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1.
杆系结构弹性波传播的实验研究 总被引:2,自引:0,他引:2
利用SHPB装置,用空气枪加载就35CrMnSi钢组成的杆系结构(平面L型、空间直角坐标Y型)受冲击载荷作用的弹性波传播进行了实验研究,给出了一些力学现象,并利用广义特征线法给出了理论与实验的比较曲线,得到了一些有益的结论。 相似文献
2.
利用SHPB装置,用空气枪加载就35CrMnSi钢组成的平面杆系结构受冲击载荷作用的弹性波传播进行了实验研究,给出了一些力学现象,并利用广义特征线法给出了理论与实验的比较曲线,得到了一些有益的结论. 相似文献
3.
基于广义胡克定律及混和变量弹性波方程,解析求得各层介质位移位,应力传播矩阵,给出了直角坐标系各向异性层状介质中弹性波的传播矩阵解法,该方法适用于非轴对称各向异性和点源作用,较好地解决了数值计算中有效数字精度损失问题,数值结果表明,计算效率,准确性及稳定性均较好。 相似文献
4.
利用 S H P B装置,用空气枪加载就 35 Cr Mn Si钢组成的 L型杆系结构受横向冲击载荷作用的弹性波传播进行了实验研究,给出了一些力学现象,并与轴向冲击的实验进行了对比,得到了有益的结论。 相似文献
5.
刚架结构中瞬态波的传播 总被引:7,自引:0,他引:7
在改进回传矩阵法的基础上 ,引入节点质量阻尼模型 ,结合射线展开技术 ,研究刚架结构中的弹性瞬态波的传播。根据分析结果可以看出 ,节点质量对弹性波的传播影响不大 ,节点阻尼对弹性波的传播影响很大。如果选取合适的节点 ,就可以阻碍波在结构局部中的传播 ,达到结构局部控制的目的。刚架结构中的弹性瞬态波的传播 ,可以对大型刚架结构的无损检测提供一定的帮助。 相似文献
6.
弹性波传播理论一些问题的研究现状和展望 总被引:4,自引:0,他引:4
本文简要地阐述了弹性波传播的一些基本理论,如位移势,表现定理及特征线理论等,并评述了两个领域内的问题。一为无限介质,半无限介质及层状介质中波的传播问题,重点在于地震波传播问题的解法。另一个领域为弹性波的绕射和散射。这一问题在动断裂、无损探伤及地震学中有重要的应用。评迷的重点是解题方法。 对本学科将来的发展也作了展望。认为反问题,随机波理论和在新技术领域中的应用是发展方向。在不少工程领域中的应用将越来越多地不能局限在弹性波范围内 相似文献
7.
弹性波在饱和土层中的传播 总被引:21,自引:1,他引:21
本文在扼要综述以往有关的研究成果以后,通过一定的假设,推导出饱和土连续条件方程以及考虑土骨架与孔隙水之间耦合效应的动力平衡方程,从而得到一组饱和土层中的弹性波动方程,其中只应用了具有明确意义的土骨架和孔隙水力学参数。分析表明,无限饱和土层中可存在两种P波和一种S波;在渗透性很好的饱和土层中,孔隙水波速度最大可达到水中波速的3~(1/2)倍;在渗透性极差的饱和土中,两种P波同速,且可接近或大于水中波速;土的渗透性对S波的影响不如P波的显著,以此,可近似解释一些试验现象,对利用波速法测得合理的饱和土层特性参数以及相关学科也具有理论与应用价值。 相似文献
8.
反射全息干涉和反射光弹性方法应用于应力波传播 总被引:1,自引:0,他引:1
在应力波传播过程中,半无限平面的聚酯模型在一个截面上的主应力分布解被实验所确定。应力波由摆式重锤的冲击所产生。应用两个外部适当的触发装置触发一个双脉冲红宝石激光器(0.5焦耳/每脉冲)。模型的一个表面做成全反射面,利用对这个表面的反射式全息干涉法和通过模型的另一表面的反射式光弹性法可以记录冲击后不同时间延迟的等和线与等差线条纹图。 相似文献
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10.
对应力波在变截面体中的传播特性进行了理论研究和数值分析。以杆中一维纵波波动理论和谐波分析法为基础,研究截面变化所导致的应力波的波形弥散和波幅变化。推导了与截面变化相关的应力波演化因子,并对由于截面变化所造成的几何弥散等二维效应进行了分析,同时计算了变截面体的几何特征参数和截面变化等因素影响应力波演化规律的特点。 相似文献
11.
