破坏应力

In order to study the reasons and preventive measures of dynamic disasters such as shock bump and the destroy of rock mass in mining engineering resulted from the outburst of mash gas and coal during mining,stress-relieving measurement and temperature and confining pressure calibration were made with improved CSIRO cells at 4 measurement points in Datong mining area .

为了研究大同矿区在煤炭开采过程中煤和瓦斯突出形成的冲击地压、采矿工程围岩破坏等动力灾害的形成原因及其防治对策，采用改进型CSIRO空心包体应变计，对大同矿区进行了四个测点的应力解除测量实验以及室内温度标定和围压率定实验。

It is shown that the contact interaction enables bottom drillstring to whirl backward, and then an alternate bending stress with higher frequency is produced. So the drillstring fatigue failure could be accelerated. At the same time, a quite strong wallop force of high frequency is produced on the contacting point, and the contacting zone is next to the screw coupling of drill collars. It will easily result in the failure of screw couplings. The research results provide theoretical basis for the prevention of drillstring failure.

研究表明，下部钻柱与井壁的碰摩作用使下部钻柱反向涡动，产生高频的交变弯曲应力，会加速下部钻柱疲劳破坏；下部钻柱与井壁接触点处存在较大的高频冲击力，并且接触区域靠近钻铤螺纹联结处，更容易诱发螺纹联结处失效，该研究成果可为预防钻柱失效提供理论依据。

In order to study basic roof's destruction movement that affects working face in horizontal section top coal caving in mining steep seams, this paper analyses tension of roof using elastic and thin board theory and concludes criterion of roof destruction based on long and narrow thin board.

摘要为研究急斜煤层水平分段放顶煤开采过程中基本顶破坏活动对工作面的影响，根据急斜煤层基本顶具有倾斜狭长板的特点，运用弹性薄板理论对基本顶岩层进行了拉应力分析，得出了顶板破断的判别准则，建立了基本顶初次破断后形成的&铰接结构&的力学模型。

According to field investigations and the results obtained by in-situ stress and strain measurements, some conclusions about the phenomena and mechanism of the rock pressure were drawn, and it was found that

根据现场调查，以及应力和位移测量的结果，得出了地压活动发生机制的一般规律，并指出：产生大面积地压活动最主要的原因是采空区中矿柱的破坏和倒塌。

The relationships between strain and stress of several kinds of high strength fibers, such as Kevlar, Twaron and Dyneema were obtained, and the dependence of mechanical properties of fibers on the strain rate was gotten and explained from the microstructures and deformation mechanism of fibers. Then, the damage and failures of plates with the reinforcement of fibers under high velocity impacting were studied experimentally. Based on experimental results, a set of equations was presented to depicted the deceleration of penetrator. The dynamic response of fiber cluster and sandwich were simulated successfully with a new algorithm and code, which was developped by our group. The coupling effect of stress wave and thermal conduction could be considered with acceptable accuracy and CPU time.

其中，获得了以芳纶纤维为代表的7种纤维的动态应力应变关系，从材料微观机制解释了纤维束的应变率相关特征；得到了板材在高速冲击下的能量吸收机理，以及影响能量吸收机制转变的主要因素；发展了一种新型的原位光学测试技术，以之可以测量试件在冲击加载下的变形场及其演化，该技术除了在本项目应用外，还可以对剪切带的萌生演化、孔洞动态扩张规律进行较好的观察，以弥补相关研究中实验证据的缺乏；发展了含热传导的冲击动力学有限元程序，在侵彻、绝热剪切带、脉冲激光诱导结构破坏等问题的分析中得到了较好的应用。

On the basis of the shear-lag theory,this paper studies the microstress redistributions induced by the interaction of failure of 90° layers and the breakage of some fibers in 0° layer in cross-ply laminates under tension in 0° direction.

摘 要 基于剪滞理论，研究了在0°方向承受拉伸的复合材料正交叠层板由90°层的破坏及0°层中部分纤维断裂相互作用所导致的细观应力重新分布。

The stress and strain redistributions were calculated when the carbon ply fractured and delamination occured.

计算了当试样内碳纤维断裂及出现脱层破坏时的应力，应变的重新分布规律。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。