共查询到18条相似文献，搜索用时 187 毫秒
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小麦堆体变模量的测定与实验研究 总被引：2，自引：0，他引：2
利用应变控制式三轴仪对小麦的体积压缩和体变模量进行了实验测定,并探讨了围压和水分对体变模量的影响。结果表明:小麦堆的体积随着围压的增大而减小;小麦堆(水分为13.7%、16.4%、18%)的体变模量随着围压(5 kPa～30 kPa)的增大而增大,它们的体变模量的范围分别为173.5 kPa～259.3 kPa、164 kPa～240 kPa、151 kPa～229.4kPa;小麦堆体变模量随着水分的增大而减小,当小麦堆围压为30 kPa,水分为13.7%～18%时,它的体变模量变化范围为223.5 kPa～270 kPa。 相似文献
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使用TSZ-6A型应变控制式三轴仪对不同围压(8kPa~200kPa)、不同含水率(9.8%、11%、13.5%、14.8%、15.8%w.b.)的黑龙江省大豆堆的体积变化和体变模量进行了测定,分析了围压与含水率对大豆堆体变模量的影响。体变模量随着围压(8kPa~200kPa)的增大而增大,大豆实验结果表明:对含水率为9.8%w.b~15.8%w.b、围压为8kPa~200kPa的大豆堆,其体变模量范围为227.94kPa~610.58kPa。相同含水率的大豆堆的体变模量随着围压(8kPa~200kPa)的增大而增大;同一围压下,大豆堆体变模量随着含水率(9.8%w.b~15.8%w.b)的增大而减小。 相似文献
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利用LHT-1型粮食回弹模量测定仪对玉米堆在不同条件（预压力,水分）下的无侧向膨胀回弹模量进行了实验测定,分析了不同预压力（0、100kPa、200kPa）、不同水分（13.89%、15.12%、17.71%、18.74%）对玉米堆回弹模量的影响;弹塑性形变之比与预压力的关系以及每次加卸载时塑性形变的变化规律。实验结果表明：同一水分下,玉米堆的回弹模量随着预压力的增大而增大;同一预压力下,随着水分增大,玉米堆的回弹模量减小;第五圈的弹塑性形变之比随预压力的增大而减小;每次加卸载后塑性形变随加载次数的增加而减小。 相似文献
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稻谷堆弹性模量的实验测定与研究 总被引：3，自引：0，他引：3
利用TSZ-6A型应变控制式三轴仪进行三轴实验,测定围压分别为50 kPa、100 kPa、150 kPa、200 kPa时,稻谷堆（水分为11.89%w.b,13.55%w.b,15.73%w.b,17.62%w.b）的弹性模量,同时研究围压和水分与稻谷堆弹性模量的关系。实验结果表明：对于水分范围为11.89%~17.62%w.b的稻谷堆,在围压为50 kPa~200kPa的范围内,其弹性模量范围为8.69 MPa~37.07 MPa。根据围压与稻谷堆弹性模量的关系可以拟合得到方程：y=Ax＋B,其中,A、B为与水分有关的参数。在相同水分条件下,稻谷堆的弹性模量随着围压的增大而增大;在相同围压条件下,稻谷堆的弹性模量与水分没有显著的相关性。 相似文献
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稻谷仓壁材料摩擦系数的实验研究 总被引：1，自引：0，他引：1
利用土工合成材料综合测定仪测定了不同法向压应力（25 kPa、50 kPa、100kPa、150 kPa、200 kPa）下稻谷（水分含量为13.55%、15.14%、17.00%、19.19%w.b）与不同仓壁材料（不锈钢板、混凝土板、木板）的摩擦系数。结果表明：稻谷与不锈钢板摩擦系数较小,与混凝土板和木板的摩擦系数较大;随着法向压应力的增大,稻谷与各仓壁材料的摩擦系数均呈不同幅度的减小;随着水分的增大,稻谷与各仓壁材料的摩擦系数增大。根据实验结果,可拟合出摩擦系数与法向压应力、水分含量的关系方程。 相似文献
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使用TSZ-6A型应变控制式三轴仪对不同围压(50 kPa、100 kPa、150 kPa、200 kPa)、不同含水率(9.8％、12.3％、15.8％、17.2％w.b)的大豆堆的弹性模量进行了测定,并分析了围压与含水率对大豆弹性模量的影响.实验结果表明:对于含水率范围为9.8％～17.2％ w.b的大豆堆,在围压为50 kPa～200 kPa的范围内,其弹性模量范围为3.07 MPa～28.80 MPa,在相同含水率条件下,大豆堆的弹性模量随着围压的增大而增大；在相同围压条件下,大豆堆的弹性模量随着含水率的增加而减小. 相似文献
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利用土工合成材料综合测定仪测定了江苏盐城产糙米与不锈钢板、混凝土板、木板三种不同固体界面的摩擦系数。实验结果表明:随着剪切速率(1.33mm/min、2.67mm/min、4.33mm/min、5.20mm/min)的增大,糙米与固体界面的摩擦系数逐渐减小;随着法向压应力(25kPa、50kPa、75kPa、100kPa)的增加,糙米与固体界面的摩擦系数逐渐减小;随着糙米含水率(15.32%w.b、16.24%w.b、17.54%w.b、18.46%w.b)的增大,糙米与固体界面的摩擦系数逐渐增大。根据实验结果,分别拟合出糙米和不锈钢板、混凝土板、木板三种不同固体界面摩擦系数与剪切速率、法向压应力、含水率的关系方程。 相似文献
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页岩烧结保温砌块砌体基本力学性能试验研究 总被引：1，自引：0，他引：1
通过对页岩烧结保温砌块砌体轴心抗压、沿通缝抗剪、剪压复合抗剪性能试验研究,分析其破坏特征和破坏机理。试验结果表明:页岩烧结保温砌块砌体受压破坏时,在竖向灰缝附近形成主裂缝,接近极限荷载时砌体出现表皮剥落现象;沿通缝抗剪破坏模式主要为单剪破坏,脆性明显;剪压破坏有剪磨、剪压和斜压3种类型;实测轴心抗压强度平均值高于规范值,沿通缝抗剪强度、复合抗剪强度平均值低于计算值,并分别给出砌体轴心抗压强度平均值、抗剪、剪压复合受力抗剪强度平均值建议公式;剪压复合抗剪强度随着压应力的增大而增大;建立了页岩烧结保温砌块砌体受压应力应变关系表达式;给出该类砌块的弹性模量和泊松比的建议值。 相似文献
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Closed-form Analytical Solution for Beam on Elastic Foundation with Different Tension and Compression Modulus 总被引：1，自引：0，他引：1
