基于ANSYS的装箱机承载轴的优化设计

为提高装箱机的工作效率,装箱机由一次装4箱改为装6箱。为改变抓头部件承载轴出现的弯曲现象,对全自动装箱机的承载抓头部件的轴进行ANSYS优化设计。在ANSYS中对抓头部件承载轴建模并对其进行优化设计,得到实心轴半径,根据其直径,对空心承载轴进行优化设计,最后利用瞬态动力学分析对其结果进行验证。

重载支架搬运车轮边减速器承载轴壳的结构强度分析

通过对煤矿井下重载框架式支架搬运车轮边减速器的典型工况进行受力分析,确定了其减速器承载轴壳的有限元分析的载荷边界条件,进而得出了承载轴壳的强度分析的计算结果,为支架搬运车轮边减速器承载部件的强度校核提供了一种可行的计算方法。该轮边减速器在整机的工业性试验中表现良好。

半挂车承载轴偏斜角对车辆行驶性能影响及检测方法研究

半挂车承载轴偏斜会造成汽车的偏驶现象,为保持半挂车具有良好的技术状况,使其安全、低消耗的运行,最有效办法就是定期对半挂车承载轴进行检测和维修。在分析了半挂车承载轴偏斜角产生的原因及其对车辆使用性能影响的基础上,采用激光测距仪测出左右车轮边缘到半挂车铰接点的水平距离和光电编码器测出激光测距仪所转动的角度,利用距离和角度关系,建立了半挂车承载轴偏斜角的检测数学模型,通过研究,提出了承载轴偏斜角对车辆行驶性能评价的检测方法,为进一步研究承载轴偏斜对半挂车性能的影响提供了理论依据。

基于机器视觉的半挂车承载轴偏斜角的检测方法研究

分析了半挂车承载轴偏斜角产生的原因及危害,建立了基于机器视觉的检测半挂车承载轴偏斜角的数学模型,提出了测量半挂车行驶方向角和承载轴偏斜角的方法。

汽车列车承载轴偏斜危害性分析及检测方法研究

公路运输的不断发展,半挂汽车列车的保有量不断增加。分析了半挂汽车列车承载轴偏斜对汽车使用性能造成的影响,根据其结构分析产生的原因。进而建立汽车列车承载轴偏斜角检测模型,为其承载轴偏斜的不解体检测提供了理论依据。

多功能尾管悬挂器关键技术研究

随着深井、超深井、水平井、高温高压井等复杂井越来越多,固井施工的难度越来越大,常规尾管固井工具及工艺难以满足现场需求。为解决复杂井况下的固井技术难题,研制了新型多功能尾管悬挂器,设计了旋转机构、坐挂机构、液压丢手、顶部封隔等多个功能模块,并采用有限元方法对关键部件进行仿真分析,优化了各功能模块的结构和参数。计算和地面试验证明,各功能模块的性能、功能及技术参数符合设计要求。多功能尾管悬挂器在涠洲WZ6-12-A3S井进行了现场试验,结果表明,该尾管悬挂器对现场复杂井况具有较强的适应能力和可靠性。

主动控制轴力作用下基坑围护结构强度研究

伺服钢支撑可通过主动补偿损失轴力控制基坑变形,虽应用良多但对其作用的围护结构强度问题研究甚少。基于力学原理,采用增量法对不同钢支撑轴力作用下的围护结构强度进行计算,得到了不同工况作用下围护结构的弯矩、剪力变化规律。以上海浦东南路站2号出入口基坑和浦东南路站基坑工程为依托,采用Plaxis 2D数值模拟并得到了不同伺服钢支撑轴力施加工况以及极限承载状态轴力组合工况下的围护结构内力分布。结果表明,在伺服钢支撑轴力逐渐增大作用下,围护结构迎土侧弯矩逐渐增大,背土侧弯矩先减小后增大,剪力先减小再增大,最大弯矩与最大剪力均未超过地连墙可承受极限值,背土侧配筋需结合伺服钢支撑轴力相应提高配筋率;各伺服钢支撑极限承载组合工况中若干工况超过地连墙设计极限值,采用伺服控制系统不可依靠单一增加作用力来提高主动控制效果。

公安部交通管理局发出通知调整部分车型制动性能检验要求

公安部交通管理局发出通知调整部分车型制动性能检验要求本刊讯近日，公安部交通管理局发出《关于调整部分车型制动性能检验要求的通知》。通知指出，根据《机动车运行安全技术条件》（ＧＢ７２５８－８７），对机动车制动性能规定了制动减速度：制动距离、制动力三种检测...

