Microstructures and mechanical properties of semi-solid squeeze casting ZL104 connecting rod

Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.

Lubrication Performance of Connecting-Rod and Main Bearing in Di erent Engine Operating Conditions

Only the lubrication performance at rated engine operating condition was generally analyzed in current design and research of engine connecting-rod and main bearing. However, the actual engine(especially vehicle engine) does not always operate in rated operating condition and its operating condition changes constantly. In this paper, a fourstroke four-cylinder engine is taken as the studying object, the load and lubrication of connecting-rod and main bearing in di erent operating conditions are analyzed. The load of connecting-rod bearing is calculated by the dynamic calculation method, the loads of all main bearings are calculated by the whole crankshaft beam-element finite element method, and the lubrication performance of connecting-rod and main bearings are analyzed by the dynamic method. The results show that there are major di erences in the changes and numerical value at corresponding moment of the loads and lubrication performance of connecting-rod and main bearings in an engine operating cycle in di erent engine operating conditions; the most unfavorable case of the lubrication performance of connectingrod and main bearings may not take place in the rated engine operating condition. There are also major di erences between the lubrication performance of connecting-rod bearing and that of main bearing and between the lubrication performances of main bearings one another. Therefore, it will not be reasonable that the lubrication performance of a certain connecting-rod bearing or main bearing is analyzed in the design of the engine bearing. It is necessary to analyze simultaneously the lubrication performances of all bearings in di erent engine operating conditions.

Photoplastic Experimental Research on Material Plastic Flow Law of Connecting Rods during Finish Process

Photoplastic experiment were conducted with connecting rods of AX100 motorcycle engine during finish forging to investigate material plastic flow law of long -axis forgings with comples geometrie’s by observing

Study on CAD/CAE System of Engine Connecting Rod

The intensive competition of automotive market requ ir es shortening the product development circle and improving the product quality. Many of auto manufacturers in china have introduced some CAD/CAE/CAM systems in product development process, and have got some success. But the special and effi cient CAD system aimed at particular product is absent. This paper provides a CA D/CAE system that can realize the integration of CAD and CAE process for engine connecting rod development. The paper discusses some general methods in connecting rod design process, and s ums up structure characteristics of connecting rod. It introduces feature defini tion and feature classification facing connecting rod CAD/CAE system. Based on t he study of the feature technology and the feature of connecting rod, it creates the feature information model and feature database of engine connecting rod . In addition, it creates the parametric model of engine connection rod and real izes variable parametric design and variable structure design. With the help of Pro/Toolkit and Using C++ program to call the user ’s toolbox of Pro/ Engineer software system, the connecting rod CAD/CAE syst em can create connecting rod model automatically to meet the needs of different structure and different type of connecting rod. Based on Pro/Mechanica platform of PTC, the system can implements the Finite Ele ment Analysis and optimization of the connecting rod. Because using the same database in design and analysis, no data lost and no error occurs during da ta transforming. Using the connecting rod CAD/CAE system, the connecting rod can be meshed automatically and the FEA result can be achieved very fast and is very similar to the experiment. In a word, the connecting rod CAD/CAE system developed in this paper can optimiz e the product development process, realize the data share and concurrent enginee ring in the product design and analysis process, shorten the product develop ment circle, and improve the efficiency.

Powder Forging of a Motorcycle Connecting Rod

A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M has been proposed and studied experimentally. In order to achieve uniform density, the punch was divided into three parts to consolidate the loose powder. The multistage movement of the three parts of the punch, called synchronous compaction, results in the desired uniform density. Powder flow during consolidation was illustrated and the density distribution of the compacts was measured. A set of forging dies with flash was used to produce densification and deformation of the sintered compact. Then a set of flashless forging dies was designed to obtain the desired shape and dimensions of the connecting rod. The effects of forging temperature and initial compact density on densification were evaluated through hot forging experiments. Based on properties achieved, Fe-C-Cu-Mo was selected as the

Simulation analysis of wear characteristics of connecting rod bearing bush based on improved mixed lubrication model

The failure rate of crankpin bearing bush of diesel engine under complex working conditions such as high temperature,dynamic load and variable speed is high.After serious wear,it is easy to deteriorate the stress state of connecting rod body and connecting rod bolt,resulting in serious accidents such as connecting rod fracture and body damage.Based on the mixed lubrication characteristics of connecting rod big endbearing shell of diesel engine under high explosion pressure impact load,an improved mixed lubrication mechanism model is established,which considers the influence of viscoelastic micro deformation of bearing bush material,integrates the full film lubrication model and dry friction model,couples dynamic equation of connecting rod.Then the actual lubrication state of big end bearing shell is simulated numerically.Further,the correctness of the theoretical research results is verified by fault simulation experiments.The results show that the high-frequency impact signal with fixed angle domain characteristics will be generated after the serious wear of bearing bush and the deterioration of lubrication state.The fault feature capture and alarm can be realized through the condition monitoring system,which can be applied to the fault monitoring of connecting rod bearing bush of diesel engine in the future.