Maria Luisa Tonon 《Journal of Elasticity》2002,69(1-3):15-39
This paper deals with the propagation of acceleration waves in constrained linear elastic materials, within the framework
of the so-called linearized finite theory of elasticity, as defined by Hoger and Johnson in [12, 13]. In this theory, the
constitutive equations are obtained by linearization of the corresponding finite constitutive equations with respect to the
displacement gradient and significantly differ from those of the classical linear theory of elasticity. First, following the
same procedure used for the constitutive equations, the amplitude condition for a general constraint is obtained. Explicit
results for the amplitude condition for incompressible and inextensible materials are also given and compared with those of
the classical linear theory of elasticity. In particular, it is shown that for the constraint of incompressibility the classical
linear elasticity provides an amplitude condition that, coincidently, is correct, while for the constraint of inextensibility
the disagreement is first order in the displacement gradient. Then, the propagation condition for the constraints of incompressibility
and inextensibility is studied. For incompressible materials the propagation condition is solved and explicit values for the
squares of the speeds of propagation are obtained. For inextensible materials the propagation condition is solved for plane
acceleration waves propagating into a homogeneously strained material. For both constraints, it is shown that the squares
of the speeds of propagation depend by terms that are first order in the displacement gradient, while in classical linear
elasticity they are constant.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Consideration is given to the nonlinear theory of elastic waves with cubic nonlinearity. This nonlinearity is separated out, and the interaction of four harmonic waves is studied. The method of slowly varying amplitudes is used. The shortened and evolution equations, the first integrals of these equations (Manley–Rowe relations), and energy balance law for a set of four interacting waves (quadruplet) are derived. The interaction of waves is described using the wavefront reversal scheme 相似文献
13.
The structural theory of waves and vibrations in periodically inhomogeneous media is set out. Relevant research results are presented. Emphasis is on the principles of the theory, surface waves, and other surface effects 相似文献
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15.
The dispersion of harmonic waves, propagating along a principal direction in a pre-stressed, compressible elastic plate, is investigated in respect of the most general isotropic strain-energy function. Different cases, dependent on the choice of material parameters and pre-stress, are analysed. A complete long and short wave asymptotic analysis is carried out, with the approximations obtained giving phase speed (and frequency) as explicit functions of wave and mode number. Various wave fronts, both associated with the short wave limit of harmonics and arising through the combination of harmonics in a narrow wave speed region, are discussed. It is mentioned that the case of high compressibility is of particular interest. In contrast with the classical (un-strained) case, the longitudinal body wave speed may be less than the corresponding shear wave speed. In consequence, the short wave limit of all harmonics may be the appropriate longitudinal wave speed; contrasting with the classical case for which this limit is necessarily associated with a shear wave front. A further possible short wave limit is also shown to exist for which the associated wave normal has a component in the direction normal to the plate. Particularly novel numerical results are presented when the longitudinal and shear wave speeds are equal. The analysis is illustrated by numerical calculations for various strain-energy functions. 相似文献
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17.
A. Montanaro 《Journal of Elasticity》1999,57(1):25-53
By extending the procedure of linearization for constrained elastic materials in the papers by Marlow and Chadwick et al., we set up a linearized theory of constrained materials with initial stress (not necessarily based on a nonlinear theory).
The conditions of propagation are characterized for small-displacement waves that may be either of discontinuity type of any
given order or, in the homogeneous case, plane progressive. We see that, just as in the unconstrained case, the laws of propagation
of discontinuity waves are the same as those of progressive waves. Waves are classified as mixed, kinematic, or ghost. Then we prove that the analogues of Truesdell"s two equivalence theorems on wave propagation in finite elasticity hold for
each type of wave.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
A new group of wavelets that have the form of solitary waves and are the solutions of the wave equations for dispersive media is proposed to call elastic wavelets. That this group includes well-known Mexican-hat wavelets is proved. It is proposed to use elastic wavelets to study local features of the profile evolution of a solitary wave in an elastic dispersive medium 相似文献
19.
Reflection and Transmission of Elastic Waves from the Interface of a Fluid-saturated Porous Solid and a Double Porosity Solid 总被引:1,自引:0,他引:1
The reflection and transmission characteristics of an incident plane P1 wave from the interface of a fluid-saturated single porous solid and a fluid-saturated double porosity solid are investigated.
The fluid-saturated porous solid is modeled with the classic Biot’s theory and the double porosity medium is described by
an extended Biot’s theory. In a double-porosity model with dual-permeability there exist three compressional waves and a shear
wave. The effects of the incident angle and frequency on amplitude ratios of the reflected and transmitted waves to the incident
wave are discussed. Two boundary conditions are discussed in detail: (a) Open-pore boundary and (b) Sealed-pore boundary.
Numerical results reveal that the characteristics of the reflection and transmission coefficients to the incident angle and
the frequency are quite different for the two cases of boundary conditions. Properties of the bulk waves existing in the fluid-saturated
porous solid and the double porosity medium are also studied. 相似文献
20.
The present study investigates novelties brought into the classic Biot's theory of propagation of elastic waves in a fluid-saturated porous solid by inclusion of non-Newtonian effects that are important, for example, for hydrocarbons. Based on our previous results (Tsiklauri and Beresnev, 2001), we investigated the propagation of rotational and dilatational elastic waves by calculating their phase velocities and attenuation coefficients as a function of frequency. We found that the replacement of an ordinary Newtonian fluid by a Maxwell fluid in the fluid-saturated porous solid results in: (a) an overall increase of the phase velocities of both the rotational and dilatational waves. With the increase of frequency these quantities tend to a fixed, higher level, as compared to the Newtonian limiting case, which does not change with the decrease of the Deborah number . (b) The overall decrease of the attenuation coefficients of both the rotational and dilatational waves. With the increase of frequency these quantities tend to a progressively lower level, as compared to the Newtonian limiting case, as decreases. (c) Appearance of oscillations in all physical quantities in the deeply non-Newtonian regime. 相似文献