夯实整车金字塔底座——全力打造自主品牌的汉德车桥

随着国际重卡巨鳄的纷纷涌入,在"拿来主义"之风盛行下,保护民族自主品牌已刻不容缓.

EFFECTS OF MANUFACTURING ERRORS ON GAS LUBRICATED JOURNAL BEARING WITH COMPLIANT SURFACE

A theoretical study has been performed to investigate the influence of manufacturing errors on the bearing housing of a gas lubricated journal bearing with compliant surface I in particular on the bearing load capacity. A gas film thickness distribution is presented, in which errors o f both circumferential and axial bearing housing are considered. The influence of the errors on bearing performance is compared between rigid and compliant surface bearings. It was shown that the compliant surface bearings are less sensitive to the manufacturing errors than the rigid surface bearings. Thelefore, the cost of compliant surface bearing could be reduced by setting a larger manufacturing error tolerance.

Entrance Effect on Load Capacity of Orifice Compensated Aerostatic Bearing with Feeding Pocket

The current research of the aerostatic thrust bearing mainly focuses on the porous material bearing and inherent compensated air bearing, which aims at obtaining small physical dimension and large load capacity. Although porous material bearing appears larger load capacity, materials anisotropy itself and void content distortion caused in heat-treating, and machining processes add greater complexity to internal flow transfer process. Inherent compensated air bearing has the advantages of simple structure and good stability, but its load capacity and static stiffness is not worth somewhat. In this paper, based on hydrostatic lubrication theory, finite volume method is presented for taking entrance effects into account in computing pressure distribution, load capacity and mass flow rates of circular aerostatic thrust bearings. Technical analysis, numerical simulations and laboratory demonstration tests of influence of pocket diameter and pocket depth on loading capacity of aerostatic thrust bearing are carried out on simple orifice compensated air bearings with feeding pockets. The static parameters, such as air consumption and pressure distributions, are measured as a function of supply pressure and air gap height for several different orifices and pockets size. Entrance effects are described in term of typical throttling types, and the effect of pocket diameter and pocket depth on load capacity is systematically described respectively. The proposed research results uncover the causation of throttling action of the orifice compensated air bearing with feed pocket and further develop and improve the design theory of air bearing.

Parametric analysis of thermal effect on hydrostatic slipper bearing capacity of axial piston pump

Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.

Bearing capacity and settlement of strip footing on geosynthetic reinforced clayey slopes

The effect of geosynthetic reinforcing on bearing capacity of a strip footing resting on georeinforced clayey slopes was investigated.The results of a series of numerical study using finite element analyses on strip footing upon both reinforced and unreinforced clayey slopes were presented.The objectives of this work are to:1) determine the influence of reinforcement on the bearing-capacity of the strip footings adjacent slopes,2) suggest an optimum number of reinforcement and 3) survey the effect of friction angle in clayey soils reinforced by geogrids.The investigations were carried out by varying the edge distance of the footing from slope.Also different numbers of geosynthetic layers were applied to obtaining the maximum bearing capacity and minimum settlement.To achieve the third objective,two different friction angles were used.The results show that the load?settlement behavior and ultimate bearing capacity of footing can be considerably improved by the inclusion of reinforcing layer.But using more than one layer reinforcement,the ultimate bearing capacity does not change considerably.It is also shown that for both reinforced and unreinforced slopes,the bearing capacity increases with an increase in edge distance.In addition,as the soil friction angle is increased,the efficiency of reinforcing reduces.

Finite element analysis of effect of soil displacement on bearing capacity of single friction pile

Effect of soil displacement on friction single pile in the cases of tunneling,surcharge load and uniform soil movement was discussed in details with finite element method.Lateral displacement of the pile caused by soil displacement reached about 90% of the total displacement,which means that P-Δ effect of axial load can be neglected.The maximum moment of pile decreased from 159 kN·m to 133 kN·m in the case of surcharge load when the axial load increased from 0 to the ultimate load.When deformation of pile caused by soil displacement is large,axial load applied on pile-head plays the role of reducing the maximum bending moment in concrete pile to some extent.When pile is on one side of the tunnel,soil displacements around the pile are all alike,which means that the soil pressures around the pile do not decrease during tunneling.Therefore,Q-s curve of the pile affected by tunneling is very close to that of pile in static loading test.Bearing capacities of piles influenced by surcharge load and uniform soil movement are 2480 kN and 2630 kN,respectively,which are a little greater than that of the pile in static loading test(2400 kN).Soil pressures along pile increase due to surcharge load and uniform soil movement,and so do the shaft resistances along pile,as a result,when rebars in concrete piles are enough,bearing capacity of pile affected by soil displacement increases compared with that of pile in static loading test.

