双向驱动井径测井仪推靠系统工作行为分析

针对单向驱动井径测井仪存在的启动响应慢、速度集中和初始运动冲击等问题,提出一种具有双向驱动特征的新型结构井径测井仪,并对其推靠系统(实现测量臂伸缩)双向驱动过程进行矢量化建模求解及工作行为分析(运动性能仿真、测量性能仿真)。首先进行双向驱动测井仪推靠系统物理建模和理论研究,以双驱动丝杠系统参数(速度、位移)为输入,采用复数矢量法对测井仪推靠系统运动性能参数(位移、速度、加速度)进行参数化表征;然后以实际双驱动推靠系统为对象进行实例分析,对其运动特性进行理论求解,得到推靠杆端口和推靠销钉的运动曲线,并对双驱动速度匹配特性进行研究;最后基于ADAMS进行测井仪工作行为分析,将仿真与理论结果进行对比,结果表明推靠系统仿真运动曲线与理论解析曲线具有较高的吻合度,证明了测井仪推靠系统矢量化建模求解的正确性。     

微球聚焦测井仪推靠系统运动学分析

微球推靠系统是辅助微球聚焦测井仪完成井下测井任务的辅助测井设备,其运动的精确性与测井数据的准确性紧密相关。为进一步提高推靠系统的传动性能,现采用矩阵解析法建立了微球聚焦测井仪推靠系统的数学分析模型,并建立了该推靠系统的虚拟样机模型。对微球聚焦测井仪推靠系统多杆机构进行了运动学分析,研究和分析了推靠系统中两处柱销滑槽高副机构的运动规律以及机构中输出构件推靠极板的运动曲线,得到了推靠系统各杆件运动参数。这些运动参数真实反映了各杆件的运动状况,为推靠系统结构设计和推靠系统的结构参数优化提供了依据。     

木门堆垛机器人真空吸附装置设计与仿真分析

为满足定制化木门生产线的要求,设计一种通用程度高、吸附性能好的真空吸附装置。分析真空吸附装置的结构和原理,完成机械结构和吸附系统的设计。对木门的吸附过程进行理论分析;利用ANSYS对真空吸附装置进行有限元分析;对木门的堆垛过程进行运动仿真分析。求得吸附木门所需的最小理论吸力;得出吸附50 kg木门时真空吸附装置的应力应变情况及吸附装置的前6阶模态;得出堆垛过程大臂、小臂、真空吸附装置的位移、速度等特性曲线。结果表明：真空吸附装置最大应力小于材料的屈服强度,且变形较小、结构稳定,但吸附装置的最大固有频率接近机器人电机的回转频率,易产生共振。通过仿真模拟木门堆垛机器人的运动情况,并获得运动特性参数。研究结果为定制化木门生产线实际作业提供参考。     

基于ADAMS的六自由度液压动感平台建模及运动学仿真

根据Stewart结构制作了一个六自由度运动平台,并以该平台为主要研究对象,构建了整个位姿系统的模型。运用SolidWorks和ADAMS软件,构建平台仿真模型并进行仿真分析,得出上平台以及各缸体的运动特性曲线,验证平台设计的合理性与准确性。同时分析了整个平台机构的运动过程、运动的极限位置、转角、干涉情况、空间运动位置和运动参数等,对整个六自由度液压系统的安全性及可靠性有重要的指导作用。     

双臂协作机器人运动可靠性评估

针对双臂协作机器人精度要求高、工作状态难采样的特性,基于二次四阶矩估计法提出一种双臂协作机器人可靠性分析模型,对机器人位置误差进行分析。利用极值分布原理将系统转换为串联系统,采用随机变量的各阶矩得出极限状态函数的各阶矩;通过最佳平方逼近方法确定极限状态函数的概率密度函数,从而实现单机械臂的可靠度求解,再采用体系可靠性方法对双臂协作机器人的可靠度进行求解。最后,以六自由度双臂协作机器人为例进行分析,通过与蒙特卡洛仿真比较,验证了该方法的有效性。     

