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Modeling ocean wave propagation under sea ice covers

Acta Mech.nica Sinica 2015年第1期31卷 1-15页

作者： Xin Zh.o hayley h. shen Sukun Ch.ng Department of Civil and Environmental Engineering Clarkson University

Operational ocean wave models need to work globally, yet current ocean wave models can only treat ice covered regions crudely. Th. purpose of th.s paper is to provide a brief overview of ice effects on wave propagation and different research.meth.dology used in studying th.se effects. Based on its proximity to land or sea, sea ice can be classified as： landfast ice zone, sh.ar zone, and th. marginal ice zone. All ice covers attenuate wave energy. Only long swells can penetrate deep into an ice cover. Being closest to open water, wave propagation in th. marginal ice zone is th. most complex to model. Th. ph.sical appearance of sea ice in th. marginal ice zone varies. Grease ice, pancake ice, brash.ice, floe aggregates, and continuous ice sh.et may be found in th.s zone at different times and locations. Th.se types of ice are formed under different th.rmalmech.nical forcing. Th.re are th.ee classic models th.t describe wave propagation th.ough.an idealized ice cover： mass loading, th.n elastic plate, and viscous layer models. From ph.si cal arguments we may conjecture th.t mass loading model is suitable for disjoint aggregates of ice floes much.smaller th.n th. wavelength. th.n elastic plate model is suitable for a con tinuous ice sh.et, and th. viscous layer model is suitable for grease ice. For different sea ice types we may need different wave ice interaction models. A recently proposed viscoelas tic model is able to synth.size all th.ee classic models into one. Under suitable limiting conditions it converges to th. th.ee previous models. Th. complete th.oretical framework for evaluating wave propagation th.ough.various ice covers need to be implemented in th. operational ocean wave models. In th.s review, we introduce th. sea ice types, previous wave ice interaction models, wave attenuation mech.nisms,th. meth.ds to calculate wave reflection and transmission between different ice covers, and th. effect of ice floe breaking on sh.ping th. sea ice morph.logy. Labora

关键词： Ocean waves Sea ice Cryosph.ric ch.nge

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基于颗粒组构特性的散体材料本构模型研究

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岩土力学 2009年第S1期30卷 93-98页

作者：高政国 hayley h. shen 北京航空航天大学交通科学与工程学院北京100191 美国clarkson大学土木环境系美国13699

通过散体介质材料单元颗粒排列组构表达的细观结构力学关系,建立了用颗粒密集度、颗粒排列组构关系和颗粒间摩擦特性等非连续介质材料特性参数描述的散体介质材料本构模型,从而实现散体介质材料宏观连续介质描述的等效应力表达。通过该... 详细信息

通过散体介质材料单元颗粒排列组构表达的细观结构力学关系,建立了用颗粒密集度、颗粒排列组构关系和颗粒间摩擦特性等非连续介质材料特性参数描述的散体介质材料本构模型,从而实现散体介质材料宏观连续介质描述的等效应力表达。通过该模型可采用数值方法进行散体介质材料准静态情况下的力学特性分析。文中最后基于有限元软件ABAQUS,进行了该本构模型的二次开发。数值算例结果验证了所建立散体介质材料本构模型的适用性。

关键词：散体介质材料本构模型颗粒排列组构

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Ch.racteristics of temporal-spatial parameters in quasi-solid-fluid ph.se transition of granular materials

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Ch.nese Science Bulletin 2006年第6期51卷 646-654页

作者： JI Sh.nying shen h.hayley State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116023 China Department of Civil and Environmental Engineering Clarkson University Potsdam NY 13699-5710 USA

Th. quasi-solid-fluid ph.se transition of granular materials is closely related to th. sh.ar rate and solid concentration in addition to th.ir intrinsic properties. Th. contact duration and th. coordination number are two important temporal-spatial parame-ters to describe th. granular interaction in ph.se transition. In th.s study, ch.racteristics of th. contact duration and th. coordination number associated with.th. transition processes are determined using a 3D discrete element model under different sh.ar rates and concentrations. Th. resulting macroscopic stress and strain-rate relations are discussed. Th. temporal and spatial parameters provide a linkage between th. macroscopic constitutive law and inter- particle micromech.nics.

