随车起重机变幅机构的动力学分析

基于等效元素法建立了随车起重机变幅机构的动力学模型，得到了其动力学方程，在ADAMS平台上进行动力学仿真，为机构优化设计及控制提供了理论依据。     

摊铺机压实机构的一种动力学模型及其运动分析

本文提出了一个3自由度的摊铺机压实机构的动力学模型,在此基础上,推出该机构中的前后压实梁、振捣器和熨平板平台自身的振动响应公式,并对其作了计算机仿真。     

基于ANSYS的吊篮悬挂机构动力学分析

基于ANSYS对ZLP800高空作业吊篮悬挂机构进行瞬态动力学分析,通过对悬挂机构在不同工况下的动力学求解,获得起升瞬间载荷对悬挂机构的动态冲击动力学响应,计算获得起升动载系数。同时,求解获得悬挂机构加速度、速度及位移曲线,并对曲线进行分析。     

联邦德国BSA1400H—E混凝土泵分配机构的动力学分析

在“联邦德国BSA1400H-E混凝土泵分配机构的结构与运动浅析”一文中,本文作者已经从运动学的角度,对分配机构S形管阀的运动特性做了比较详尽的分析和说明,本文试图在这一基础上对分配机构的动力学特性做进一步的探讨,这种分析方法也许能为混凝土泵分配机构的设计提供一种新思路。     

履带车辆差速式转向机构动力学分析与比较

章在分析传统的离合器式转向机构存在的缺点的基础上,对卡特公司R系列推土机和小松公司X系列推土机所采用的主动差速式转向机构作了介绍,并分析了它们在差速时的转速,力矩和功率,指出它们所具有的优点。     

风电维修起重平台夹紧机构的动力学分析

利用ProE软件建立风电维修起重平台及夹紧机构的三维模型,利用ANSYS Workbench中的瞬态动力学分析模块对夹紧机构在吊臂突然加载和突然卸载这两种危险工况下进行动力学分析,得到夹紧机构连接点处的位移,速度和加速度随时间的响应曲线。模拟风电维修起重平台在实际工作中可能遇到的危险工况,对保证风电维修起重平台安全的夹紧机构进行动力学分析,完成对维修平台的整机稳定性分析,确保了维修平台高空作业的可靠性。为风电维修起重平台的设计制造提供参考,有一定借鉴意义。     

基于刚柔耦合的折叠臂变幅机构动力学分析

通过ADAMS和ANSYS软件建立26m高空作业车折叠臂变幅机构柔性体模型,由ADAMS软件对变幅机构的变幅工况进行仿真分析,得出了变幅机构的应力和位移变化曲线,并与ANSYS静力学分析结果作比较,为合理布置机构铰点和减轻机构重量提供了依据。     

液压起升机构非线性动力学特性分析

本文建立了液压起升机构的含有刚度慢变参数的非线性多自由度动力学模型,并用模态分析和ＫＢＭ方法得到了系统非线性方程的一次及改进的一次近似解。作为比较,又采用数值方法求得系统方程的数值解。分析了液压系统的动态特性,为起升机构的设计提供理论依据。     

汽车起重机动力性的计算机辅助设计

用计算机辅助设计方法来确定汽车起重机的动力性指标，简化了计算，为合理选择发动机和传动系参数提供依据，本方法程序简单，易于实现。     

Report of the working group on dynamics

This review article was especially prepared for possible use of code designers. Its purpose is to frame standard dynamics problems and algorithms within classical structural reliability schemes.     

On the dynamics of taut mooring systems

The dynamics of vertical tauttethers for compliant offshore platforms are assessed using three types of dynamic analysis and the resulting models are compared. An analytic linear model is derived as a basis for comparison with a linear modal analysis as well as with both linear and nonlinear finite element models. It is shown that the linear finite element analysis can predict the behaviour of the continuous tether with adequate accuracy over the frequency range of interest. The finite element model is subsequently used to study the effect of spatial variation of tether tension due to self-weight and square law damping. The validity of equivalent energy dissipative linearization is investigated.     

Modelling the dynamics of design error induced rework in construction

Rework that is experienced in construction projects is often caused by errors made during the design process. Factors that contribute to design errors are identified and used to design and develop a systems dynamics model, which is used to simulate a number of practical scenarios that can be used to reduce design errors and rework. The model presented in this paper can enable design and project managers to understand better the process of design documentation and how design errors occur in construction projects.     

