多孔硅橡胶有限变形的弹性行为

针对孔隙度较大 (孔隙度大于 5 0 % )的硅橡胶材料在压缩情况下的大变形 ,提出了可描述此类可压橡胶材料力学行为的应变能密度函数 ,推导了硅橡胶材料的本构方程。利用硅橡胶材料的单轴压缩实验进行了材料参数拟合 ,讨论了多孔硅橡胶的孔隙度和体积变形对压缩性能的影响     

结构动力学模型中阻尼特性参数的修正

将结构分析计算的稳态位移响应和相应实测数据的差异映射为具有能量意义的误差范数，通过最小化该误差范数来修正与结构系统有关的阻尼特性参数．通过计算的或实测的频响函数获得稳态响应数据，使用的幅值在理论上完全包含了所有的复模态信息，参数值正过程采用迭代的方式．给出仿真算例，并对实验数据有噪声和无噪声两种情况进行了研究，结果表明方法合理且可行．     

一种饱和粘土本构模型的实验研究

本文紧密结合工程应用,基于三轴破坏实验和静水压缩实验结果,采用多项式函数给出了破坏包络线的具体形式,运用椭圆函数确定了加载函数曲线,从而提供一个简便易用,适用于一种饱和粘土的帽子模型。它与实验观测结果的吻合程度是令人满意的。     

Investigation of calculation method for anti-penetration of reactive power steel fiber concrete (RPC)

为了解决评估超高强活性粉末钢纤维混凝土的抗侵彻能力问题，根据混凝土在弹体侵彻过程中的介质状态及能量的分配关系，揭示了侵彻近区耗散能量结构与破碎区之间的比例尺度关系。由于近区介质的运动特性变形接近一维应变状态，受力类似于流体动力学状态，据此推导并简化了具有宽广的适用范围的侵彻计算公式，认为侵彻的深度主要由弹体的质量、形状、速度及靶体的强度、密度、断裂韧度、变形波速决定。通过多次的实弹试验，验证了公式的可靠性，得到了RPC的抗侵彻能力是普通混凝土的3倍的结论。     

花岗岩体中应力波传播计算的动态本构关系

在花岗岩体的弹性区域,对实测径向质点速度波形运用Lagrangian分析方法,得到了球面应力波传播的加载速率相关的应力应变关系曲线。由速率相关本构关系所作的计算结果表明,它能较正确地描述岩石中球面应力波传播过程中所体现的主要特征,即应力波峰值衰减指数大于1和波形剖面的展宽。     

30CrMnSiA 钢高温动态力学性质的实验研究

通过附有恒温加热炉的ＳＨＰＢ装置，测量了３０ＣｒＭｎＳｉＡ钢从室温到高温（６００℃）的动态（１．５１０３～４．０１０３ｓ－１）应力应变曲线，并利用一维应力波传播理论和传热学原理，修正了温度梯度场对测量的影响。结果表明，在实验温度２６～６００℃内，３０ＣｒＭｎＳｉＡ钢的温度软化规律可分为低温区和高温区；低温区流动应力随温度变化剧烈，高温区则缓慢。与准静态不同的是，高应变率下的转化温度有明显的提高。     

Limitations of the Phan-Thien non-linear network viscoelastic model

The failure of the Phan-Thien non-linear network viscoelastic model to predict realistic stress-strain relationships under certain conditions is illustrated in two examples. Care in the application of the model when applied in situations where high shear rates are expected is indicated.     

Phase equilibrium in non-fluids and non-fluid mixtures

A criterion of phase equilibrium for mixtures of materials with arbitrary symmetry (e.g. between solid and fluid or two solid mixture phases) is deduced using a rational thermodynamics approach. This criterion, known also as Maxwell relation, is expressed via the difference of chemical potential tensors (Eshelby tensors) on the singular surface dividing the bulk phases.The thermomechanical balance equations, the entropy inequality and the Maxwell relation for phase equilibrium are given first for the case of pure (one-constituent) materials of arbitrary symmetry and then for the case of mixtures (including chemically reacting ones) of arbitrary symmetry.In the special case of fluids it is shown that the chemical potential tensors reduce to the classical scalar chemical potentials and the Maxwell relations to the classical thermodynamic criterion for the phase equilibrium.     

Padé approximations for low-frequency motion in a pre-stressed compressible elastic layer

In this paper, we derive an asymptotic approximation of the low-frequency motion in a pre-stressed compressible elastic layer, valid in both long- and short-wave regimes. For this purpose, we shall use Padé approximations. Comparisons with numerical solutions are provided and show good agreement for all wavelength. Results appropriate to the classical linear isotropic case are also briefly provided.     

Dynamics of strings made of phase-transforming materials

This paper presents a theory to describe the dynamical behavior of a string made of a phase-transforming material like a shape-memory alloy. The study of phase boundaries, the driving force acting on them and the kinetic relation governing their propagation is of central concern. The paper proposes a qualitative experimental test of the notion of a kinetic relation, as well as a simple experimental method for measuring it quantitatively. It presents a numerical method for studying general initial and boundary value problems in strings, and concludes by exploring the use of phase transforming strings to generate motion at very small scales.