forming process planning and technology realization of the monoblock break beam frame

In order to meet the performance demands of train lorry, a die forging drawing method based on structure features analysis was proposed to form the L A break beam frame. The finite element method was used to simulate a series of die forging processes and the drawing processes with different parameters. The optimum cross section shape of the performing die was obtained from these simulation results. It is found that local back flow of the metal is the primary cause of necking defects in drawing. Furthermore, the best drawing speed is determined to be from 87 mm/s to 96 mm/s. The results of trial manufacturing and product detection indicate that employing a die forging drawing process to form the monobloc break beam frame is feasible.     

Research of Structure Optimization Design for Ten Mile River Landscape Bridge

Guiyang Huaxi district landscape bridge is seven miles the beach driving bearing type reinforced concrete box arch bridge, the design process of conventional arch bridge solutions with less thrust arch bridge to carry on the comparison, the combination of special terrain, geological conditions, finally chose the foundation excavation is small, economical, reasonable structure, less thrust of arch bridge using edge inclined rod and bearing platform consolidation, forming the free cantilever end method better solve the horizontal thrust at arch feet larger, by establishing the structure finite element model, analyzes the static force performance, the results show that the thrust of arch stress performance good, less economically feasible, beautiful appearance, and the scenic spot environment more harmonious.     

Simulation and Experiment of the Forging Process of Railway Lorry Bomsster

Bomsster is a key load-bearing part of railway lorry bogie.Because of its inherent defects casting-steel bomsster could not meet the demands of the heavy load,acceleration and security for lorry.So forging process is proposed to form it.The forming performance of forging-steel bomsster is analyzed.A forging technology is presented which realizes two forging-steel bomsster parts formed in one die.With the plastic forming simulation software DEFORM-3D,the simulation and optimization of the forming process of forging bomsster has been taken based on 3D rigid visco-plastic FEM theory.Optimized scheme has been used to direct the pilot product.The results of product's testing and application suggest that the new forging technology is feasible and the performance of the product is credibility and stabilization.The factory has realized large scale production of a series of forging-steel bomsster.Remarkable benefits of both economy and society have been achieved.     

Study on Simulation of Contact Friction Condition of Continously Variable Transmission

As metal Belt CVT(Continuously Variable Trans mission) acts as a kind of friction transmission, friction coefficient is a key parameter of CVT. The friction characters of CVTF(Continuously Variable Transmission Fluid) are mainly determined by fluid and contact state. The contact between belt and pulley can be regarded as a kind of contact between cylinder and cone. As their contact line is short, the curvature change of pulley along the contact line can be neglected. Then the contact problem of belt and pulley was reasonably simplified as a contact between cylinder and cylinder. Under the state of equivalent maximum stress, the contact friction condition of metal belt and pulley was simulated by the contact of ring and block in Timken Friction Test Machine.     

直剪法用于糙米内摩擦角的测定与研究

利用土工合成材料综合测定仪（直剪仪）,以水分含量14.57%的糙米为样品,测定了在不同的法向压应力、不同的剪切速率下糙米的剪切应力并计算出内摩擦角。实验结果表明：糙米的剪切应力随着法向压应力（25kPa～100kPa）的增大而增大;剪切速率（1.33mm/min～2.67mm/min）较低时糙米的内摩擦角随着法向压应力的增大而减小;随着剪切速率（1.33mm/min～5.20mm/min）的增大,糙米的内摩擦角减小。     

Effective Unloading Area between Cantilever Piles

The formation mechanism of the arching effect between cantilever piles is studied according to their stress characteristics. The soil arch is classified into three types based on its position in a space coordinate system, namely, a horizontal arch, a vertical arch and a free face arch. The master factor for distribution of unloading area between piles is the horizontal arch effect. The range of effective unloading area is defined. Based on the failure pattern of soil arches and the relationship between soil strength theory and the static equilibrium principle of soil arches, a calculation model is established by considering the presence of geostatic stress and sliding thrust force. The relation between soil strength and critical height is studied by variation of cohesion and friction angle. In addition, the impact of canonical distributions of the earth pressure to the vector height of unloading area is also discussed. Finally, the calculation model is verified by an example from real engineering work.     

