共查询到20条相似文献，搜索用时 15 毫秒
1.
Experimental analysis of the abrasive belt follow-up grinding of Zirconium-4 alloys tubes and pipes 总被引：1，自引：1，他引：0
Abrasive belt grinding experiments of Zr-4 nuclear power tube are carried out by using three different abrasive belts with same size, and the interactive generating mechanism between abrasive and workpiece is analyzed, the main factors of material removal rate and surface roughness of Zr-4 alloys are obtained. With the help of the advanced test facilities, the abrasive grain abrasion and surface topography of the workpiece are observed. The metallographic structure and microhardness of the layer of burnt surface during Zr-4 alloys Grinding are analyzed. Some conclusions are given as follows: the material removal rate and surface roughness are mainly affected by the factors of belt speed, grinding pressure, hardness of the contact wheel and abrasive type, of which, the belt speed is the strongest factor. The adhesion wear of the Zirconium corundum and aluminium oxide abrasive grit is more serious, the most important wear form of silicon carbide is abrasion wear. With the onset of grinding burn, the mechanical properties of Zr-4 alloys are deteriorated obviously. The results provide a theoretical and experimental basis for technical optimization in the grinding of Zr-4 alloys with efficiency and high quality. 相似文献
2.
The stainless steel has excellent properties, but it is difficult-to-grind material. Because belt grinding shows many advantages, grinding experiments with four kinds of abrasive grain on stainless steel are carried out. The correlation mechanism between the abrasive grits and the workpiece, and influence factors on material removal rate are discussed. A scanning electric microscope was used to investigate the surface micro-shape characteristics of abrasive grit and workface. The material removal mechanism and the wearing types of abrasive belt are also analyzed. 相似文献
3.
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
4.
By using servo control shear loading system, specimens with non-coplanar rock-like intermittent joints were tested by the way of forward and reverse direct shear, rupture mechanism and shearing law for rock bridge with non-coplanar intermittent joints were studied under direct shear. The experimental studies showed that five apparent stages are presented in the process of rock bridge rupture under direct shear, which are linear elastic stage, initiation and extension of crack, fracture and transfixion of rock bridge, climbing and occlusion of shear plane and residual friction. Rock bridge presented profile fracture plane under forward direct shear. While under reverse direct shear, band form fracture plane is showed which penetrated along with the direction of forward shear, and the shear strength of initiation and peak shear strength under reverse direct shear are bigger than that under forward shear. Crack angle, normal stress and lap proportion among adjacent joint are the main factors that influence the initiation strength and peak shear strength. The FLAC 3D simulation for the process of non-coplanar intermittent joints rock bridge rupture and formation of shear rupture surface under forward and reverse direct shear was conducted. The results of numerical simulation agreed well with those of experiment. The simulation results revealed tension crack failure of non-coplanar intermittent joints rock bridge and shear yielding mechanism of fracture plane. 相似文献
5.
Experimental analysis of abrasive belt grinding of glass fiber reinforced plastic composite material
Abrasive belt grinding experiments of glass fiber reinforced plastics composite material are carried out by using three different abrasive belts with different sizes,and the interaction principle between the abrasive and the workpiece is analyzed.The main factors of material removal rate and belt life of glass fiber reinforced plastics composite material are obtained through a large number of tests and test data.The extent and the main reason of belt plug are analyzed through the professional image analysis software (Image Pro Plus) for the first time.The results show that in the process of abrasive belt grinding,the material removal rate are affected by the factors for grinding pressure,belt speed,abrasive type and size,and the ceramic abrasive belt has the highest removal rate.The main factor for belt plug extent is grinding pressure.The most important wear form of abrasive belt is blunt,and the accumulation abrasive belt has the longest life,followed by ceramic abrasive belt. 相似文献
6.
By using a simple shear apparatus that is developed from RMT-150B,a series of simple shear tests of interface between saturated sand and structure under high normal stress were carried out to study constitutive law and shearing stiffness of interface to provide some theoretical evidences for design and calculation of projects concerned with mechanical problem of interface.In test,sand was consolidated in upper shearing box firstly,then,shear was started and testing data was recorded under high and constant normal stress.During the process,sand can deform relatively freely.It is shown that the relation curve between shear stress and shear displacement under high normal stress in simple shear tests is different from that in direct shear tests,and the complete shearing deformation process of interface under high stress can be described as a nonlinear elastic-perfect plastic form;Weibull distribution with three parameters can overcome the mathematical deficiencies of hyperbola in NEPP.The new model which is established by substituting Weibull distribution for the hyperbola of NEPP better agrees with the testing data.The regressive results of the initial shearing stiffness demonstrate that the linear function is slightly better than power function to express the relation between the initial shearing stiffness and normal stress.Based on the new interface model,the formula of tangential shearing stiffness is proposed,meantime,the change trend of tangential shearing stiffness of the new model is compared with that of NEPP. 相似文献
7.