Modal and Thermal Analysis of a Modified Connecting Rod of an Internal Combustion Engine Using Finite Element Method

The connecting rod is one of the most important moving components in an internal combustion engine. The present work determined the possibility of using aluminium alloy 7075 material to design and manufacture a connecting rod for weight optimisation without losing the strength of the connecting rod. It considered modal and thermal analyses to investigate the suitability of the material for connecting rod design. The parameters that were considered under the modal analysis were: total deformation, and natural frequency, while the thermal analysis looked at the temperature distribution, total heat flux and directional heat flux of the four connecting rods made with titanium alloy, grey cast iron, structural steel and aluminium 7075 alloy respectively. The connecting rod was modelled using Autodesk inventor2017 software using the calculated parameters. The steady-state thermal analysis was used to determine the induced heat flux and directional heat flux. The study found that Aluminium 7075 alloy deformed more than the remaining three other materials but has superior qualities in terms of vibrational natural frequency, total heat flux and lightweight compared to structural steel, grey cast iron and titanium alloy.

关于16PC2-6V400型柴油机连杆断裂故障原因分析及改进措施

针对某船的16PC2-6V400型柴油机在使用过程中出现的连杆断裂飞出,缸套破损,活塞顶卡滞、连杆大段掉落的故障现象,结合故障出现的环境和使用工况进行分析,通过建立故障树,对各故障原因进行排除,定位故障部位,通过对故障件进行微观形貌分析,明确故障为连杆螺纹根部刀痕应力集中处促使裂纹源萌生并以疲劳的方式发展最终断裂。针对该故障暴露的问题,提出具有可行性的解决方法,避免再次因该类型问题导致较大故障及损失的发生。

Analytical models for the penetration of semi-infinite targets by rigid,deformable and erosive long rods

A theoretical study is presented herein on the pen- etration of a semi-infinite target by a spherical-headed long rod for Yp 〉 S, where Yp is the penetrator strength and S is the static target resistance. For Yp 〉 S, depending upon initial impact velocity, there exist three types of penetration, namely, penetration by a rigid long rod, penetration by a deforming non-erosive long rod and penetration by an erosive long rod. If the impact velocity of the penetrator is higher than the hydrodynamic velocity （VH）, it will penetrate the target in an erosive mode; if the impact velocity lies between the hydrodynamic velocity （VH） and the rigid body velocity （VR）, it will penetrate the target in a deformable mode; if the impact velocity is less than the rigid body velocity （VR）, it will penetrate the target in a rigid mode. The critical conditions for the transition among these three penetration modes are proposed. It is demonstrated that the present model predictions correlate well with the experimental observations in terms of depth of penetration （DOP） and the critical transition conditions.

基于MCKD-HED-CNN的连杆轴承故障诊断

针对强背景噪声干扰下连杆轴承故障诊断难的问题,提出了基于MCKD-HED-CNN的连杆轴承故障诊断方法。首先采用最大相关峭度解卷积(MCKD)对获取的信号进行降噪处理,增强信号中因故障引起的周期性冲击,其次通过Hilbert包络解调(HED)进一步增强周期性冲击,最后将故障特征通过对称点模式(SPD)映射到极坐标图上,并将SDP图像输入CNN网络进行训练,建立连杆轴承故障诊断模型。结果表明:该方法能有效诊断连杆轴承故障,CNN训练样本和测试样本的诊断准确率均为100%。

Variable-based Ramberg-Osgood constitutive model of power spinning bushing

The influences of power spinning process parameters on the mechanical properties of spinning parts were analyzed with an SXD100/3-CNC numerical control power spinning machine.The unidirectional tensile tests were carried out.Based on the experimental data,a ternary quadratic regression equation was established by orthogonal experiment.The Ramberg-Osgood constitutive model of tin-bronze connecting rod bushing was obtained.Referred to the constitutive relation of macroscopic incremental,the incremental elastoplastic constitutive relation of spinning parts was deduced based on the Mises yield criterion and kinematic hardening model.The results can be applied to the elastoplastic analysis in finite element numerical simulation.