DEVELOPMENT AND TEST ON ROLLING CONE ENVELOPING HOURGLASS WORM PAIR

The rolling cone enveloping hourglass worm pair has been successfully developed, in which there is almost only rolling friction between the meshing tooth surfaces, and both the worm and wormwheel have hard surfaces. Such a new type of hourglass worm pair is particularly-favorable for power transmission. This paper presents the design. manufacting and testing of this worm pair.     

结构参数对水润滑橡胶合金轴承摩擦噪声的影响分析

为了研究水润滑橡胶合金轴承结构参数对其低速重载工况下摩擦噪声的影响,使用复模态分析方法建立了水润滑橡胶合金轴承系统仿真模型,采用专业仿真软件分析了不同摩擦系数及结构参数条件下摩擦噪声产生的概率,进而研究结构参数对摩擦噪声的影响,进行了平板型和圆弧型结构的水润滑橡胶合金轴承摩擦噪声的对比实验。研究结果表明,水润滑橡胶合金轴承的水槽半径大小、摩擦面形状以及摩擦副的摩擦系数对水润滑橡胶合金轴承的摩擦噪声有较大影响,而水槽的形状对轴承摩擦噪声的影响不大。对一定结构尺寸的水润滑橡胶合金轴承,水槽半径为4 mm、平面型摩擦面的结构可以大大减少轴承出现摩擦噪声的可能性,相关实验结果与计算结果是吻合的。     

稻谷内摩擦角的测定与实验研究

主要对稻谷的内摩擦角进行了测定与实验研究.测定了稻谷的内摩擦角,并探讨了影响内摩擦角的因素.实验结果表明:剪切速度最佳为5.20 mm/min,稻谷的内摩擦角随着法向压力的增大而减小,低速剪切速度变化对内摩擦角的影响不明显,水分变化对其影响也不明显.根据实验结果,拟合出内摩擦角与法向压力的关系方程.     

深部逆断层圆弧形断面诱发煤岩动力灾害的力学分析

为了探索逆断层附近易于发生煤岩动力灾害的力学机制,构建了由构造应力为主导的圆弧形断层面简化力学模型,得到了构造应力以及由其引起附加垂直应力的分布规律,进而建立了断层上盘逆冲滑动临界角度的数学模型。研究表明：水平构造应力与附加垂直应力随着断层倾角的增大而增大,当断层倾角接近90°时,附加垂直应力突然增大且其值数倍高于水平构造应力;基于逆断层滑动的力学分析,理论计算了煤层沿断层逆冲滑动的临界角度,这将对煤岩动力灾害的危险性预测有一定的参考意义。     

多球果型马尾松的形态和生殖生物学特征研究

本文对多球果型马尾松和常见型马尾松在生长状态、形态结构、生殖发育等方面的差异进行研究和分析.在多球果型马尾松雌性生殖枝上,能够着生40～80个球果(大孢子叶球),有的甚至可以达到193个以上.而在常见型马尾松的雌性生殖枝上, 通常只着生有1～8个球果,最常见的是着生2～4个球果.多球果型马尾松和常见型马尾松在雌球花的芽组织结构和雌球花的分化过程中有着明显的差异.通过显微分析我们发现:多球果型马尾松雌球花原基的发育在当年生过冬顶芽的下部,在它的上部,还发育有一系列的营养芽原基(10列以上).而常见型马尾松雌球花原基的发育在当年生过冬顶芽的顶端.雌球花发育机理的不同,决定了多球果型马尾松球果的着生部位发生了变异.多球果型马尾松球果着生在春梢的下(基)部,常见型马尾松球果着生在春梢的顶部.多球果型马尾松与常见型马尾松球果(大孢子叶球)的发育过程和发育起始时间不相同.通过对8～12月标本进行显微切片分析,多球果型马尾松球果的发育起始时间在当年的8月(过冬顶芽开始形成的同时),与小孢子叶球的发育起始时间同步.常见型马尾松球果的发育起始时间是当年的11月,两种类型马尾松的大孢子叶球都是在次年4月受粉,到第三年的11月种子成熟.多球果型马尾松球果比常见型马尾松球果多3个月的发育时间.多球果型马尾松个体大量的长串状多球果性状在历年都能重复出现,这说明该性状具有个体水平的稳定性.无性繁殖研究证明,多球果型马尾松的长串状多球果性状,可以通过嫩枝嫁接的方式,进行性状的传递.对多球果型马尾松进行有性繁殖研究时我们发现,多球果型马尾松的球果可以发育出种子,且成熟种子的发芽率为60%～76%.这说明多球果型马尾松与常见型马尾松一样,可以用种子进行后代繁殖.多球果型马尾松与常见型马尾松在形态和生长速率方面没有明显差异.     