关键词：颗粒材料粒状流动力学准固-液相变时空参数

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A viscoelastic-plastic constitutive model with.Moh.-Coulomb yielding criterion for sea ice dynamics

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Acta Oceanologica Sinica 2005年第4期24卷 54-65页

作者： JI Sh.nying shen h.ng Tao WANG Zh.lian shen h.hayley YUE Qianjin State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116023 China Department of Civil and Environmental Engineering Clarkson University Potsdam New York 13699-5710 USA

A new viscoelastic-plastic （VEP） constitutive model for sea ice dynamics was developed based on continuum mech.nics. Th.s model consists of four components： Kelvin-Vogit viscoelastic model, Moh.-Coulomb yielding criterion, associated normality flow rule for plastic reh.lolgy, and h.drostatic pressure. Th. numerical simulations for ice motion in an idealized rectangular basin were made using smooth.d particle h.drodynamics （SPh. meth.d, and compared with.th. analytical solution as well as th.se based on th. modified viscous plastic（VP） model and static ice jam th.ory. Th.se simulations sh.w th.t th. new VEP model can simulate ice dynamics accurately. Th. new constitutive model was furth.r applied to simulate ice dynamics of th. Boh.i Sea and compared with.th. traditional VP, and modified VP models. Th. results of th. VEP model are compared better with.th. satellite remote images, and th. simulated ice conditions in th. JZ20-2 oil platform area were more reasonable.

关键词： sea ice dynamics constitutive model viscous plasticity viscoelastic-plastic model Molar-Coulomb criterion

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Scale dependence of direct sh.ar tests

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Ch.nese Science Bulletin 2009年第23期54卷 4337-4348页

作者： Zh.U Qiang shen hayley h.h.LENBROOK Brian T Zh.NG h.ngWu Department of Engineering Mech.nics Dalian University of Technology Dalian 116024 China Department of Civil and Environmental Engineering Clarkson University Potsdam NY 13699-5710 USA Department of Mech.nical and Aeronautical Engineering Clarkson University Potsdam NY 13699-5725 USA

Direct sh.ar test h.s been widely used to measure th. sh.ar strength.of soils and oth.r particulate materials in industry because of its simplicity. h.wever, th. results can be dependent on th. specimen size. Th. ASTM (American Society for Testing and Materials) publications suggest th.t for testing soils th. sh.ar box sh.uld be at least ten times th. diameter of th. largest particle and th. h.igh. of th. box sh.uld be no more th.n h.lf of its diameter. Th.se guidelines are empirically based. A series of two-dimensional numerical direct sh.ar tests are performed to investigate th.s scaling effect. By analyzing th. bulk friction, particle translation and rotation, percentage of sliding, average volume (area) and sh.ar strain and th. evolution of th. sh.ar band, we find th.t th. traditional guidelines for direct sh.ar tests are questionable. Scaling dependency of bulk friction on th. property of granular materials is clearly present. Our current analysis points out th.t th. scaling effects can vary significantly depending on th. particle properties oth.r th.n th.ir sizes. Of all th. parameters we observed, particle rotation appears to h.ve a decisive correlation with.th. bulk friction. Formation of a sh.ar band is universal. As th. sh.aring progresses, particle rotation begins to concentrate near th. sh.ar plane. By defining th. width.of a sh.ar band as th. standard deviation of th. distribution of translational gradient or th. standard deviation of th. distribution of particle rotation, quantitative evolutions of sh.ar band are presented. Both.measures of th. sh.ar band width.dropped rapidly during pre-failure stage. After peak stress both.measures begin to approach.steady state as th. bulk friction stabilizes to th. residual stage. Th.se observations suggest th.t structure formation inside th. sh.ar band controls th. scaling effect.

关键词：直接剪切试验测试土力学土工试验

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Granular pressure–temperature relation during regime ch.nge in a simple sh.ar state

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Th.oretical & Applied Mech.nics Letters 2013年第2期3卷 21-24页

作者： hayley shen Department of Civil and Environmental Engineering Clarkson University

In a recent study, a regime ch.rt was establish.d for sh.ared granular systems. For a soft particle system under simple sh.ar, th. internal stress sh.wed a range of rate dependency. As th. particle concentration increased, th. system transitioned from a kinetic gas to a plastic solid. Th.s transition was gradual for low stiffness systems but became more abrupt as th. stiffness increased. In th.s study, th. relationsh.p between th. granular temperature and pressure is investigated for th. same system of particles. Th. granular temperature is defined as th. average kinetic energy per unit volume and th. pressure is defined as th. trace of th. stress tensor. It is found th.t th.s pressure-temperature （P-T） curve depicts a sh.rp turn wh.n th. system moves away from th. kinetic gas regime. h.wever, no signature is found in th. P-T relationsh.p in oth.r regimes.

关键词： granular materials regime ch.nge pressure temperature

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Pressure-Temperature Relation during Regime Ch.nge in Dry Sh.ared Granular Materials

Pressure-Temperature Relation during Regime Change in Dry Sh...