On the basis of the theory of different modulus, the closed-form analytical solution for beams on elastic foundations with different modulus has been derived. A comparison is made between the results of the analytical solution and those calculated from the classic mechanic theories, in which the tension modulus are equal to the compression modulus. It is shown from the numerical results that the ratio of compressive modulus to tensile modulus will greatly affect the elastic characteristic values,internal forces and flexibilities. The present theory satisfies the mechanical behavior of materials. The amount of materials can be economized through rational design by using the elastic theory of different modulus. 相似文献
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In order to know the behavior of local nonuniform compression of fired shale perforated brick masonry with rectangular holes,the experimental study of 18 specimens with and without restriction at the end of beam under local compression was carried out.The failure modes and bearing mechanisms of specimens were researched and analyzed,the integrity coefficient of local compression stress figure was deduced,at last,the theoretical and testing values of local compression bearing capacity were compared and analyzed.The results indicate that the bearing performance at the end of wall section under local compression behaves better than that on the fringe,the vertical cracks throughout the specimen on the fringe caused by local nonuniform pressure weaken the advantageous function of 'unloading by the interior arch',the effective supporting length calculated according to code for design masonry structure is partial to safety.These results and suggestions can be used in the design of bearing perforated brick masonry for reference. 相似文献
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The distribution of the axial stress and shear stress on the anchorage segment and the formulation for calculating the anchorage length were derived based on the stress analysis of the anchorage segment of compression anchor. And the effects of parameters, including the elastic modulus, poisson ratio, cohesion, and internal fiction angle of rock mass, on the anchorage length were studied. The results show that the anchorage length decreases with the increase of the elastic modulus, cohesion and internal friction angle of rock mass; and the anchorage length increases linearly but limited with increasing of poisson ratio of rock mass; and it also increases with increasing load. 相似文献
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红锥3向弹性常数研究 总被引：1，自引：0，他引：1
通过实验获得红锥的3向（纵向、弦向、径向）弹性模量和3向泊松比,以掌握红锥的弹性形变特性,为进一步研究红锥的物理力学性质及为木结构设计提供依据。以电阻应变片为变形传感器,采用单轴压缩并通过电阻应变仪进行应变测量,由材料力学方法获得红锥的3向弹性模量和3向泊松比。实验结果表明,红锥在3个主方向的弹性模量分别为EL=9352 MPa、ET=573 MPa、ER=1727 MPa,3个主方向上的泊松比分别为μLT=0.616、μLR=0.457、μTL=0.038,μTR=0.282、μRT=0.785、μRL=0.067。红锥的弹性模量纵向（L向）最大,径向（R向）次之,弦向（T向）最小,泊松比则弦向最大,径向次之,纵向最小。 相似文献
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Experimental results of the basic mechanical properties and failure mode performed on rock salt demonstrate that rock salt is a typical and peculiar soft rock , whose" Young' s modulus/strength(E/S)"ratio is extremely small,and whose failure follows the deformation failure criterion. With these results,this paper develops a theoretic breakdown criterion of hydraulic fracturing in rock salt,which is based on the greatest tension strain failure theory and includes the vertical stress effects. It has been suggested that the critical tension strain should be determined from uniaxial compression tests. This theoretic criterion exceedingly agrees with experimental results and is applicable for every soft rock with small E/S ratio under various stresses. 相似文献
