent of small representations and applications and concludes with an analysis of Hodge–Tate representations.
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Abbes, Ahmed, and Michel Gros. Representations of the fundamental group and the torsor of deformations. An overview. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691170282.003.0001.
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This chapter provides an overview of a new approach to the p-adic Simpson correspondence, focusing on representations of the fundamental group and the torsor of deformations. The discussion covers the notation and conventions, small generalized representations, the torsor of deformations, Faltings ringed topos, and Dolbeault modules. The chapter begins with a short aside on small generalized representations in the affine case, which will be used as intermediary for the study of Dolbeault representations. It then introduces the notion of generalized Dolbeault representation for a small affine scheme and the companion notion of solvable Higgs module, and constructs a natural equivalence between these two categories. It establishes links between these notions and Faltings smallness conditions and relates this to Hyodo's theory. It also describes the Higgs–Tate algebras and concludes with an analysis of the logical links for a Higgs bundle, between smallness and solvability.
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Hrushovski, Ehud, and François Loeser. The main theorem. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691161686.003.0011.
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This chapter introduces the main theorem, which states: Let V be a quasi-projective variety over a valued field F and let X be a definable subset of V x Γsuperscript Script Small l subscript infinity over some base set V ⊂ VF ∪ Γ, with F = VF(A). Then there exists an A-definable deformation retraction h : I × unit vector X → unit vector X with image an iso-definable subset definably homeomorphic to a definable subset of Γsuperscript w subscript Infinity, for some finite A-definable set w. The chapter presents several preliminary reductions to essentially reduce to a curve fibration. It then constructs a relative curve homotopy and a liftable base homotopy, along with a purely combinatorial homotopy in the Γ-world. It also constructs the homotopy retraction by concatenating the previous three homotopies together with an inflation homotopy. Finally, it describes a uniform version of the main theorem with respect to parameters.
Book chapters on the topic "Small deformation theory"
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Yang, Jiashi. "Linear Theory for Small Deformation." In Advances in Mechanics and Mathematics. Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-86118-5_5.
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Li, Jianbin, Junguang Huang, Huawei Tong, and Shankai Zhang. "Study on Surface Deformation Model Induced by Shield Tunneling Based on Random Field Theory." In Lecture Notes in Civil Engineering. Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1260-3_40.
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AbstractBased on the shield tunnel engineering in weathered granite stratum in Xiamen, Stochastic calculations, by combining the random field theory and the finite difference analysis together with Monte Carlo simulation, are used to carry out the change law of the characteristics of surface deformation curve and surface deformation model. Results show that with the increase of the vertical scales of fluctuation, the decrease of the transverse scales of fluctuation or the increase of the coefficient of variation, the low peak distribution characteristics of the location of the maximum surface settlement induced by shield tunneling become more obvious, and the randomness and chaos of the shape of surface deformation curve gradually increase. The diversity of surface deformation model is affected by parameter correlation and randomness. Under the condition of small transverse scales of fluctuation and large vertical scales of fluctuation, the sensitivity of coefficient of variation to surface deformation mode is limited.
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Pipkin, A. C. "Large Deformations with Small Strains." In Lectures on Viscoelasticity Theory. Springer New York, 1986. http://dx.doi.org/10.1007/978-1-4612-1078-8_8.
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Johnson, Claes, and Peter Hansbo. "Adaptive Finite Element Methods for Small Strain Elasto-Plasticity." In Finite Inelastic Deformations — Theory and Applications. Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84833-9_25.
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Green, A. E., R. T. Shield, and R. S. Rivlin. "General theory of small elastic deformations superposed on finite elastic deformations." In Collected Papers of R.S. Rivlin. Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-2416-7_40.
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Steigmann, David J. "Small-deformation theory." In A Course on Plasticity Theory. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780192883155.003.0008.
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Abstract The small-deformation theory of elastic-plastic response, due to Prandtl and Reuss, is the basis of most analytical treatments of elastic-plastic behavior. This model is examined from a modern perspective. The shifter concept is combined with the convected coordinate formalism to cast the theory in a manner that ensures its invariance under a change of frame, in contrast to conventional expositions of the small-deformation theories of elasticity and elasto-plastic response
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Anand, Lallit, Ken Kamrin, and Sanjay Govindjee. "Three-dimensional small deformation theory of rate-independent plasticity." In Introduction to Mechanics of Solid Materials. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192866073.003.0013.
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Abstract This chapter discusses the small deformation three-dimensional Mises–Hill theory of rate-independent plasticity with isotropic hardening. The additive decomposition of the strain tensor into elastic and plastic parts is introduced, together with the assumption of plastic incompressibility. The Mises yield condition and the concept of isotropic strain-hardening are introduced, as is a plastic flow rule—together with attendant loading/unloading conditions—to formulate a complete macroscopic theory for three-dimensional rate-independent elastic-plastic deformation of metallic solids. The rigid-plastic limit of this theory is discussed, along with an extension to large deformations, valid for proportional loading paths.
