轮胎温度场有限元分析系统的设计与开发

研究轮胎滚动过程中的稳态热平衡状态。通过经验数据积累，从轮胎结构参数设计、断面网格划分和有限元分析、热物性参数数据库建立和温度场计算、试验数据拟合及结果输出五方面，设计轮胎温度场有限元分析系统。通过与试验数据对比，证明输出的温度场云图与稳态轮胎温度场温度分布情况一致。     

全钢载重子午线轮胎稳态温度场试验及仿真分析

以12.00R20全钢载重子午线轮胎为例,在讨论合理施加对流边界条件、计算内部生热率及测定轮胎橡胶热物性参数的基础上,进行稳态温度场有限元仿真分析,并通过轮胎内外温度场试验,证实了所提出的轮胎稳态温度场研究流程的合理性.     

滚动轮胎稳态温度场的有限元计算

建立分析滚动子午线轮胎稳态温度场的有限元模型．采用Galerkin加权余量法求解轮胎的导热偏微分方程，得到轮胎内部温度场分布情况．并与相同工况下的实际轮胎测温结果进行对比。结果表明，该有限元模型是合理的，可以用来指导轮胎结构设计和胶料配方设计等。     

有限元分析在轮胎设计中的应用

综述了轮胎分析理论的发展与内容，介绍了有限元理论在轮胎结构设计中的进展。文中着重介绍了有限元分析技术在轮胎接触以及轮胎在稳态与动态下温度场分布问题上的应用。     

轮胎稳态温度场分布的有限元分析

介绍了轮胎稳态温度分布的有限元静态分析。轮胎滚动温升的主要热源是橡胶-帘线复合材料滞后损失产生的热量。轮胎滚动达到稳态时,温升最高的部位是胎肩和胎圈。同一规格的轮胎在不同行驶速度下的温升不同,达到稳态温度场分布所需的时间不同,但稳态温度场分布大致相同,行驶速度高的轮胎达到稳态温度场分布所需的时间长。     

轮胎稳态温度场的计算

用有限元方法直接对基于能量守恒的热传导微分方程进行求解，计算出轮胎在恒定速度下的稳态温度场，并用红外热像仪进行了轮胎表面温度场的测量。     

实心橡胶轮胎温度场有限元分析

根据高速履带车辆实心橡胶轮胎的工作条件，在合理假设基础上建立了轮胎热分析有限元模型，借助大型有限元分析软件ANSYS，通过对某型实心橡胶轮胎温度场的计算，得到了轮胎内部温度场的分布情况，结果表明，轮胎最高温度随载荷，轮胎断面厚度的增大而升高，随轮胎断面宽度增大而降低。     

滚动轮胎全过程温度场数值与试验分析

基于Ansys软件建立轮胎三维力学模型和二维温度场有限元模型,分析额定工况下轮胎滚动和停止后温度场的分布和变化规律,探讨温降阶段温度场的数值计算方法,并进行试验验证。结果表明,温度场计算数据与试验值在温升和稳态阶段基本一致,而在温降阶段只在一定范围内比较吻合。     

子午线轮胎滚动阻力与温度场非线性有限元分析

提出用非线性有限元法分析子午线轮胎滚动阻力和温度场的方法。总的有限元程序由３个模块组成;变形模块,进行轮胎稳态结构分析以得到轮胎的变形和应力－应变循环;损耗模块,进行轮胎的能量损耗和热生成率分析;热模块,进行轮胎的温度场分析。３个模块联合运用和迭代计算可以进行轮胎热、力耦合分析,预报轮胎的滚动阻力,内部温度场,应力－应变,变形和接地面信息,从而为轮胎设计提供依据。     

双热源作用下轮胎非稳态温度场的研究

同时考虑轮胎胶料滞后热源和摩擦热源的作用对轮胎非稳态温度场进行模拟,并以165/70R10轮胎为例对轮胎从启动到稳态行驶阶段的温度场进行分析.结果发现,在轮胎启动初始阶段摩擦热源对温升的影响不能忽略,但当轮胎进入稳态行驶阶段后,滞后热源成为影响轮胎温升的主要因素,而摩擦热源可以忽略不计.     

实心轮胎温度场的有限元分析

应用ANSYS有限元分析软件模拟履带车辆实心橡胶轮胎在不同工作条件下的力学场,以模拟结果计算节点生热率,再将节点生热率导入合理假设的温度场有限元模型,模拟得到轮胎的温升规律.结果发现,轮胎的最高温度随着载荷、速度和损耗因子增大而提高,但随着导热系数增大而降低.     

Thermal insulation characteristics of roll forming alumina ball material

Rolling ceramic thermal insulation balls have advantages of low cost, large output and easy control of particle size, so it is likely to become the main raw material for 3D printing in the future, but there is little research on its thermal insulation. In this study, we used three kinds of rolling aluminum oxide balls as raw materials to obtain single-granularity-level and multi-granularity-level bulk materials. And the effects of temperature, particle size, and thermal fatigue times on the thermal conductivity of the samples were analyzed. Additionally, the experimental results were verified by FloEFD heat conduction simulation software using finite analysis method to analyze their heat conduction characteristics. With the increase of temperature from 400 °C to 1500 °C, the thermal conductivity of single-granularity-level and multi-granularity-level bulk materials increased linearly. The thermal conductivity of single-granularity-level bulk materials have no direct relationship with the particle size, and the thermal conductivity of multi-granularity-level materials with small particle size difference was a bit lower than that of materials with large particle size difference, and a bit higher than that of materials with single-granularity-level. The simulation results showed that the main reason for the above phenomenon was that the point contact between particles played a dominating role in the heat transfer process. When the contact area increased, the thermal conductivity increased obviously, and the thermal conductivity with the increasing of temperature decreased in a quadratic curve. The improved model considering the shrinkage could improve accuracy of simulation results. Heat flux at the surface contact area was 10.19 times higher than that of the point contact and 15.10 times higher than that of the solid-gas contact at 400 °C. Therefore, reducing the surface contact area and increasing the porosity could significantly reduce the thermal conductivity of the materials.     

