水下拖曳柔索的动力学理论模型研究

建立了水下拖曳柔索系统的三维有线段模型,该模型由一系列具有不同物理特性的铰接刚性杆组成,缆索可以包含多个开环或闭环分支。讨论了流体阻力、流体附加质量和流体静压力的影响,分析比较了附加质量与系统本身惯性的关系。该模型可用于水下拖曳系统的动力学仿真。

荷载横向扩散式组砌道面力学理论模型分析

为了改善现有联锁块道面的荷载横向扩散能力并提高道面的承载能力,设计开发了具有较大尺寸的荷载横向扩散式组砌道面,并分析了组砌道面受荷时边界条件变化过程,提出了道面两阶段边界条件计算理论,并依据这两阶段边界条件建立了组砌道面的挠曲微分方程表达式。

基于连续介质力学的接触轮橡胶超弹性模型研究

针对橡胶超弹性导致恒切深砂带的磨削材料去除深度与理论材料去除深度产生误差的问题,基于连续介质力学理论模型的本构方程对橡胶超弹性特性下的应力-应变关系进行分析,对比确定了适用于钢轨打磨作业的Mooney-Rivlin理论模型,揭示了橡胶超弹性和线弹性的关系和差异,利用仿真验证了上述理论模型的正确性。

带竖向连梁的偏心支撑组合框架理论研究

带竖向连梁的偏心支撑组合框架具有良好的力学性能,是一种高效的耗能减震结构体系,但由于试验研究的数量有限,仅从单个构件试验并不能完全证明该结构体系的优越性和适用性。该文对带竖向连梁的偏心支撑组合框架展开理论研究,详细分析了各设计参数对结构抗震性能的影响。首先,该文建立该结构体系的结构力学理论模型,推导侧向荷载作用下结构的内力分布结果与变形分布结果,并提出该结构的理论骨架曲线,给出理论骨架曲线关键点的计算方法,与试验结果吻合良好。根据该文建立的理论模型,可计算出在不同侧向荷载作用下,结构的内力分布与变形模式。此外,理论模型分析的结果显示,在引入偏心支撑构件后,原组合框架的梁端和柱端的内力增加,跨中框架梁内力增加,混凝土板的损伤增加,结构的侧向刚度明显提升,与试验结果分析得到的结论完全一致,进一步验证理论模型的准确性。

汽车轮胎理论模型的分析

对汽车轮胎理论模型发展中具有代表性的Ｆｉａｌａ、改进Ｆｉａｌａ、Ｓａｋａｉ、Ｇ．Ｇｉｍ等４种轮胎理论模型进行了介绍，并结合道路试验的实验数据对上述理论模型进行了综合分析。

经编间隔织物增强硅橡胶基复合材料压缩行为的数学模型

为研究经编间隔织物增强硅橡胶基复合材料(silicone-rubber-matrix composite reinforced by warp-knitted spacer fabric,SWSF)在20%变形内的压缩机理,基于Euler-Bernoulli梁理论和Spence不变量本构理论,建立了SWSF的压缩细观力学理论模型,该模型由硅橡胶的力学模型和经编间隔织物(warp-knitted spacer fabric,WSF)的压缩模型组成。根据相应力学试验的结果,在MATLAB软件中计算了SWSF压缩细观力学理论模型的参数。利用复合材料的压缩试验,验证压缩细观力学理论模型的可行性。结果表明,建立的细观压缩力学理论模型能够较好地模拟SWSF试样在20%变形内的压缩行为。此外,该理论模型有助于理解SWSF的压缩机理,优化SWSF的产品设计。

一种树木移植机器的设计与理论分析

随着我国城市文明建设的推进，成树绿化需求也越来越大，而树木移植机使得成树移植过程实现了标准化和模块化，大大提升了工作效率。本文首先设计了一种复合式的树木移植机械设备并对该机器的工作过程进行详细的介绍。该设备由车体、摆臂、车厢、树木起吊装置四部分组成，其中存在的两个机械手能分别完成树木挖掘和树木固定转移的功能；通过对树木移植机下铲阻力的探讨，并结合下铲阻力的经验公式，系统地分析了下铲阻力变化规律和影响因素，用以指导选择合适的动力设备和液压设备。

Bio-SR工艺吸收液Fe^(2+)再生动力学研究

通过实验研究,分析了反应温度和溶液pH值对氧化亚铁硫杆菌氧化Fe2+的影响,确定了氧化亚铁硫杆菌保持最佳氧化活性的优化环境条件:pH值2.0,温度30℃。依据酶促反应的中间产物理论,推导出氧化亚铁硫杆菌对Fe2+氧化的动力学模型。在考虑底物抑制因素基础上,利用实验所得数据进行拟合计算,得出了氧化亚铁硫杆菌氧化Fe2+的表观速率方程。该实验为Bio-SR工艺Fe2+再生生物反应器的优化设计提供了一些指导性数据。