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"Small Deformation of an Initially Loaded Body." In Nonlinear Theory of Elasticity. Elsevier, 1990. http://dx.doi.org/10.1016/b978-0-444-87439-9.50013-9.
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Krempl, Erhard. "A Small-Strain Viscoplasticity Theory Based on Overstress." In Unified Constitutive Laws of Plastic Deformation. Elsevier, 1996. http://dx.doi.org/10.1016/b978-012425970-6/50007-2.
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Hill, R. "The solution of plastic-elastic problems. I." In The Mathematical Theory Of Plasticity. Oxford University PressOxford, 1998. http://dx.doi.org/10.1093/oso/9780198503675.003.0004.
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Abstract The complete solution of a general problem in plasticity involves a calculation of the stress and the deformation in both the elastic and plastic regions. In the former the stress is directly connected with the total strain by means of the elastic equations. In the latter there is, as we have seen, no such unique correspondence, and the stress-strain differential relations have to be integrated by following the history of the deformation from the initiation of plasticity at some point of the body. A process of plastic deformation has to be considered mathematically as a succession of small. increments of strain, even where the overall distortion is so small that the change in external surfaces can be neglected. When the strains are large the determination of the changing shape of free plastic surfaces necessitates, in itself, the following of the deformation from moment to moment.
Conference papers on the topic "Small deformation theory"
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Tan, Qiao, Liwu Liu, Yanju Liu, Jinsong Leng, Xiangqiao Yan, and Haifang Wang. "A constitutive theory for shape memory polymers: coupling of small and large deformation." In SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, edited by Nakhiah C. Goulbourne and Hani E. Naguib. SPIE, 2013. http://dx.doi.org/10.1117/12.2009671.
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Goyal, Sachin. "Modeling Thermal Fluctuations of Bio-Filaments With Elastic Rod Theory." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13457.
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Bio-filaments at sub-micron scales such as DNA perform their biological functions via well-regulated structural deformations that involve large twisting and bending. The strain energies associated with these deformations are of the order of the thermal kinetic energies of surrounding solvent molecules. Therefore, the bio-filaments at such small length scales also exhibit large fluctuations in their shape due to the random collisions of the solvent molecules with them. These thermal fluctuations may, on one hand, help the bio-filaments explore functionally desirable configuration space, while, on the other hand, hinder the regulation of their deformations by motor proteins. Nevertheless, it seems indispensable to model the thermal fluctuations to accurately study the dynamics of deformation of bio-filaments. This paper presents the first elastic rod formulation that incorporates the thermal fluctuations by modeling the impacts of solvent molecules as distributed stochastic force. For quasi-static fluctuations, this formulation leverages the simplicity of a rod formulation noted by Anker et al. [1] that allows solving it as an initial value problem (IVP) in single iteration, and yet capturing arbitrarily large (nonlinear) deformations with rigorous description of constitutive laws.
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Jiang, Fang, and Wenbin Yu. "Prediction of Sectional Collapse of Thin-Walled Structure Under Pure Bending by Nonlinear Composite Beam Theory." In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-96539.
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Abstract Brazier [1] found that when one dimension of the beam cross-section was relatively smaller than the others, large in-plane displacements over the cross-section might occur, even though the strains could remain very small. Under this circumstance, the so-called Brazier effect refers to the cross-sectional ovalization, which leads to nonlinear bending buckling and collapses. This paper extends the Variational Asymptotic Beam Sectional Analysis (VABS) theory to consider finite cross-sectional deformations. The three-dimensional (3D) continuum is reduced to a one-dimensional (1D) beam analysis and a two-dimensional (2D) cross-sectional analysis featuring both geometric and material nonlinearities without unnecessary kinematic assumptions. The present theory is implemented using the finite element method (FEM) in the VABS code, a general-purpose beam cross-sectional analysis tool. An iterative method is applied to solve the finite warping field for the classical-type model using the Euler-Bernoulli beam theory. The deformation gradient tensor is directly used to deal with finite deformation, various strain definitions, and several types of material laws regarding nonlinear elasticity and progressive damage. Numerical examples demonstrate the capabilities of VABS to predict the sectional collapse of thin-walled structures under pure bending.
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Radwan, Ahmed M., Ibrahim A. El-Araby, Ehab R. Tolba, and Mohmaed M. El-Gendy. "Small Deformation Finite Element Analysis of Spudcan Penetration in Multi-Layered Soil." In Offshore Technology Conference. OTC, 2023. http://dx.doi.org/10.4043/32523-ms.