离子注入辣椒出苗特性的研究

采用生物改性离子注入设备对辣椒干种子进行了N+离子注入,详细进行了干种子注入N+离子后的育种和生长特性研究,主要研究了N+离子注入后辣椒种子的出苗率、出苗时间与N+离子注入工艺参数之间的关系,通过研究,获得了致死率为50%的离子注入工艺参数,同时,得到了离子能量和注入剂量相关的致死临界曲线,该致死临界曲线类似于反比例曲线。研究表明,致死临界曲线上任一点的离子能量和注入剂量之积在2×1017keV.ions/mm2-2.5×1017keV.ions/mm2范围内,即当离子能量与注入剂量之积大于2.5×1017keV.ions/mm2时,种子全部致死,当离子能量与注入剂量之积小于2×1017keV.ions/mm2时,将有一定比例的种子存活。     

Reserach on the Die Forging CAD System of Long Shaft Type Forgings

This paper,by using AutoCAD Advanced Modeling Extension(AME),solvesthe difficulty of three-dimensional solid object modeling of forging die CAD on a porsonal computer,sets up the die forging CAD system(DFCAD system)of long shaft type forgings. It is convenient todesign die forging processes and forging dies , and can get 3-D and 2-D forging die drawings.     

Influence of Transverse Flexural Crack on Chloride Penetration in Concrete

The mechanism for chloride penetration in cracked concrete and its major impact factors were analyzed. As a result, a revised chloride diffusion model based on Fick's Law was built by dual porous medium model. Then several cracked reinforced concrete beams self-anchored with sustained flexural loads were immersed in the 5% NaCl solution with the condition of dry-wet cycles. After 15 times of dry-wet cycles, the rapid chloride testing (RCT) was used for the determination of chloride ion content of the powder at each cracked sections. The test results show that: 1) with the condition of dry-wet cycles, the chloride content will occur a peak in the surface 20mm concrete, so the depth for surface convection zone can be assumed to be 15~20 mm; 2) when the crack width is less than 0.3mm, the equivalent chloride diffusion coefficient increases steadily, which agrees well with model's prediction; when the crack width is larger than 0.3mm, the equivalent chloride diffusion coefficient augments rapidly and influence of convection on chloride penetration becomes more significant; 3) the deterioration factor for equivalent chloride diffusion coefficient in flexural cracked concrete is directly correlative with crack width, which can be expressed by second order power function or separate function.     

青海省连阴雨监测指标的修订及其时空特征研究

旨在利用青海50个气象站1961—2015年的4—10月逐日降水、云量和日照资料,通过对日照时数与云量的关系研究,修订青海连阴雨监测的新的指标,并对阴雨日数的时空分布及强度变化进行分析。结果表明：（1）修订后青海连阴雨天气监测指标为：连续阴雨5天（期间日平均日照时数≤6 h）或以上,且过程总降水量≥10 mm,期间不能出现2个无雨日,即日降水量不得<0.1 mm;（2）青海阴雨日数自东向西呈递减趋势,青南地区阴雨日数最多,环青海湖地区次多,柴达木盆地地区最少;（3）1961—2015年青海年平均阴雨日数无明显的变化趋势,但在年代变化上经历了1961—1989年的常态时段、1990—2002年的减少时段以及2003—2015年的增多时段3个变化阶段;（4）青海阴雨日数主要出现在6、7、9月份,都达到了8天以上,其次为8月份, 4月份和10月份最少。本研究修订了青海连阴雨天气的监测指标,并依此开展连阴雨天气预报预警业务,为气象防灾减灾建设提供参考信息。     