In order to ensure that the T shaped steel reinforced concrete short-pier shear wall ductile shear failure occurs, the failure mechanism on the basis of experimental research, using ANSYS finite element analysis software to simulate the failure mode. In the process of analysis considered the influence factors of horizontal steel reinforcement ratio, concrete strength, axial compression ratio and the content of steel. The results show: the level of reinforced volume reinforcement ratio, concrete strength and the content of steel can obviously change the the bearing capacity and ductility of components. 相似文献
8.
Liang Xichang 《保鲜与加工》1989,(1):1-7
The paper describes a new theory and methods for designing hyperbola, degenerate circles, involute and roulette curves which have been applied in grinding convex involute gears, cutting special profiles on a gear shaper, grinding the race-way of ball thrust bearings, form grinding and grinding cyclo-cycloidal gears with an abrasive belt. All these applications have been used in industruy with considerable benefits.
The curves are produced by different combinations of straight line and circle motions, Given the curve parameters of the workpieces to be machined, the best approximate curve can be obtained from a computer program designed for this purpose. 相似文献
9.
Based on the principle of interactive analysis,the deformation equation of hybrid structure which contains rigid character value is established using the analysis of the frame - shear wall structure for reference, considering the rigid zone between concrete beam and concrete - tube, the shear deformation of concrete - tube, axial deformation of steel frames and semi - rigid connection between steel columns and concrete beams. Assuming the hybrid structure to be a continuous elastic structure with infinite degree of freedom, a free vibration equation has been built and the formula for calculating free vibration period has been deduced. The influences of various parameters to the coefficient of free vibration period relating to rigid character value are discussed according to some diagrams. It is shown that the rigid zone can lessen the free vibration period but the shear deformation of concrete - tube, axial deformation of steel frames, and the semi -rigid connection between steel columns and concrete beams can enhance the free vibration period. 相似文献
10.
In this paper the test results of mixed mode fracture of three kinds of brittle rock under two kinds of stress paths are reported. The fracture mechanism and failure patterns of brittle lock under different stress paths are discussed. Theory analysis and test results show that the Compression- Shear fracture criterion of brittle rock can be expressed: 相似文献
11.
Wang Cheng 《保鲜与加工》1999,(2):66-69
The concrete is a typical brittle material.The fracture and propagating failure of the micro-crack in loaded concrete are very important problem in civil engineering.In this paper,from the equilibrium differential equations and failure criterion,the elastic-brittle static fracture analysis of the plane stress micro-crack in concrete loaded by stretching stresses was done near crack line.The relations between the stretching stresses and the length of brittle fracture zone on the crack line were obtained. 相似文献
12.
研究了采用超声波辅助提取技术对黑加仑多糖进行提取,并对工艺条件进行优化。结果表明,超声波辅助提取黑加仑多糖的最佳工艺参数为:超声波功率140 W,超声波处理时间为30 min,恒温水浴浸提时间为1.5 h,料液比为0.5,黑加仑粗多糖得率1.8g/100 mL。通过正交试验进一步优化提取工艺条件,确定影响提取率的主次因素分别为料液比、超声波功率、超声波时间、水浴浸提时间。 相似文献
13.
Mechanical injuries are the main cause of damage (such as bruising) and loss of quality of fruit and vegetables, occurring mainly from mechanical forces during compression, vibration and impact loads. Apples and potatoes are susceptible to external and internal pressures, which causes bruising and fracture in soft tissues. The study of turgor pressure and the compressive stiffness of apple and potato tissues is essential to understand their fracture strength against external and internal pressures. In the present study, a generalized form of a strain energy function is proposed, and a relation between turgor pressure and stretch ratio is developed by considering its appropriate form. It is considered that the tissues are isotropic, incompressible, homogeneous, and show hyperelastic behavior. The Levenberg–Marquardt algorithm was used for regression analysis to calibrate the material constants by correlating predicted and experimental values of turgor pressure and stretch ratio for apple and potato tissues. A good fit of the developed relation to experimental data was obtained with the coefficients of determination of 98.02% for apple and 98.0% for potato. 相似文献
14.
Wang Cheng 《保鲜与加工》1997,(2):31-35
In this paper the elastoplastic stress fields near joint line in rockmass loaded by compress- shear are analyesd by the line field method in fracture mechanics with Mokr- Coulomb criterion. Through the matching conditions of the elastoplastic fields on their boundary, the relations between the length of plastic zone on the joint line and the compress- shear loads are found, and the fracture criterion of the discrete joint is also obtained 相似文献
15.