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Abstract Using the press-replace technique, a recently developed finite element method depending on the criteria of the small deformation analysis SDA, to investigate the soil-foundation interaction of the Jack-Up rig with Spudcan during its proceeding to achieve stability installation in Multi-Layered soil. The analysis has been implemented and compared with previously published cases, which has been done experimentally and by using large deformation finite element analysis. The Press-Replace technique PRT is mainly has been developed able to capture the Spudcan proceeding through the multi-layered soil specifically in cases of penetrating through soft soils by simulating the possible squeezing accompanied by the back-flow phenomenon, which happens for the soft soil during the installation. The considered analysis criteria have been explicated. The results provided an effective expectation of the soil-structure interaction validated by the previous experimental and numerical results. Depending on the detailed analysis steps provided, engineers and researchers can use it to make the needed analysis for similar case studies. The small deformation analysis SDA has been operated on six cases of multi-layered soils and compared to the previous experimental and numerical results. The variety of investigated cases was depending on the type of upper layered, either it was a soft to moderate clay layer or a sand layer. The two main criteria have been considered in the current analysis, which is the backflow of clay and the back-fill of sand. As the analysis theory depends mainly on the geometry update, the simulation steps of these two criteria have been provided in detail. That control has been applied, by observing the soil movement behavior of the previous experimental outcomes. Four cases with upper clay soil and other two cases with upper sand layers have been investigated and compared to previous experimental and numerical results. By controlling these two states of the upper soil layer, it can be obtained the different simulation steps in the analysis in the condition of the existing upper layer is sand or clay. The analysis provided shows a good comparison of stability depth to the previous results. Furthermore, it gives a very close evaluation behavior to the previous experimental results. This approach numerical method provides a tool for the engineers to use the Press-Replace technique PRT, which is a smooth and fast numerical technique compared to the other numerical methods, to investigate and obtain the Spudcan penetration through similar cases of multi-layered soil.
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Takahashi, Yoshitaka, and Nobuyuki Shimizu. "Study on Elastic Forces of the Absolute Nodal Coordinate Formulation for Deformable Beams." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/vib-8203.
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Abstract There are three basic finite element formulations which are used in the dynamics of flexible beams. These are the floating frame of reference approach, the finite segment method and the large rotation vector approach. Recently, the absolute nodal coordinate formulation was proposed by A.A.Shabana et al. In this procedure, there is no need to transform the element matrices since the equations of motion are defined in terms of absolute nodal coordinates. The mass matrix becomes constant, whereas the stiffness matrix becomes nonlinear function of time, even in case of linear elastic problems. One possible method to avoid such cumbersome of the absolute nodal coordinate formulation in calculating clastic forces is to assume the infinitesimal deformation theory against beams undergoing large rotation. In this paper, a new formulation to calculate the elastic forces and add the rotary inertia effects in the expression of the inertia forces. This formulation is based on the assumption that the deformations within each element remain very small. The expression of the resulting clastic force is simple, and the need for performing coordinate transformation is avoided. As the method assumes that the deformation of the beam from a selected beam axis is very small, a large number of finite elements is required for large deformation problems. However, the formulation has been found to be efficient for large rotation and medium deformation problems. Numerical examples are demonstrated for this formulation by using planar flexible pendulum problems.
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Bae, Dae Sung. "Development of a New Multi-Flexible Body Dynamics (MFBD) Platform: A Relative Nodal Displacement Method for Finite Element Analysis." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84723.
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Recently the analysis of multi flexible body dynamics has been a hot issue in the area of the computational dynamics research. There have been two main streams of research. One is the extension of conventional FEA theory for the multi flexible body systems, using either the total Lagrangian or updated Lagrangian method. The other is the extension of the multi body dynamics theory. The latter is the topic of this research. One essential requirement of a shape function in FEA theory is ability to represent the rigid body motion. This research proposes to use the moving reference frame to represent the rigid body motion. Therefore, the shape function does not need to have ability to represent the rigid body motion. The moving reference frame covers the rigid body. Since the nodal displacements are measured relative to its adjacent moving nodal reference frame, they are still small for a truss structure undergoing large deformations if the element sizes are small. As a consequence, many element formulations developed under small deformation assumptions are still valid for structures undergoing large deformations, which significantly simplifies the equations of equilibrium. Several numerical examples are analyzed to demonstrate the efficiency and validity of the proposed method.
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Massoudi, Mehrdad, Jeongho Kim, Samuel J. Hund, and James F. Antaki. "Application of the Theory of Interacting Continua to Blood Flow." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53260.
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Micro-scale investigations of the flow and deformation of blood and its formed elements have been studied for many years. Early in vitro investigations in the rotational viscometers or small glass tubes revealed important rheological properties such as the reduced blood apparent viscosity, Fahraeus effect and Fahraeus-Lindqvist effect [1], exhibiting the nonhomogeneous property of blood in microcirculation. We have applied Mixture Theory, also known as Theory of Interacting Continua, to study and model this property of blood [2, 3]. This approach holds great promise for predicting the trafficking of RBCs in micro-scale flows (such as the depletion layer near the wall), andother unique hemorheological phenomena relevant to blood trauma. The blood is assumed to be composed of an RBC component modeled as a nonlinear fluid, suspended in plasma, modeled as a linearly viscous fluid.
