海底盾构隧道双层衬砌 柔性垫层研究

针对大连地铁5号线工程梭鱼湾南站单洞双线盾构区间隧道施工建设问题,探讨岩溶发育区海底隧地铁盾构隧道支护技术。考虑岩溶发育地区工程地质情况复杂及在特殊工况,如地震作用下,结构发生附加变形时的隧道安全,提出使用盾构隧道双层衬砌结构及柔性柔性垫层,通过理论分析、数值计算等方法,分析一定强制位移条件下,不同厚度及密度的柔性垫层对盾构隧道双层衬砌结构内力分布的影响。研究结果表明：随着材料密度的增加,隧道外衬所受最大弯矩先减少后增加,而内衬所受最大弯矩先增大后减小。相同密度情况下,随着材料厚度的增加,外衬最大弯矩逐渐增大,内衬最大弯矩逐渐减小。当柔性垫层材料性能适中能提供充分的协调变形空间时,隧道内外衬砌能合理分配结构附加变形产生的内力,从而大幅提高隧道支护的安全性能。     

摩托车悬架装置结构参数分析及设计

摩托车悬架装置,对摩托车的乘坐舒适性和行驶平稳性有着重要的影响,如果悬架装置设计不合理,会加剧整车共振;振动频率设计或加速度设计不合理,骑乘时会手麻,脚麻;刚度设计不合理,也会影响舒适性。通过分析悬架结构、刚度及频率,来解决悬架设计不合理引起的共振、承载过小、频率过高等摩托车高速行驶时的不稳定问题,通过合理设计解决共振、振动频率与人的步行频率一致问题。     

Full vehicle simulation using thermomechanically coupled hybrid neural network shock absorber model

In the case of full vehicle models, the technique of multi-body simulation (MBS) is frequently used to study their highly non-linear dynamic behaviour. Many non-linearities in vehicle models are induced by force elements like springs, shock absorbers, bushings and tires. Commonly, spline functions are used to represent the force responses of these components. If the non-linear relationships are more complicated, the spline approximations are no more accurate. An alternative approach is based on empirical neural networks which are based on the mathematical approximation of measured data. It is well known that neural networks are able to represent and predict complex component responses accurately. The aim of this paper is to perform a dynamic full vehicle simulation using a thermomechanically coupled hybrid neural network shock absorber model. In this shock absorber model, the spline approach is combined with a temperature-dependent neural network. Based on a displacement-controlled excitation on a four post test rig in the ADAMS/Car MBS software, a rugged test track is simulated. In this way, the front and rear shock absorbers are dynamically loaded with comfort-relevant frequencies in the range of 0.75-30 Hz and velocity amplitudes up to 2 m/s. By the simulation, stability of the hybrid neural network model is demonstrated. Furthermore, the damping force, the vertical acceleration of the chassis and the required simulation times are compared. The standard spline approach is used as a reference.     

浅析正三轮摩托车的方向把抖动

正三轮摩托车方向把抖动是由于前转向系的不规则振动造成的，前轮的振动靠前减震器的阻尼来消除，因此前减震器的刚度及阻尼的匹配是一项非常重要的研究内容。     

人工神经网络在冲击响应计算中的应用

基于人工神经网络在系统辨识和函数拟合方面的优势,以单自由度隔冲系统为研究对象,提取了决定冲击响应的几个参数作为网络输入,以最大响应加速度值和隔振器最大变形量为最终目标参数,采用人工神经网络的方法来计算其冲击响应,实际计算结果表明神经网络方法计算的结果具有较好的精度。     

一维激波结构的数值分析

建立了一维激波结构模型,对Burnett方程进行简化得到STNM方程,通过在均匀网格上采用二阶空间差分对无量纲化后的STNM方程进行数值计算,得到了激波内部参数变化剖面。以氩气为研究对象对一维激波结构进行数值分析计算。结果表明随着马赫数增大,omage数对于激波结构的影响增大,在相同omage数条件下,马赫数变化对激波内部参数变化的影响显著。     

高速列车减振器阻尼特性的影响因素分析

节流阀结构是影响减振器阻尼特性的主要因素,为了得到其结构参数,作者建立了高速列车二系横向减振器内流场的仿真模型。利用计算流体力学的方法分析减振器内部三维动态流场,得到节流阀阻尼孔的尺寸以及开阀阻尼力和开阀速度,并分析了开阀速度和油液温度对减振器阻尼特性的影响。计算结果表明：调节节流阀参数可以得到满足减振器性能要求的阻尼特性;高温时减振器阻尼力减小的两个主要因素是节流阀片易开启以及油液动力黏度降低;开阀速度极小的改变会引起减振器阻尼力发生较大的变化。     

Hybrid neural network model for history-dependent automotive shock absorbers

The method of numerical multi-body simulation is an often used and well-understood development tool in the automotive industry. In order to reproduce the ride comfort or handling behaviour of vehicles, mathematical models have to be built up. To achieve accurate simulation results, highly detailed component models are required. However, the formulation of appropriate physically-based model equations of complex automotive components (e.g. air springs, shock absorbers, rubber bearings, tyres, etc.) can be very difficult. To handle this, empirical modelling methods have been developed. Simple algebraic equations are used to describe complex system behaviour. This simplification is very effective, although it largely ignores the natural laws of mechanics and thermodynamics but is still capable to predict the component response. This article illustrates how to take advantage of this approach in numerical simulations. We describe the development of a hybrid automotive shock absorber model based on both spline and neural network (NN) approaches. By combining these different approaches, an accurate model is achieved without loss of variability. Non-isothermal laboratory force-displacement measurements of an automotive shock absorber are being used to estimate the parameters of the NN. As shown, the model replicates the measured data with sufficient accuracy, especially the hysteresis. Finally, we present a set of quarter-car simulations with a built-in hybrid NN shock absorber.     

车用减振器的外特性建模与仿真

针对某轿车的弹性阀片和弹簧结合型减振器的结构形式，建立了减振器复原行程开阀前、开阀后及压缩行程的阻尼力力学模型，推导出了减振器阻尼力的计算公式，并通过计算机仿真得出该轿车减振器的模拟工作特性。计算机仿真和生产实践证明，所建立的数学模型是正确的，计算方法也符合实际要求。     

汽车筒式液阻减振器技术的发展

分析了汽车乘坐舒适性／行驶平顺性和操作稳定性对筒式液阻减振器特性的要求，提出汽车在不同行驶工况减振器特性的要求是不的；分析了被动式减振器的发展历程及非充气和充气减振器的特点，阐述了机械控制式可调阻尼减振器，电子控制式减振器以及电流变和磁流变液体减器等的结构特点，工作原理及其动态特性；分析了筒式液阻减振器其于经验设计／实验修正开发方法的缺点，阐述了基于CAD／CAE技术的现代设计开发方法的过程及其关键问题，最后分析了我国筒式液阻减振器技术的发展状况及问题，展望了减振器技术的发展前景。