门架式抗滑桩结构模型试验研究

为了对门架式抗滑桩的结构特性有进一步的认识和提升,进行了门架式抗滑桩三维地质力学模型试验与门架式抗滑桩结构模型试验。通过在桩身内部贴置应变片以及桩身的关键位置处放置千分表,来测量在推力荷载施加过程中,门架式抗滑桩的桩身应力变化特点及关键位置点的位移变化特征。试验结果表明：门架式抗滑桩桩前、后排桩桩顶位移大于滑动面处位移,后排桩桩身位移大于前排桩桩身位移;前、后排桩桩身内力均呈现明显的“s”型分布,桩顶应力不为零,其数值随着推力荷载的增大的而增大。     

冻结气温降幅对潜水入流量影响的试验研究

为了揭示冻结气温降幅对潜水入流量的影响,通过室内冻结试验装置设定地下水位埋深为87.5 cm,进行了3种冻结气温降幅,2种土壤质地的单向土壤冻结试验,监测潜水入流量的变化。结果表明：大幅降温冻结下,潜水入流速率较大,冻结第41天砂壤土和粉质粘壤土潜水入流量分别较小幅降温冻结下的潜水入流量高51.8 mm和50.7 mm;冻结气温降幅越大,潜水入流量受土壤质地的影响越明显,小幅降温、中幅降温和大幅降温冻结下,第41天砂壤土潜水入流量较粉质粘壤土潜水入流量分别高8.6 mm、11.5 mm和14.2 mm;土壤颗粒直径越小,潜水入流量对冻结气温降幅的响应越早。研究成果对于地下水浅埋区地下水资源量的科学评价和土壤盐碱化防治等具有重要的指导意义。     

Ideotype design for lodging-resistant wheat

The plant characteristics required to make wheat lodging-proof for the least investment of biomass are calculated using a validated model of the lodging process and information about the dry matter costs of altering lodging-associated characters. The plant characteristics required to give a crop yielding 8 t ha⁻¹ with 500 shoots m⁻² and 200 plants m⁻², a lodging return period of 25 years include a height of 0.7 m, a root plate spread of 57 mm, and for the bottom internode a wall width of 0.65 mm with a diameter/material strength combination ranging from a diameter of 5.86 mm with a material strength of 20 MPa to a diameter of 4.00 mm with a material strength of 50 MPa. It is estimated that this ideotype would require 7.9 t ha⁻¹ of stem biomass and would have a harvest index of 0.42. Observations of a wide range of varieties grown using crop management to maximise lodging resistance without reducing yield potential showed that the root plate of the best variety was 7 mm less than the ideotype target, the stem character targets were achieved but not all in one variety, and the height target was achievable with the use of plant growth regulators. Plant breeders must therefore focus on selecting for a wider root plate and combining the appropriate stem strength characteristics.     

Analysis of Large Caisson Sinking Measured Resistance

In the sinking process of large-scale caisson, the distribution of the shaft friction and the end resistance is the main controlling factor of the sinking feasibility, but the research based on large-diameter piles and small or medium-scale caissons are no longer applicable. With the real-time monitoring data of the south anchorage caisson sinking process of Yangtze River Highway Bridge in Ma An Shan, this paper analyses the underlying principles and the mechanical characteristics in the sinking process of the large-scale caisson foundation, Verify the applicability of different formulas of the foundation ultimate bearing capacity in the of the caisson; Contrast sink to different depths , the value and the distribution rules of the shaft friction and the end resistance, this paper also modifies the formulas and distribution characteristics of the shaft friction proposed by current specifications, and the conclusions are suitable for reference of similar scale projects.     

Experimental Study of Flow and Heat Transfer in Heat Exchanger with Small Channels

The experimental study of the flow resistance and heat transfer characteristics are conducted for water and ethylene glycol solution (66% Wt) flowing in the heat exchanger with small rectangular microchannels . The heat exchanger having the channels of 0.4 mm in width, 2.0 mm in height, and 20 mm in length is heated by a hearing rod at the bottom surface, the upper and two side surfaces are adiabatic. During experiments, the Reynolds number are ranged from 2 to 2 500. The experimental results show that the flow friction factor decreases and Nusselt number increases with increasing Reynolds number for water and ethylene glycol solution. At a fixed Reynolds number, the Nusselt number for ethylene glycol solution with larger Prandtl number is greater than that for water. Meanwhile, the correlations of flow resistance and heat transfer in the heat exchanger with small channels are obtained for engineering application.