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Murai, Motohiko, Ken Haneda, Jun Yamanoi, and Yuta Abe. "Experimental Study on a Motion of “Underwater Platform” Including Hydro-Elastic Deformation in Waves." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41722.
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A new type of floater for floating offshore wind turbine (FOWT) was proposed. The floater, named an “underwater platform”, aims at high economic efficiency of energy generation of floating wind farm. The underwater platform is a large scale submerged structure which has small water plane area and can support several wind turbines. It is expected that the platform has small motion characteristics in waves because of its small water plane area, and it contributes for FOWT to generate energy safety. In this study, the feasibility and usefulness study about the platform was carried out through experiments and numerical simulations. The first experiment was conducted with partial rigid model of the platform to verify the feasibility. From the experiment, it was confirmed that the model has small motion characteristics in waves. The experimental results were compared with numerical simulations of potential theory and they were well matched. Besides, the coupling analysis with aero-hydro dynamics was also carried out and it was confirmed that the stability of the platform was enough in steady wind condition. The second experiment was conducted with elastic body model to study the elastic deformation of the platform in waves. From the experiment, it was confirmed that the deformation is small when the draft was 250mm (50m in the actual model).
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Deng, Yang-chun, and Gang Chen. "Expressions of Load and Structural Deformation Relationship for Cylindrical and Spherical Vessels Under Internal Pressure." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25648.
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Large deformation analysis for pressure vessel is much more complex than small deformation analysis, therefore, right now, there is no common recognized direct solution for load bearing capacity of pressure vessel yet, and this restrict the application of large deformation analysis in pressure vessel design. This paper based on elastic-plastic theory and considered material strain hardening and structural deformation effects, expressions of load and structural deformation relationship were the first time being derived for cylindrical and spherical vessels under internal pressure. And its practical value is equivalent to principal stress equations of thin-walled cylindrical and spherical vessels with considering non-linear structural deformation effect. Based on the study above and by introducing true stress-strain relationship of materials, analytical solutions of plastic instability pressure for thin-walled cylindrical and spherical vessels were derived.
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Zhu, Xian-Kui, and Brian N. Leis. "Bending Modified J-Q Theory and Its Application to Fracture Constraint Analysis." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26270.
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The J-Q theory [1,2] can characterize the crack-tip fields and quantify fracture constraints for various geometric and loading configurations in elastic-plastic materials, but it fails to do so for bending-dominant geometries at large-scale yielding (LSY). This issue significantly restricts its applications to fracture constraint analysis. A modification of the J-Q theory is thus proposed in this paper as a three-term solution with an additional term to address the global bending stress to offset this restriction. The nonlinear global bending stress is linearly approximated in the region of interest at LSY. To verify the bending-modified J-Q solution, detailed elastic-plastic finite element analysis (FEA) is carried out under plane strain conditions for three conventional bending specimens, i.e., single edge notched bend (SENB), single edge notched tension (SENT) and compact tension (CT) specimens for X80 pipeline steel. Deformation considered varies from small-scale yielding (SSY) to LSY. The results show that the bending modified J-Q solution can well match FEA results of crack-tip stress fields for the bending specimens at all deformation levels from SSY to LSY, and the modified parameter Q is a load- and distance-independent constraint parameter at LSY. Thus, the modified parameter Q can be effectively used to quantify the crack-tip constraint for bending geometries. Its application to fracture constraint analysis is demonstrated by ranking crack-tip constraint levels for fracture specimens and by determining constraint corrected J-R curves for the X80 pipeline steel.
Reports on the topic "Small deformation theory"
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Snyder, Victor A., Dani Or, Amos Hadas, and S. Assouline. Characterization of Post-Tillage Soil Fragmentation and Rejoining Affecting Soil Pore Space Evolution and Transport Properties. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7580670.bard.