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2012颗粒材料计算力学会议

作者： shen hayley h. Clarkson University

In a recent study a regime ch.rt was establish.d for sh.ared granular systems using discrete element simulations. For a soft particle system under simple sh.ar th. internal stress sh.wed a range of rate dependency. As th. particle concentration increased th. system transitioned from a kinetic gas to a plastic solid. Th.s transition was gradual for low stiffness particle systems but became more abrupt for h.gh.stiffness systems. Th. contour plot of th. power index for th. rate dependency consisted of a family of -sh.pe curves. In th.s study, th. relationsh.p between th. granular temperature and pressure is investigated for th. same system of particles. Th. granular temperature is defined as th. average kinetic energy per unit volume and th. pressure is defined as th. trace of th. stress tensor. It is found th.t th.s pressure-temperature curve depicts a drastic turn wh.n th. rate dependency index drops below 1. Th.t is, wh.n th. system moves away from th. kinetic gas regime th. pressure-temperature relation ch.nges suddenly. h.wever, no oth.r signature is found in th. P-T relationsh.p in oth.r regimes. In pursuit of an equivalent th.rmodynamic description for a dissipative system such.as th. sh.ared granular assembly, oth.r quantities beyond pressure and temperature must be introduced.

关键词： dry sh.ared granular materials regime ch.nge pressure temperature

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颗粒介质在类固-液相变过程中的时空参数特性

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科学通报 2006年第3期51卷 255-262页

作者：季顺迎 hayley h.shen 大连理工大学工业装备结构分析国家重点实验室 Department of Civil and Environmental Engineering Clarkson UniversityPotsdamNY13699-5710USA

颗粒介质的类固-液相变过程除受材料性质影响外,还与其运动速率和密集度有密切关系,而接触时间数和配位数是表征该相变过程中颗粒间相互作用的重要时间和空间参量.本文采用三维离散元方法对不同切变速率和密集度下颗粒介质的动力学行为... 详细信息

颗粒介质的类固-液相变过程除受材料性质影响外,还与其运动速率和密集度有密切关系,而接触时间数和配位数是表征该相变过程中颗粒间相互作用的重要时间和空间参量.本文采用三维离散元方法对不同切变速率和密集度下颗粒介质的动力学行为进行了数值模拟,确定了颗粒材料在类固-液相变过程中接触时间数和配位数的参数特性和演化过程,并结合宏观应力的分布特性,进一步确定了颗粒介质在液态和固态相互转化中的动力学机理,讨论了颗粒介质在由快速流动向慢速、准静态转化的相变过程.通过对颗粒单元相互作用的细观数值模拟,获取了颗粒介质在宏观上的动力学行为,为研究其在不同相态下的本构模型提供了依据.

关键词：颗粒流体动力学类固-液相变配位数接触时间数宏观应力

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Ph.sics of Granular Flows

Physics of Granular Flows

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软件物质物理研讨会

作者： hayley shen

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基于Moh.-Coulomb准则的黏弹-塑性海冰动力学本构模型

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海洋学报 2005年第4期27卷 19-30页

作者：季顺迎沈洪道王志联奚海莉岳前进大连理工大学工业装备结构分析国家重点实验室辽宁大连116023 美国Clarkson大学土木与环境工程系 potsdam纽约136995710

针对中小尺度下海冰动力作用过程中的漂移、重叠和堆积特征,在连续介质力学基础上建立了一个黏弹塑性海冰动力学本构模型.该模型主要包括四部分,即海冰在屈服前的Kelvin Vogit黏弹模型、海冰塑性屈服的Moh. Coulomb准则、屈服后相关联... 详细信息

针对中小尺度下海冰动力作用过程中的漂移、重叠和堆积特征,在连续介质力学基础上建立了一个黏弹塑性海冰动力学本构模型.该模型主要包括四部分,即海冰在屈服前的Kelvin Vogit黏弹模型、海冰塑性屈服的Moh. Coulomb准则、屈服后相关联的正交流动法则和影响海冰强度的静水压力.采用黏弹塑性本构模型对规则海域内的海冰堆积过程进行了数值试验,其结果与传统黏塑性模型、改进的黏塑性模型和经典冰坝理论的解析解相符,可合理地模拟海冰堆积的动力过程.为进一步检验该黏弹塑性本构模型的适用性,对渤海海冰的动力过程进行了48h.数值模拟,计算结果与海冰卫星遥感现场观测资料一致.通过与传统的黏塑性和改进的黏塑性模型结果的对比分析,进一步验证了黏弹塑性模型在中小尺度海冰动力学模拟中的可靠性.在以上海冰堆积的数值试验和渤海海冰动力学模拟中均采用了光滑质点流体动力学(SPh.方法.

关键词：海冰动力学本构模型黏塑性黏弹-塑性 Moh.—Coulomb准则

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