多荷载耦合作用下立井井壁潜在破坏区的确定

首先采用弹性理论对立井井壁进行了分析,建立了井壁破坏的理论模型,进而采用通用有限元软件ANSYS,建立了立井井壁的大型三维分离式有限元数值模型。运用这两种模型详细研究了多种荷载耦合作用对立井井壁的影响,多种荷载包括:随深度变化的土压力、随时间变化的疏水附加力以及井壁自身重量。确定了立井井壁在这三种荷载综合作用下的应力、应变集中区,论证了井壁破坏理论中疏水附加力理论的正确性,对井壁设计理论以及加固区域的确定提供了一定的理论指导。本文有限元模型的建立方法以及得到的结论,在一定程度上丰富了立井井壁理论的内容,增加了立井井壁理论研究的方法,促进了井壁附加应力说的发展。

新型转炉炉壳与托圈连接装置的交变载荷计算与特性分析

构建了新型转炉炉壳与托圈连接装置SHBar(Slide Hinge Bar)的空炉动力学理论模型,并采用商业动力学软件验证其正确性。在此理论模型的基础上,研究了转炉带钢水倾动的SHBar连接单元的受力。通过实例验证,分析出当空炉旋转时三个连接单元的受力均是周期确定的交变载荷,以及每个连接单元受力幅值随相位角的变化规律;并进一步分析了转炉带钢水倾动时,三个连接单元的载荷在钢水的流动与倾动过程中所受的影响及其特性变化。研究结果为SHBar的优化设计提供了可靠地理论依据。

基于绝对式的压力电测系统准静态校准方法分析

压力电测法能反映压力随时间变化的全过程,数据实时性强,含有的信息量大,应用于武器系统的设计、研制及理论弹道学的分析中。国内外广泛采用的压电式压力电测系统虽然具有动态特性良好等优点,但由于其低频或零频特性比较差,因此需对电测系统进行准静态校准以获取测试系统的工作特性参数等指标。文中简要介绍了准静态校准装置,即落锤液压动标装置的工作原理,阐述了绝对式准静态校准的原理,通过建立力-压力动力学理论模型,从理论上推导出力与压力之间的关系式,从而证明了力监测压力的可行性。

链环式超越离合器高载荷下的内应力分析

链环式超越离合器是一种新型摩擦式超越离合器 ,它的一个重要的特性就是具有比传统超越离合器更高的承载能力[1] 。本文通过建立链环式超越离合器的整体模型 ,得到了链环式超越离合器的理论力学模型 ,并进一步建立了其弹性力学模型 ,对模型求解后得到了链环式超越离合器的内应力分布 ,并通过试验证明结论。展示了链环式超越离合器动应力求解的一般过程 ,并进一步证明了其高承载能力的原因 。

Thermodynamic model of lead oxide activity in PbO-CaO-SiO_2-FeO-Fe_2O_3 slag system

According to the ion and molecule coexistence theory, a thermodynamic model of lead oxide activity in PbO-CaO-SiO2-FeO-Fe2O3 slag system was established at the temperature of 1273-1733 K. The activities of Pb O in slag were calculated, and their equal activity curves were plotted. The influences of slag basicity Q, iron oxide rate R and temperature T on activity NPb O and activity coefficient γPbO were also investigated. Results show that the calculated values of γPb O are in good agreement with the reported experimental data, showing that the model can wholly embody the slag structural characteristics. NPbO departures positively from Raoult values, and increases with increasing Pb O content in slag but changes little with T. γPbO increases with increasing Q, and goes through the maximum with increasing R for basic slag（Q0.3）. Results can be applied to the thermodynamic research and operational optimization of modern lead smelting technologies.

A Theoretical Model on Solvus Line Prediction of Film and Its Application in Nanogranular Al-Cu System

A theoretical model on the solvus line prediction of a film was proposed and applied to a nanogranular A1-Cu system. The calculation results show that the solvus line of solute Cu will markedly lower with the decrease of grain size, namely, the starting temperature of θ （Al2Cu） precipitation in a nanogranular A1-Cu film will markedly lower than that of conventional coarse grain alloy with the same Cu concentration, and the precipitation temperatures calculated are comparable with the experimental ones. The theoretical model can be simply used to calculate the starting temperature of precipitation in A1-Cu films under three states： ① films with substrate; ②films without substrate; ③ultrafine grain bulk alloy. As a result, the model is universal, moreover, can be, in principle, used to predict precipitation temperature in other systems.