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Tillage modifies soil structure, altering conditions for plant growth and transport processes through the soil. However, the resulting loose structure is unstable and susceptible to collapse due to aggregate fragmentation during wetting and drying cycles, and coalescense of moist aggregates by internal capillary forces and external compactive stresses. Presently, limited understanding of these complex processes often leads to consideration of the soil plow layer as a static porous medium. With the purpose of filling some of this knowledge gap, the objectives of this Project were to: 1) Identify and quantify the major factors causing breakdown of primary soil fragments produced by tillage into smaller secondary fragments; 2) Identify and quantify the. physical processes involved in the coalescence of primary and secondary fragments and surfaces of weakness; 3) Measure temporal changes in pore-size distributions and hydraulic properties of reconstructed aggregate beds as a function of specified initial conditions and wetting/drying events; and 4) Construct a process-based model of post-tillage changes in soil structural and hydraulic properties of the plow layer and validate it against field experiments. A dynamic theory of capillary-driven plastic deformation of adjoining aggregates was developed, where instantaneous rate of change in geometry of aggregates and inter-aggregate pores was related to current geometry of the solid-gas-liquid system and measured soil rheological functions. The theory and supporting data showed that consolidation of aggregate beds is largely an event-driven process, restricted to a fairly narrow range of soil water contents where capillary suction is great enough to generate coalescence but where soil mechanical strength is still low enough to allow plastic deforn1ation of aggregates. The theory was also used to explain effects of transient external loading on compaction of aggregate beds. A stochastic forInalism was developed for modeling soil pore space evolution, based on the Fokker Planck equation (FPE). Analytical solutions for the FPE were developed, with parameters which can be measured empirically or related to the mechanistic aggregate deformation model. Pre-existing results from field experiments were used to illustrate how the FPE formalism can be applied to field data. Fragmentation of soil clods after tillage was observed to be an event-driven (as opposed to continuous) process that occurred only during wetting, and only as clods approached the saturation point. The major mechanism of fragmentation of large aggregates seemed to be differential soil swelling behind the wetting front. Aggregate "explosion" due to air entrapment seemed limited to small aggregates wetted simultaneously over their entire surface. Breakdown of large aggregates from 11 clay soils during successive wetting and drying cycles produced fragment size distributions which differed primarily by a scale factor l (essentially equivalent to the Van Bavel mean weight diameter), so that evolution of fragment size distributions could be modeled in terms of changes in l. For a given number of wetting and drying cycles, l decreased systematically with increasing plasticity index. When air-dry soil clods were slightly weakened by a single wetting event, and then allowed to "age" for six weeks at constant high water content, drop-shatter resistance in aged relative to non-aged clods was found to increase in proportion to plasticity index. This seemed consistent with the rheological model, which predicts faster plastic coalescence around small voids and sharp cracks (with resulting soil strengthening) in soils with low resistance to plastic yield and flow. A new theory of crack growth in "idealized" elastoplastic materials was formulated, with potential application to soil fracture phenomena. The theory was preliminarily (and successfully) tested using carbon steel, a ductile material which closely approximates ideal elastoplastic behavior, and for which the necessary fracture data existed in the literature.
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Christman. L51577 Prediction of SCC Susceptibility Based on Mechanical Properties of Line Pipe Steels. Pipeline Research Council International, Inc. (PRCI), 1988. http://dx.doi.org/10.55274/r0010278.
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If a relationship between the deformation properties of a line pipe steel and its stress-corrosion cracking resistance can be established, then steels may be selected or designed for improved stress-corrosion resistance, based on their mechanical properties. Benefit: In this research program three line pipe steels, removed from long-term service, were examined to determine if there is a correlation between their mechanical properties and stress-corrosion cracking resistance. The hypothesis was that the steel with the greatest tendency for strain hardening, under cyclic and monotonic stress conditions would also have the highest threshold stress for stress-corrosion crack initiation. This hypothesis was verified by the laboratory experiments, which showed the steel with the greatest tendency for strain hardening to have the highest resistance to stress-corrosion. Two other steels, with distinctly lower resistance to plastic deformation, had lower threshold stresses for stress-corrosion. This observation is consistent with the present concept of stress-corrosion crack growth, which holds that crack tip dissolution, and hence crack propagation, occurs because localized plastic deformation ruptures passive films or prevents film formation resulting in crack growth. Result: The cyclic strain behavior of these three steels is consistent with their monotonic stress-strain curves. Both Steels A and B showed a point of extreme strain as the cyclic stress was increased. Their monotonic stress-strain curves both showed well pronounced yield points above which a considerable strain accompanied a small stress increment (low strain hardening). For both steels the rapid increase in cyclic strain occurred at approximately the elevated temperature yield point (\45 ksi for Steel A
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Schiller, Brandon, Tara Hutchinson, and Kelly Cobeen. Comparison of the Response of Small- and Large-Component Cripple Wall Specimens Tested under Simulated Seismic Loading (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, 2020. http://dx.doi.org/10.55461/iyca1674.