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The bending capacity tests on ten simple supported beams were conducted to investigate the damage characteristics, prestress increment, beading capacity and displacement ductility of unbounded prestressed concrete beams with HRBF500 steel bars. The results show that the HRBF500 steel bars has yielded before the limit state. The concrete in compression zone crushes upon the broken of the beams, which shows a sudden damage mode. The measured ultimate stress increments of unbounded tendons are in linear relationship with the comprehensive reinforcement ratio index, while the values of the ultimate stress increments are obviously higher than those values specified in the code GB50010-2010, and the average ratio of predicted values to testing values is about 0.35. The mid span deflection upon yielding of the beams is large, while the displacement ductility is bad and the average value of the displacement ductility ratio is 1.67. The displacement ductility ratio decreases with the increases of the comprehensive reinforcement ratio index. Based on the experimental results, the proposed calculation formula of ultimate stress increments of unbounded tendons was established, and it is in good agreement with the experimental results when the testing value is less than 450 MPa. 相似文献
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The climate has a great impact on highway bridge rubber bearings than on building rubber bearings. In order to study the change of the mechanical properties during the life of the plain chloroprene rubber bearings of highway bridge under freeze-thaw cycle condition, the plain chloroprene rubber bearings were processed 25, 50, 75, 100 times by freeze-thaw cycle in the standard freeze-thaw chamber, then the axial compression tests were carried. The changes of the performance indicators in the bearing capacity , the ultimate compressive strength, vertical stiffness, elastic modulus under different freeze-thaw cycles were analyzed comparatively. The results show that the plain chloroprene rubber bearings are more prone to brittle failure after the freeze-thaw cycle, and the failure phenomena of steel plate exposing or cracks is more serious than the phenomena of the standard specimen. With the increase of the number of freeze-thaw cycle, the ultimate bearing capacity, ultimate compressive strength and compressive elastic modulus of the plain chloroprene rubber bearings decrease. The attenuation formula and decay curve in 50 years of ultimate compressive strength and elastic modulus of compression are analyzed by least square method, the trends of change are both in line with the exponential function. The mechanical properties of plain chloroprene rubber bearings of highway bridge significantly decreased under freeze-thaw cycle condition. therefore, the temperature ranges of plain chloroprene rubber bearings of highway bridge should be strictly controlled, and some suggestions, such as increasing its minimum applicable temperature, usng the natural rubber bearings as much as possible in cold regions, have been given. 相似文献