Numerical analysis on coal-breaking process under high pressure water jet

Based on the theory of nonlinear dynamic finite element,the control equation ofcoal and water jet was acquired in the coal breaking process under a water jet.The calculationmodel of coal breaking under a water jet was established;the fluid-structure couplingof water jet and coal was implemented by penalty function and convection calculation.The dynamic process of coal breaking under a water jet was simulated and analyzed bycombining the united fracture criteria of the maximum tensile strain and the maximal shearstrain in the two cases of damage to coal and damage failure to coal.

A Molecular Thermodynamic Model for Interfacial Tension in Surfactant-Oil-Water System

An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular ther-modynamic model has been proposed. The interfacial tension of surfactant-oil-water systems can be calculated from the surface tensions of pure oil and water by this model. The interfacial tension data for sodium dodecyl sulphate-heptane-water system, polyoxyethylene n-octylphenol-heptane-water system and hexadecyl trimethyl ammonium bromide-heptane-water system have been correlated. By using the adjustable parameters obtained, the interfacial tensions of these systems at other temperatures have been predicted. Both the correlated and the predicted values are satisfactory.

Analytical solution of a circular lined tunnel with alterable mechanical property under hydrostatic stress and internal pressure

The influence of the interaction between surrounding rock and lining on the long-term behaviour of a tunnel in service is significant.In this paper,we proposed a mechanical model of the circular lined tunnel with the alterable mechanical property under hydrostatic stress and radially inner surface pressure of the lining.The alterable mechanical properties of the surrounding rock and the lining are embodied by the changing of their elasticity modulus with service time and radial direction of the tunnel,respectively.The proposed mechanical model is successfully validated by comparison with the existing theoretical models and the numerical simulation,respectively.The influences of the main parameters of the proposed mechanical model,such as the radial power-law indexes and the time-varying coefficients of the surrounding rock and the lining,as well as the radially inner surface pressure of the lining,on the interface displacement and pressure between surrounding rock and lining are investigated.The research results can provide some valuable references for timely diagnosis and correct evaluation of the long-term behaviours of a tunnel in service.

Wave Drift Forces on Two Floating Bodies Arranged Side by Side

An innovative hydrodynamic theory and numerical model were developed to help improve the efficiency, accuracy, and convergence of the numerical prediction of wave drift forces on two side-by-side deepwater floating bodies. The wave drift forces were expressed by the double integration of source strength and the corresponding Green function on the body surface, which is consistent with the far field formula based on momentum conservation and sharing the advantage of near field calculations providing the drift force on each body. Numerical results were validated through comparing the general far field model and pressure integral model, as well as the middle field model developed usin^z the software HydroStar.

Mechanical model of control of key strata in deep mining

Based on the characteristic of deep rock layers and the theory of key strata,we analysed elastic mechanical characteristics of key strata by using elastic plate theory.The results show that the deformation and distribution of internal forces of key strata vary with different mine boundary conditions.The boundary values of key strata with three point boundaries and one fixed boundary is greater than that with four fixed boundaries.Considering the rheology of key strata under low stress conditions,we selected a generalized Kelvin model to analyse the rheology characteristics of the key strata and discovered their instantaneous elastic phases.The rate of deformation decreased over time to the point where the key strata reached stability.But over this time,the effect on deformation became very clear. For high stress conditions,we chose a Burgers model and found deformation of key strata in the form of attenuation and steady-state creep and although the rate of deformation remained constant,secondary creep was obvious,causing instability in the system.As well,we analysed the effect of creep buckling and derived a relation between buckling force and time.

Solvable Catalyzed Birth-Death-Exchange Competition Model of Three Species

A competition model of three species in exchange-driven aggregation growth is proposed. In the model, three distinct aggregates grow by exchange of monomers and in parallel, birth of species A is catalyzed by species B and death of species A is catalyzed by species C. The rates for both catalysis processes are proportional to kj^v and ky respectively, where ν（ω） is a parameter reflecting the dependence of the catalysis reaction rate of birth （death） on the catalyst aggregate＇s size. The kinetic evolution behaviors of the three species are investigated by the rate equation approach based on the mean-field theory： The form of the aggregate size distribution of A-species αk（t） is found to be dependent crucially on the two catalysis rate kernel parameters. The results show that （i） in case of ν ≤O, the form of ak （t） mainly depends on the competition between self-exchange of species A and species-C-catalyzed death of species A; （ii） in case of ν 〉 0, the form of αk（t） mainly depends on the competition between species-B-catalyzed birth of species A and species-C-catalyzed death of species A.