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This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4: Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. Two testing programs were conducted; the University of California, Berkeley (UC Berkeley) focused on large-component tests; and the University of California San Diego (UC San Diego) focused on small-component tests. The primary objectives of the tests were to develop descriptions of the load-deflection behavior of components and connections for use by Working Group 5 in developing numerical models and collect descriptions of damage at varying levels of drift for use by Working Group 6 in developing fragility functions. This report considers two large-component cripple wall tests performed at UC Berkeley and several small-component tests performed at UC San Diego that resembled the testing details of the large-component tests. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load on cripple wall assemblies. The details of the tests are representative of era-specific construction, specifically the most vulnerable pre-1945 construction. All cripple walls tested were 2 ft high and finished with stucco over horizontal lumber sheathing. Specimens were tested in both the retrofitted and unretrofitted condition. The large-component tests were constructed as three-dimensional components (with a 20-ft 4-ft floor plan) and included the cripple wall and a single-story superstructure above. The small-component tests were constructed as 12-ft-long two-dimensional components and included only the cripple wall. The pairing of small- and large-component tests was considered to make a direct comparison to determine the following: (1) how closely small-component specimen response could emulate the response of the large-component specimens; and (2) what boundary conditions in the small-component specimens led to the best match the response of the large-component specimens. The answers to these questions are intended to help identify best practices for the future design of cripple walls in residential housing, with particular interest in: (1) supporting the realistic design of small-component specimens that may capture the response large-component specimen response; and (2) to qualitatively determine where the small-component tests fall in the range of lower- to upper-bound estimation of strength and deformation capacity for the purposes of numerical modelling. Through these comparisons, the experiments will ultimately advance numerical modeling tools, which will in turn help generate seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings. To this end, details of the test specimens, measured as well as physical observations, and comparisons between the two test programs are summarized in this report.
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Denys, R. M. L51712 Fracture Behavior of Large-Diameter Girth Welds - Effect of Weld Metal Yield Strength Part II. Pipeline Research Council International, Inc. (PRCI), 1994. http://dx.doi.org/10.55274/r0010121.
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Fitness for purpose girth defect assessments assume the presence of a single defect. This assumption is not always fulfilled. Welds may contain many small defects. These defects, when considered individually and without interaction, are generally innocuous. However, this may be a false conclusion as to the true strength or deformation capacity of the weld because neighbouring imperfections or defects may interact and may be more severe than each individual imperfection. When non-destructive examinations reveal multiple defects, a defect recategorisation procedure has to be applied to determine whether neighbouring defects will interact other under load. The interaction criteria of BS PD6493, ASME Boiler and Pressure Vessel Code Section XI and the Japanese fitness-of-purpose code WES 2805 are based on a combination of linear elastic fracture mechanics calculations and engineering judgement. The PD6493 and ASME XI rules are based on the principle that the increase in the stress intensity magnification caused by interaction of neigbouring defects should be limited to 20% (PD 6493) and 6% (ASME XI), whereas the WES criterion is based on the principle that the stress intensity magnification or CTOD value of the interacting neighbouring defects should be limited to 20% of the shortest defect. As the fracture behaviour of line pipe girth welds differs from linear elastic behaviour, it is expected that the existing rules are not necessarily applicable for elastic-plastic or plastic material behaviours. This consideration suggests that there exist a need for developing criteria which permit plasticity effects to be incorporated. The mathematical treatment of multiple defects under elastic-plastic and or plastic fracture conditions is a complex issue because it is not possible to predict yielding behaviour and make a distinction between local and ligament collapse. Because of this limitation, it is thus necessary to employ large scale tensile tests in which the interaction effects can be reproduced. In persuing this approach, it is further possible: (a) to verify and establish the conservatism built into the existing interaction criteria. (b) to formulate alternative interaction criteria for elastic-plastic or plastic behavior. The goal of this study was to obtain information on the failure behavior of girth welds containing two coplanar fatigue pre-cracked defects. The results were correlated with tests on welds containing a single crack to determine the engineering significance of existing defect interaction rules under elastic-plastic and plastic fracture conditions.
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Lacerda Silva, P., G. R. Chalmers, A. M. M. Bustin, and R. M. Bustin. Gas geochemistry and the origins of H2S in the Montney Formation. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329794.