六自由度焊接机器人大臂模态分析及优化

针对六自由度焊接机器人大臂的结构特点,运用有限元分析方法,建立了大臂的有限元计算模型,进行模态分析,给出了大臂前六阶固有频率和相应振型。对影响大臂动静态特性的结构参数进行灵敏度分析,确定了大臂主要结构参数对低价固有频率、最大变形量和质量的影响规律,指出大臂的结构优化方向。通过改变结构参数对大臂进行优化,改善了大臂的动静态性能,减轻了大臂的质量,为机器人其它零部件的优化提供了可借鉴的方法。     

一种新型凸轮实验装置设计及分析

为解决传统机械中设计凸轮机构周期长、精确度低、实验研究参数对应关系不直观等客观性问题,设计并制造出了一种新型凸轮实验研究装置。凸轮实验装置在结构设计中使用同步带提高运动精度,线性导轨提高装置的运动稳定性,从而保证了凸轮机构的设计精度。该装置是一种从几何、运动、力学三方面特性来对凸轮研究的实验仪器,采用旋转变换原理和平移变换理论以及运动的合成与分解思想对凸轮轮廓线设计装置及从动件运动规律曲线研究装置进行理论性分析,同时建立了三维有效模型,运用UG运动分析工具箱对两种实验装置进行了实例验证,并且用实际凸轮实验装置在专用实验图纸上设计了凸轮轮廓线,分析了推杆运动规律曲线之间的关系及从动件运动规律曲线的推(回)程、推(回)程运动角、远(近)休止角、冲击点等参数。最后对UG分析和实际凸轮实验装置设计的凸轮及测得数据进行对比,验证得出新型凸轮实验研究装置能够满足要求,具有很高的实用性。     

平行连杆式锻造操作机吊挂系统的关键参数

针对平行连杆式锻造操作机吊挂系统关键参数的确定依据尚不完善的问题,基于锻造操作机末端执行器的输出状态,结合实际工况将吊挂系统的整体结构分为平升降、倾斜及缓冲机构,对应有平升降、倾斜及缓冲运动,通过分析各运动下的运动轨迹及受力状态,并将极端工况作为机构参数确定的约束条件,明确了各机构的影响因素,确定了相关参数。根据以上研究思路,理论分析计算了30 t操作机的吊挂系统,并与同类在用设备进行了比较分析。结果显示：30 t操作机的吊挂系统可以减少能耗、减缓前转臂负荷和更好地吸收振动冲击,验证了研究成果的可行性和实用性,为锻造操作机吊挂系统的结构设计和理论研究提供了一种可行的思路和方法。     

基于SAPSO-GA算法的高速曲轴随动数控磨床几何误差辨识方法

以某型数控曲轴磨床作为研究对象,对其结构和运动进行分析,推导出曲轴磨削时理想的砂轮轨迹方程。根据多体系统理论建立含有误差参数的模型,并推导出机床-工件和机床-刀具的运动链位置矩阵,得出机床精密加工的约束方程。对磨床的几何误差进行研究,建立几何误差模型。为快速、准确辨识出各项几何误差,提出一种混合SAPSO-GA算法。通过对比球杆仪测量补偿前后的运动轨迹,分析补偿效果。结果表明:所提方法提高了辨识准确性,通过补偿大大提高了曲轴随动磨床的加工精度。     

基于飞轮储能原理的挖掘机动臂势能回收系统设计

针对挖掘机工作装置在下放时势能转化为热能造成的能量浪费问题,提出一种以液压泵/马达作为能量转化元件、飞轮为储能元件的动臂势能回收与再利用系统,阐明系统工作原理。以某4 t液压挖掘机为研究对象,对系统的关键参数进行匹配,建立系统模型;对典型工作循环中,对液压泵/马达排量、飞轮转动惯量等关键参数对动臂运动和能量回收和再利用的影响进行仿真分析,得出能量回收和再利用的具体数值,最高可达约65%。结果表明,该系统可以显著提升挖掘机液压系统的能量利用效率。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.