采用乙酸作为提取溶剂,结合超声波辅助提取,研究了不同溶剂浓度、超声辅助提取时间、提取温度、提取功率和料液比各因素对苹果渣中的多酚类化合物提取效果的影响。确定提取苹果渣中多酚的最佳工艺条件为:以体积分数40%乙酸为提取溶剂,超声处理时间70 min,提取温度30℃,超声功率105 W,料液比1∶50,且各因素之间的主要次序为:料液比>提取时间>提取温度>超声功率。 相似文献
16.
Based on the theory of solid and liquid coupling wave mechanics, the micro-dynamical characteristics caused by the transport of ultrasonic in porous media at near wellbore zone, including the elastic deformation of rock, the elastic crossflow of pore fluid and frame solid, and fluid squirt-flow produced by pore elastic deformation, are analyzed. Analysis of kinetics of peristaltic difference of porosity radius in porous media is presented. The characteristics of the removal of inorganic scale particle in porous media by using ultrasonic technology are also studied. Besides, by applying high power ultrasonic technology, the acoustic energy gathering in porous media at near wellbore zone leading to fracture of part rocks is illustrated. According to these analyses, the micro-dynamical mechanisms, such as inorganic scale fragmentation, ultrasonic cavitations, ultrasonic friction, ultrasonic peristaltic transport and ultrasonic fracture-making, occurred in inorganic scale plugging removal by high power ultrasonic technology are proposed. 相似文献
17.
超声波辅助萃取毛葱油工艺的响应面法优化 总被引：1，自引：0，他引：1
采用有机溶剂为载体对毛葱油进行超声波辅助萃取。在单因素和响应面优化设计试验的基础上,确定了最佳提取工艺条件:以二氯甲烷为萃取剂,料液比1:3,超声功率209W,超声时间37 min,超声温度31℃,在此条件下,毛葱油得率可达4.45g/kg。得到的毛葱油为棕色黏稠液体。 相似文献
18.
According to the characteristics of plane strain problem of elastic and plastic mechanics, the bi parametric expressions were derived for stress components satisfying the generalized Hoek Brown failure criterion. Being substituted into the static equilibrium partial differential equations, a group of first order hyperbolic pseudo linear differential equation partial differential equations was obtained. Utilizing the determinant method and proper variable transformation, the characteristic direction and the differential relation equation for the stress partial differential equations were acquired. The characteristic direction indicted that in plastic zone obliquely intersecting conjugate shear slip surfaces formed two families of non orthogonal slip lines, in which conjugate angle varied with the limit stress state and the material physical properties of Hoek Brown rock mass. Since the principal direction of the maximum principal stress was circumferential in perfectly elasto plastic surrounding rock of the plastic zone around a circular opening suffering the symmetric initial stress field, the angle between the tangential direction of slip line with the principal direction of the maximum principal stress was the function of the minimum principal stress(i.e. the radial stress). Combined with the analytical solution, the polar coordinate differential equation was derived and furthermore, the polar coordinate curve equation for the slip line was obtained. 相似文献
19.
本文以商洛黄芩为实验材料,采用超声辅助乙醇提取黄芩中汉黄芩素,研究超声时间、超声提取温度、超声功率、料液比和乙醇体积分数等因素对汉黄芩素提取率的影响,在单因素试验的基础上,设计3因素3水平响应面试验,分析各因素的显著性和交互作用,确定的优化工艺为：在超声功率140W、料液比1:20、乙醇体积分数60%前提下,黄芩汉黄芩素提取率为0.526%。将汉黄芩素提取液与1.5%壳聚糖、1%柠檬酸进行复配,制备复合保鲜液,以感官指标、pH值、菌落总数为检测指标,模拟易导致新鲜草莓变质的温度和湿度进行保藏试验,通过对草莓品质的评价说明不同浓度黄芩汉黄芩素复合保鲜液的保鲜效果,结果表明：0.20%复合保鲜液即可以保藏新鲜草莓3d,0.40%复合保鲜液能够有效地保藏新鲜草莓5d。由于试验模拟草莓极易腐败变质的温度,可以预测室温下草莓贮藏期更长。本研究结果可作为商洛地区黄芩中汉黄芩素应用的技术参考。 相似文献
20.
Yan YongTang Zilin 《保鲜与加工》1993,(6):138-143
This article summeried the methtods in finish machining of hardened gear and mainly introduced the development of the form grinding technique in grinding wheel dressing and grinding technology. The technique, which makes use of CBN tools, of hardened gear finish machining is also briefed. 相似文献