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The geology of the Montney Formation and the geochemistry of its produced fluids, including nonhydrocarbon gases such as hydrogen sulfide were investigated for both Alberta and BC play areas. Key parameters for understanding a complex petroleum system like the Montney play include changes in thickness, depth of burial, mass balance calculations, timing and magnitudes of paleotemperature exposure, as well as kerogen concentration and types to determine the distribution of hydrocarbon composition, H2S concentrations and CO2 concentrations. Results show that there is first-, second- and third- order variations in the maturation patterns that impact the hydrocarbon composition. Isomer ratio calculations for butane and propane, in combination with excess methane estimation from produced fluids, are powerful tools to highlight effects of migration in the hydrocarbon distribution. The present-day distribution of hydrocarbons is a result of fluid mixing between hydrocarbons generated in-situ with shorter-chained hydrocarbons (i.e., methane) migrated from deeper, more mature areas proximal to the deformation front, along structural elements like the Fort St. John Graben, as well as through areas of lithology with higher permeability. The BC Montney play appears to have hydrocarbon composition that reflects a larger contribution from in-situ generation, while the Montney play in Alberta has a higher proportion of its hydrocarbon volumes from migrated hydrocarbons. Hydrogen sulphide is observed to be laterally discontinuous and found in discrete zones or pockets. The locations of higher concentrations of hydrogen sulphide do not align with the sulphate-rich facies of the Charlie Lake Formation but can be seen to underlie areas of higher sulphate ion concentrations in the formation water. There is some alignment between CO2 and H2S, particularly south of Dawson Creek; however, the cross-plot of CO2 and H2S illustrates some deviation away from any correlation and there must be other processes at play (i.e., decomposition of kerogen or carbonate dissolution). The sources of sulphur in the produced H2S were investigated through isotopic analyses coupled with scanning electron microscopy, energy dispersive spectroscopy, and mineralogy by X-ray diffraction. The Montney Formation in BC can contain small discrete amounts of sulphur in the form of anhydrite as shown by XRD and SEM-EDX results. Sulphur isotopic analyses indicate that the most likely source of sulphur is from Triassic rocks, in particular, the Charlie Lake Formation, due to its close proximity, its high concentration of anhydrite (18-42%), and the evidence that dissolved sulphate ions migrated within the groundwater in fractures and transported anhydrite into the Halfway Formation and into the Montney Formation. The isotopic signature shows the sulphur isotopic ratio of the anhydrite in the Montney Formation is in the same range as the sulphur within the H2S gas and is a lighter ratio than what is found in Devonian anhydrite and H2S gas. This integrated study contributes to a better understanding of the hydrocarbon system for enhancing the efficiency of and optimizing the planning of drilling and production operations. Operators in BC should include mapping of the Charlie Lake evaporites and structural elements, three-dimensional seismic and sulphate ion concentrations in the connate water, when planning wells, in order to reduce the risk of encountering unexpected souring.
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Harris, L. B., P. Adiban, and E. Gloaguen. The role of enigmatic deep crustal and upper mantle structures on Au and magmatic Ni-Cu-PGE-Cr mineralization in the Superior Province. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328984.
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Aeromagnetic and ground gravity data for the Canadian Superior Province, filtered to extract long wavelength components and converted to pseudo-gravity, highlight deep, N-S trending regional-scale, rectilinear faults and margins to discrete, competent mafic or felsic granulite blocks (i.e. at high angles to most regional mapped structures and sub-province boundaries) with little to no surface expression that are spatially associated with lode ('orogenic') Au and Ni-Cu-PGE-Cr occurrences. Statistical and machine learning analysis of the Red Lake-Stormy Lake region in the W Superior Province confirms visual inspection for a greater correlation between Au deposits and these deep N-S structures than with mapped surface to upper crustal, generally E-W trending, faults and shear zones. Porphyry Au, Ni, Mo and U-Th showings are also located above these deep transverse faults. Several well defined concentric circular to elliptical structures identified in the Oxford Stull and Island Lake domains along the S boundary of the N Superior proto-craton, intersected by N- to NNW striking extensional fractures and/or faults that transect the W Superior Province, again with little to no direct surface or upper crustal expression, are spatially associated with magmatic Ni-Cu-PGE-Cr and related mineralization and Au occurrences. The McFaulds Lake greenstone belt, aka. 'Ring of Fire', constitutes only a small, crescent-shaped belt within one of these concentric features above which 2736-2733 Ma mafic-ultramafic intrusions bodies were intruded. The Big Trout Lake igneous complex that hosts Cr-Pt-Pd-Rh mineralization west of the Ring of Fire lies within a smaller concentrically ringed feature at depth and, near the Ontario-Manitoba border, the Lingman Lake Au deposit, numerous Au occurrences and minor Ni showings, are similarly located on concentric structures. Preliminary magnetotelluric (MT) interpretations suggest that these concentric structures appear to also have an expression in the subcontinental lithospheric mantle (SCLM) and that lithospheric mantle resistivity features trend N-S as well as E-W. With diameters between ca. 90 km to 185 km, elliptical structures are similar in size and internal geometry to coronae on Venus which geomorphological, radar, and gravity interpretations suggest formed above mantle upwellings. Emplacement of mafic-ultramafic bodies hosting Ni-Cr-PGE mineralization along these ringlike structures at their intersection with coeval deep transverse, ca. N-S faults (viz. phi structures), along with their location along the margin to the N Superior proto-craton, are consistent with secondary mantle upwellings portrayed in numerical models of a mantle plume beneath a craton with a deep lithospheric keel within a regional N-S compressional regime. Early, regional ca. N-S faults in the W Superior were reactivated as dilatational antithetic (secondary Riedel/R') sinistral shears during dextral transpression and as extensional fractures and/or normal faults during N-S shortening. The Kapuskasing structural zone or uplift likely represents Proterozoic reactivation of a similar deep transverse structure. Preservation of discrete faults in the deep crust beneath zones of distributed Neoarchean dextral transcurrent to transpressional shear zones in the present-day upper crust suggests a 'millefeuille' lithospheric strength profile, with competent SCLM, mid- to deep, and upper crustal layers. Mechanically strong deep crustal felsic and mafic granulite layers are attributed to dehydration and melt extraction. Intra-crustal decoupling along a ductile décollement in the W Superior led to the preservation of early-formed deep structures that acted as conduits for magma transport into the overlying crust and focussed hydrothermal fluid flow during regional deformation. Increase in the thickness of semi-brittle layers in the lower crust during regional metamorphism would result in an increase in fracturing and faulting in the lower crust, facilitating hydrothermal and carbonic fluid flow in pathways linking SCLM to the upper crust, a factor explaining the late timing for most orogenic Au. Results provide an important new dataset for regional prospectively mapping, especially with machine learning, and exploration targeting for Au and Ni-Cr-Cu-PGE mineralization. Results also furnish evidence for parautochthonous development of the S Superior Province during plume-related rifting and cannot be explained by conventional subduction and arc-accretion models.