多缸内燃机缸套-活塞系统摩擦学与动力学耦合问题的研究

从理论上对多缸内燃机缸套 活塞系统摩擦学与动力学的耦合问题进行了研究。在纠正了到目前为止被广泛引用的活塞二阶运动方程中的错误的基础上, 给出了多缸内燃机缸套 活塞系统摩擦学与动力学耦合问题的数学模型。在该模型中, 首次在计算活塞二阶运动时考虑了连杆惯性力的影响。并对影响缸套 活塞系统摩擦学行为的主要动力学因素做了深入的论述。最后讨论了缸套 活塞系统摩擦学与动力学之间的耦合作用对活塞侧推力、作用在连杆和主轴承上的力的影响进行了讨论, 并据此对它们的传统计算模型作了修正。

基于AVL-EXCITE的内燃机连杆轴承润滑仿真分析

内燃机连杆轴承的润滑状况对连杆轴承的使用寿命影响很大。随着内燃机的不断强化,对连杆轴承性能的要求也相应提高。因此,深入研究连杆轴承的润滑问题以便更加准确地分析和设计轴承的性能便显得日益重要。首先从理论上阐述了润滑状况对轴承工作可靠性的影响,然后针对某发动机的连杆,在AVL-EXCITE中建立了连杆的柔性多体动力学与动力润滑耦合仿真模型。通过计算得到了连杆轴承的轴心轨迹、最小油膜厚度和最大油膜压力等参数,并比较了转速、轴承间隙和温度对轴承润滑性能的影响。研究结果对连杆轴承动力学耦合分析和优化设计以及判断轴承工作的可靠性具有重要意义。

基于虚拟样机技术的柴油机曲轴-连杆-活塞机构运动学、动力学仿真分析

基于虚拟样机技术及其支撑软件VN4D和Pro/E,实现了对12VPA6柴油机曲轴-连杆-活塞机构的运动学、动力学仿真.通过动态仿真柴油机的运行,获取了仿真模型的运动学、动力学特性数据,得到的结果与理论分析相吻合,这为该型柴油机曲轴-连杆-活塞机构的优化设计和有限元分析提供了依据.

DEFORM-3D仿真软件在连杆锻造过程中的应用

分析连杆锻造过程中的参数选择,利用有限元仿真软件DEFORM-3D实现连杆锻造成形整个过程的数值模拟,在应力、应变分布、载荷计算、材料流动速度、模具填充和毛坯优化等方面做了深入研究,为模具及成形设备的设计提供了可靠的依据。

热挤压-强力旋压-热处理对锡青铜显微组织的影响

以强力旋压工艺加工的高速柴油机连杆衬套为基础,通过金相、XRD和洛氏硬度实验研究热挤压、强力旋压、热处理三种主要工艺对锡青铜合金的金相组织和力学性能的影响。结果表明:热挤压后晶粒稍有细化;强力旋压后,晶粒得到了明显的细化,材料发生加工硬化;退火可消除残余内应力,不改变组织结构。

基于ABAQUS的4V-105柴油机连杆有限元分析

连杆在柴油机中直接与活塞销、曲轴连杆颈连接,通过弹性接触传递力。有限元分析中接触问题一直是个难点,传统的有限元分析中对分析对象与构件间的接触问题,一般采用简化处理。利用ABAQUS有限元软件,采用接触法对4V-105柴油机连杆进行有限元分析,得出了接触面间的压力分布、连杆的应力分布及强度等,并对连杆进行了校核,结果表明,采用40Cr设计的连杆可以满足工作要求。

考虑连杆-曲轴变惯性影响的活塞二阶运动分析

为分析活塞二阶运动轨迹和裙部侧向力,提出一个包括连杆和曲柄动力学在内的活塞动力学和摩擦学耦合分析模型.该模型同时也将活塞环组摩擦力、活塞销和曲轴偏置、配缸间隙对活塞动力学和摩擦学的影响考虑在内.计算和比较了连杆和曲轴变惯性对活塞二阶运动和侧向力的影响,同时也分析了配缸间隙对活塞二阶运动的影响.结果表明,连杆变惯性及配缸间隙都对活塞二阶运动和裙部侧向力有重要影响.