Kinetics and mechanism for degradation of dichlorvos by permanganate in drinking water treatment

The degradation kinetics and mechanism of dichlorvos by permanganate during drinking water treatment were investigated. The reaction of dichlorvos with permanganate was of second-order overall with negligible pH dependence and an activation energy of 29.5 kJ·mol⁻¹. At pH 7.0 and 25 °C, the rate constant was 25.2 ± 0.4 M⁻¹ s⁻¹. Dichlorvos was first degraded to trimethyl phosphate (TMP) and dimethyl phosphate (DMP) simultaneously which approximately accounted for <5% and ≥95% with respect to phosphorus mass, respectively. Further oxidation of DMP generated a final byproduct, monomethyl phosphate (MMP). MMP was for the first time identified as a major byproduct in chemical oxidation of dichlorvos. The kinetic model based on degradation mechanism and determined reaction rate constants allowed us to predict the evolution of dichlorvos and its byproduct concentrations during permanganate pre-oxidation process at water treatment plants. These results suggest that even though the dichlorvos concentration in surface water complies with the surface water quality standards of China (50 μg L⁻¹), its concentration after conventional water treatment will most probably exceed the drinking water quality standards (1 μg L⁻¹). Moreover, luminescent bacteria test shows that the acute toxicity of dichlorvos solution evidently increased after permanganate oxidation.     

超塑化剂作用机理初探

随着混凝土高性能化的不断深入发展，超塑化剂成为提高混凝土性能必不可少的组份，是对混凝土性能影响比较大的组份。但是人们对其作用机理的研究还比较薄弱，这对超塑化剂的开发、生产以及应用是不利的。本文从超塑化剂在水泥颗粒上的吸附、超塑化剂对水化产物的影响和超塑化剂在液相中的作用三个方面对超塑化剂的作用机理做了探讨和研究。在水泥颗粒表面的吸附是超塑化剂分散作用的开始，也是其作用的基础。超塑化剂分子通过其极性官能团错综杂乱的吸附在水泥颗粒的吸附点上，从而改变水泥颗粒表面的物理化学性质，导致颗粒间的斥力增大，达到破坏水泥絮凝结构的目的。本文还介绍了吸附点产生的原因以及其经时变化。超塑化剂通过改变液相中离子的浓度、产生有机溶剂膜和参与产物的形成对初期水化产物的产生、形态等产生影响。液相中的超塑化剂量可以起到补充和分散的作用。最后，作者应用吸附点理论对不同掺量超塑化剂对水泥净浆流动性的影响做了较为详尽的解释。     

Thixotropic mechanism of clay: A microstructural investigation

Clays with high sensitivity exhibit varied degrees of thixotropic characteristics. Previous research has been focused on dilute suspensions, but only a few studies have investigated normal clay with water contents lower than the liquid limit. Given the limited studies performed, the thixotropic behavior of clays and the underlying mechanism remain ambiguous, particularly in the microscopic scale. In this study, samples of Zhanjiang clay from southern China were used to elucidate the thixotropic process. The samples were agitated and then subjected to unconfined compressive strength and pocket penetrometer tests, scanning electron microscopy, and mercury intrusion porosimetry to evaluate their regain strength and microstructure. After 500 d of thixotropy, the strength of the Zhanjiang clay was 2.58 times higher than that after the disturbance and significantly higher than that of the other clays reported in the literature. These findings provide evidence that thixotropy is a process in which the dispersed structure is transformed into a flocculent structure through the homogenization of the pore size distribution caused by particle movement. This phenomenon may be due to the changes in the interaction of attractive and repulsive forces between particles. Given the experimental findings, a thixotropic mechanism for clay is proposed. This study will be beneficial for predicting the strength of disturbed soils.     

A preliminary study of assimilating numerical weather prediction data into computational fluid dynamics models for wind prediction

The goal of this effort is to combine the strengths of Numerical Weather Prediction (NWP) with Computational Fluid Dynamics (CFD) to produce locale-specific flow patterns that could be used for micrositing wind power plants. We do this in two ways: (1) we use the mesoscale model data as inflow for the CFD model and (2) we assimilate vertical profiles of mesoscale model output into the CFD model as a body force. We study the impact of this technique with a case study in the rolling topography of central Pennsylvania. We compare wind profiles between the mesoscale model alone, the CFD model alone, and the fully assimilated mesoscale/CFD solution. In addition, we examine the impact of the mesoscale assimilation into the CFD model on the fine-scale flow structure. This preliminary approach of combining techniques in NWP and CFD through data assimilation provides a unique assessment of the utility of specific locations for wind power production as well as for improving simulations for other purposes.     

水热合成硅酸钙外加剂作用机理探讨

外加剂能显著地改善活性不高的硅质原料水热合成微孔硅酸钙的工艺过程 ,本文就外加剂的作用机理进行了试验研究。     

液压挖掘机工作装置动力学建模与分析

提出一种基于牛顿-欧拉方程的挖掘机工作装置动力学数学模型的推导方法。利用Matlab符号运算功能,编制M文件实现数学模型自动推导,整个建模和运算过程简单、直观和高效。以某中型挖掘机为例进行分析,结果表明模型很好地反映了挖掘机工作装置的动力学特性。