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MECHANICAL PROPERTIES OF KINKED STEEL PLATES AND THEIR APPLICATIONS IN FRAME STRUCTURES. The Hong Kong Institute of Steel Construction, 2022. http://dx.doi.org/10.18057/icass2020.p.314.
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To effectively improve the ability of frame structures to comprehensively defend against seismic collapse and progressive collapse, this paper proposes a novel configuration, kinked steel plate (KP). The mechanical properties of KP were studied through test and numerical simulation. It is found that when KP is in tension, the resistance that can provide in the small deformation stage is lower, but it can provide a resistance equivalent to that of ordinary straight steel plates after being straightened. When KP in compression, the resistance that can provide is very small and can be ignored. Then, the application of KP in steel frame and reinforced concrete (RC) frame structure was discussed. For the application of KP in steel frames, KP is combined with the reduced beam section (RBS) connection, which can obtain an innovative connection (RBS-KP) containing KP. For the application of KP in RC frame, KP is added to RC beams, and a new type of RC beam containing KP is proposed. The seismic and progressive collapse performances of the RBS-KP connection and the new type of RC beam were studied by numerical simulation. Results illustrate that the RBS-KP connection has comparable seismic performance and greater resistance against progressive collapse than the RBS connection, as is the new type of RC beam relative to the RC beam.
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FEASIBILITY STUDY OF VISCOELASTIC HYBRID SELF-CENTERING BRACE (VSCB) FOR SEISMIC-RESISTANT STEEL FRAMES. The Hong Kong Institute of Steel Construction, 2022. http://dx.doi.org/10.18057/icass2020.p.113.
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The practicability of existing self-centering braces is largely limited by their small deformability and insufficient energy dissipation. This paper presents a new type of velocity-dependent self-centering brace called viscoelastic self-centering brace (VSCB), which employs viscoelastic dampers (VED) and SMA cables as the kernel elements. The SMA cables can offer large recoverable deformation, and the viscoelastic dampers, which are velocity-dependent, provide considerable energy dissipation under high-frequency loading excitations but tend to have less detrimental influence on the self-centering capability during the shakedown of the system. A comprehensive system-level analysis on three carefully designed prototype buildings was conducted, including a buckling restrained braced frame (BRBF), a pure self-centering braced frame (SCBF) and a viscoelastic self-centering braced frame (VSCBF). The results show that compared with the SCBF, the VSCBF maintains the benefit of small residual inter-story drift (RID) and in addition, exhibits obviously reduced peak inter-story drift (PID) and peak floor acceleration (PFA).
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A GENERALIZED METHOD FOR SHEAR CORRECTION FACTORS OF ARBITRARY THIN-WALLED SECTIONS. The Hong Kong Institute of Steel Construction, 2023. http://dx.doi.org/10.18057/ijasc.2023.19.3.4.
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Shear deformation may significantly affect the structural behaviours, especially for the structural members with small span-to-depth ratios. It is vital to consider the shear effects in the Direct Analysis Method (DAM) of thin-walled structures such that only the section capacity check is required in the evaluation of both member and system stability. However, there is lack of a general method to determine the shear correction factors of thin-walled cross-sections in various shapes and as a result DAM cannot be applied to the structures adopting these cross-sections. This paper proposes an innovative one-dimensional warping element model method to compute the shear correction factors of arbitrary thin-walled sections such as single open and closed sections, built-up sections, and large box sections with stiffeners. Also, the thin-walled cross-sections with non-uniform thickness can be considered by the proposed method. Several examples are investigated to validate the accuracy and efficiency of the proposed method against the analytical solution, conventional warping area element method and section analysis in ANSYS. Thus, this work provides a simple and practical method for direct analysis of thin-walled structures made of complex cross-sections with consideration of shear deformation.