Strength of circular concrete columns under concentric compression

An experimental study, in which six columns were loaded concentrically toinvestigate the behavior of reinforced normal strength and high strength circular columns underconcentric compression, is described. The concrete strengths of the columns were 30 MPa and 60 MPa.The primary variables considered were the concrete strength and the amount of transversereinforcement. Test results indicate that smaller hoop spacing provides higher column capacity andgreater strength enhancement in a confined concrete core of columns. For the same lateralconfinement, high strength concrete columns develop lower strength enhancement than normal strengthconcrete columns. Both the strength enhancement ratio (f'_(cc) /f'_(co)) and the column capacityratio (P_(test)/P_o) were observed to show linear increase variations with rho_s f_(yt)/f'_c incircular columns.

Mechanical property of single-bolted composite laminates

In order to investigate the effects of different geometrical parameters and pretightening loads on failure mode and bearing strength,a large number of single-bolted T300/QY8911 composite laminates were tested under static tension load.Box-plot was used to extract the singular testing values of bearing strength and effective statistical values were obtained.T-test method of independent samples was used to study how much pretightening loads influence bearing strength.The results show that the geometrical parameters,such as ratios of width to hole diameter(w/d) and edge distance to hole diameter(e/d),remarkably influence failure mode and bearing strength.Net-section failure will occur when w/d is smaller than 4,and shear-out failure will occur when e/d is smaller than 2.Bearing failure or bearing and shear-out combined failure will occur when w/d is greater than 4 and e/d is greater than 2.There is an optimal combination of geometrical parameters to achieve the highest bearing strength.For most of specimens,pretightening loads do not explicitly influence bearing strength.

Axial bearing behavior of super-long piles in deep soft clay over stiff layers

In order to find out the bearing behavior of super-long piles located in deep soft clay over stiff layers around Dongting Lake, China, a test pile was first designed with the field loading test finished afterward. Based on the measured test results, load transfer mechanism and bearing behavior of the pile shaft were discussed in detail. Then, by introducing a bi-linear model for shaft friction and the tri-linear model for pile tip resistance, respectively, the governing differential equation of pile soil system was set up by the load transfer method with the analytical solutions derived as well, taking into account the effect by stratified feature and various bearing conditions of subsoil, material nonlinearity, and the sediment under pile tip. Furthermore, formulas to determine the axial capacity of super-long piles by the pile top settlement were advised and applied to analyze the test pile. Good agreement between the predicted load settlement variations and the measured data is obtained to verify the validity of the present method. The results also show that, the axial bearing capacity of super-long piles should be controlled by the allowable pile top settlement, and buckling stability of the pile shaft should be paid attention as well.

Mechanical behaviors of cross roller bearings with raceway roundness error

Taking the raceway roundness error into account,mechanical characteristics of cross roller bearings(CRBs)were investigated.A static analysis model of CRBs considering the raceway roundness error was established.Based on this model,the rotational accuracy and load distribution of CRBs under constraints of geometry and external loads were derived.The fatigue life of CRBs with roundness error was calculated by applying Palmgren-Miner linear cumulative damage theory.The influence of inner and outer raceway roundness error on the performance of the CRBs,such as rotational accuracy,load distribution,and fatigue life,was studied through the analysis of examples.The results indicate that the influence of roundness error on the rotating inner raceway is more significant than that of roundness error on the nonrotating outer raceway.The roundness error on the rotating inner raceway always degrades the performance of CRBs.However,a proper roundness error on the nonrotating outer raceway can reduce the loads acting on the rollers and thus improve the fatigue life of CRBs.The effect of the roundness error amplitude on the bearing performance is ordinal,whereas the effect of the roundness order on the bearing performance is not in order.

Unified bearing capacity model of confined concrete column subjected to axial compression

To better study the behavior of confined concrete, this paper presents the basic hypothesis of uhimate equilibrium of confined concrete and the unified yield criteria of confining material. Based on the static equilibrium condition and yield criteria of components, a unified bearing capacity model of confined concrete column is proposed, and a simplified calculating equation of the model is also given. The model captures the character of confined concrete column. Effects of the confinement effect ratio, the lateral confinement ratio, unconfined concrete strength and the properties of confining material on the bearing capacity of confined concrete column are carefully considered. The model may be applicable to the calculation of bearing capacity of steel-confined concrete, concrete filled steel tube and FRP-confined concrete. The predictions of the model agree well with test data.