根据脉冲放电对含圆柱形非金属夹杂构件所引起的温度场,将其分解为轴对称温度场和非轴对称温度场两部分,采用热弹性位移势及叠加原理,在给定的边界条件下,分别求解两类温度场所引起的热应力场。以16Mn构件强化为例求解夹杂边界处热应力分布发现,在该区域,无论径向、周向应力均为压应力,而且远超出材料的屈服强度;在温度和应力耦合作用下,将极大影响夹杂附近的组织性能及应力状态。进一步研究沿径向路径的热应力变化发现,脉冲放电引起的热应力仅对含夹杂区域的组织性能及应力状态影响较大,而对无夹杂区域并没有太大影响,因此,该技术可应用于在线构件的强化。

According to the temperature of pulse discharge in metal components with cylindrical non‐metallic inclusion ,the tem‐perature field can be decomposed into the axial symmetry temperature field and asymmetric temperature field .The stress field is solved through potential of the thermal displacement and superposition principle under the boundary condition of assignment .And taking 16Mn components as example ,it is discovered that both radial and circumferential stresses around the inclusion are com‐pressive stress which far exceeds the yield strength .Therefore under the coupling effect of temperature and stress ,the micro‐structure and properties nearby the inclusion will be affected significantly .Furthermore ,the Mises stress is more significant near‐by the inclusion than anywhere by discussing the thermal stress along the radial direction .Therefore ,this technology has less effects on the region without inclusion and can be used on online strengthening .

分析了高地应力条件下静水压力场中圆形隧洞钻爆开挖时开挖边界上初始应力场动态卸荷效应并计算了其围岩弹性位移场及应力场，并与相应准静力卸荷情况进行对比。将围岩动态位移场分解成准静力位移和动力位移两部分进行计算求解，并进行叠加。主要考虑动态卸荷条件下圆形洞室围岩的径向弹性位移场的分布，卸荷时间越短，对围岩扰动越大；卸荷后，围岩的弹性位移场形成波动位移，产生震动响应，与准静力结果相比，动力响应位移结果要大于准静力位移。

The dynamic unloading effect of initial stress in hy-drostatic field in excavation process of circular tunnel by blasting un-der high geostress condition was studied and the elastic displacement field of surrounding rock was calculated.Compared with corresponding quasi-static unloading.Dynamic displacement field of surrounding rock is decomposed into the quasi static displacement and the dynamic dis-placement two parts to calculate,and stack.The shorter the unloading time is,the bigger disturbance to surrounding rock.After unloading,e-lastic displacement field of surrounding rock emerged wave displace-ment,dynamic response of displacement is bigger than the quasi static displacement.

位移图成像是超声弹性成像算法中一个非常关键的步骤。目前对于弹性成像的研究大多关注在位移图的成像过程和成像速度，而对于位移图中常出现的奇异点等噪点的修复，一直提及较少。简单介绍弹性成像的基本原理，并重点针对位移图中出现的奇异点提出一种修正算法。该算法能有效地修复位移图中的奇异点，具有高效和针对性强的特点。作为一种后处理算法，该算法可以运用于不同的弹性成像算法中，具有较高的使用价值。

Displacement diagram is a key step in ultrasonic elastography imaging algorithm. Currently most of the research attention elastography imaging process in the displacement map and imaging speed, and for the displacement map singularities often occur, such as the noise of repair, has been mentioned less. Introduces the basic principles of elastography and focuses on displacement map singularities appear-ance, proposes a correction algorithm. The algorithm can effectively repair the singular point displacement map, with efficient and targeted characteristics. And as a post-processing algorithm, it can be applied to different elastography imaging algorithm, has a high value.

基于弹性地基Pasternak双参数模型,利用分数阶微分得到黏弹性地基双参数模型,并在此基础上建立采用分数阶微分Kelvin模型的双参数黏弹性地基上弹性和黏弹性矩形板在动荷载作用下的动力方程;利用Galerkin方法和分段处理的数值计算方法求解四边简支的弹性和黏弹性地基板的动力方程,通过自由振动算例验证该求解方法的正确性;并分析冲击动荷载作用下分数阶微分Kelvin模型的分数阶、粘滞系数、水平剪切系数和模量参数对位移响应的影响。结果表明:分数阶微分黏弹性模型可以描述不同黏弹性材料的力学行为;分数阶取值0.5前后,矩形板位移响应值出现了不同的衰减发展形态;粘滞系数、水平剪切系数和模量系数取值越大,位移响应衰减速度越快。

Based on a two-parameter Pasternak model of elastic foundation,a two-parameter model of viscoelastic foundation was derived by using fractional derivatives.The dynamic equations of elastic and viscoelastic rectangular plates on a two-parameter viscoelastic foundation with the fractional Kelvin model under dynamic loads were established.The dynamic equations of elastic and viscoelastic rectangular plates with four-edge simply supported were solved with Galerkin method and the segmented numerical method,the correctness of the solutions was verified with examples of free vibration. The influences of fractional order,viscosity parameter,horizontal shear coefficient and modulus of the fractional Kelvin model under an impact load on the displacement responses of the plates were analyzed.The results showed that the fractional derivative viscoelastic model can describe the mechanical behavior of different viscoelastic materials;the displacement responses of the rectangular plates have differen

求解弹性力学问题的应力时,如果采用常规的位移有限元法,需要先求得单元的结点位移,再经过求导运算来得到。为了解决这种求解方式引起的应力精度下降的问题,提出弹性力学问题的一阶多变量形式,使得应力与位移精度同阶,并推导弱形式。采用有限元方法,对弹性力学问题给出一阶解法的数值算例,并且将一阶解法的结果与常规位移有限元法的解进行比较。数值计算的结果表明:一阶解法有效地提高了应力的计算精度,并且应力的误差与结点位移的误差具有相同的收敛阶,从而验证所提方法的有效性,为提高有限元法的应力精度提供了新的思路。

In the conventional displacement finite element methods, the stresses are obtained from a differential operation after the nodal displacements are determined.In order to improve the accuracy of the stress, a first-order multivariable form was proposed to make sure that the order of stresses and displacements should be equal, and the weak form was then derived.Using the finite element method, a two-dimensional elastic problem was solved by first-order method, and the first-order solutions and the solutions of the conventional displacement finite element method were compared.The numerical results showed that the first-order solution effectively improved the accuracy of the stress while the displacement errors and the stress errors had the same convergence order, which verified the effectiveness of the method and provided a new idea of improving the accuracy for the finite element method.