轮胎硫化过程的有限元分析

开发了能够较准确地数值模拟轮胎硫化过程的有限元分析软件。该软件考虑了轮胎材料的非均质性、橡胶基复合材料传热性能的各向异性、轮胎硫化时橡胶材料伴有的反应生热以及轮胎硫化的实际加温历程。对某载重子午线轮胎的硫化过程进行的仿真计算得到的数值表明该有限元数值仿真软件有效、可靠。     

轮胎直压硫化工艺的有限元仿真

传统的蒸汽硫化机具有胶囊和蒸汽室,使用过热蒸汽加热轮胎使之硫化。蒸汽的传热效率低,能量浪费严重。由于蒸汽的放热冷凝,蒸汽室底部的温度低于蒸汽室顶部的温度,这导致轮胎的不均匀硫化。直压硫化则采用电磁加热方式,其产生的温度场均匀,局部区域温度具有可控性。其次直压硫化工艺用大小鼓瓦与轮胎直接接触传热的方式,其传热效率应该比蒸汽硫化工艺高。本文基于ABAQUS软件,编写HETVAL和UVARM子程序模拟实际硫化工艺得到255/30R22轮胎的温度场和硫化程度场,在相同硫化条件下比较两种工艺的硫化效果。结果表明直压硫化工艺的硫化效率大约提高了三分之一。     

地面高速轮胎复合材料生热专家系统的应用

介绍地面高速轮胎复合材料生热计算机专家系统。该系统在对不同规格、不同厂牌的轮胎进行大量测温试验主材料生热性能试验的基础上,利用轮胎材料生热性能和导热性能的研究结果,采用有限元计法计算轮胎各部件在各种使用条件下的温度场分布,并进一步研究了轮胎生热与气压,速度及负荷等使用条件之间的关系。应用该系统有利于各种使用条件的合理匹配,确保轮胎正常使用。     

滚动轮胎热分析研究进展

汽车安全、节能、环保己成为当今汽车工业发展的主题,这要求与之匹配的轮胎性能相应提高。汽车轮胎是由橡胶及橡胶基复合材料构成的,它是集材料、几何、边界接触非线性以及热状态于一体的复杂结构体,轮胎力学场与温度场的分析十分复杂。对轮胎生热机理、橡胶损耗因子、温度场测定的计算研究等进行了介绍,滚动轮胎热分析研究已成为了轮胎工作者广泛关注的课题,对于指导轮胎设计、车辆安全行驶等具有十分重要的现实、经济和社会意义。     

Thermal Properties of Copy Paper Sheets

The thermal conductivity and specific heat of paper are important in determining its response to heat pulses encountered in applications such as copying or digital printing. This work reports measurements of the thermal conductivity, contact resistance, and specific heat for a number of commercial copy paper sheets. The experimental setup was designed to measure transient and steady-state temperature distribution in stacks of paper sheets from which the thermal properties were determined. Steady-state measurements of the temperature difference were used to determine the thermal contact resistance and the thermal conductivity of the sheets. The specific heat was determined from the transient temperatures recorded during heat-up and cool-down periods. The thermal conductivity depends upon the sheet density, filler content, and nature of the fibers. It also showed a small increase with temperature of approximately 10^?4 W/(mK)/K. Models of thermal conductivity based on the resistance of the fibers and the fillers were developed. The thermal contact resistance increased with the surface roughness as measured by the Gurley permeability (referring to surface roughness). The specific heat of paper was dependent on its ash content.     

子午线轮胎11R22.5的硫化仿真分析

利用ABAQUS软件对子午线轮胎11R22.5进行硫化仿真分析,通过模型建立、材料参数及边界条件赋予等,建立起了仿真分析的硫化温度场和程度场云图。通过与轮胎硫化测温实验结果对比得到,各测温点仿真分析的硫化温度和硫化程度与实验结果基本吻合,验证了此分析方法的可行性。对硫化过程中的初始条件、边界条件及材料参数因素进行分析,得出轮胎初始温度、外温和胶囊的导热系数对轮胎的硫化程度影响较大。总体来说,目前初步建立起轮胎仿真的分析平台,并可为轮胎硫化工艺的优化提出理论指导。     

胶料热物性对微波加热硫化温度场的影响

采用闪光导热分析仪和差示扫描量热仪对异戊橡胶(IR)在硫化过程中的热物性参数进行测量,得出热导率和比热容随温度的变化规律。同时采用ANSYS有限元分析软件对IR进行三维建模,并对其微波加热硫化过程进行数值模拟,得到热导率和比热容恒定或随温度变化等4种情况下胶料内部的焦耳热密度分布和温度分布。结果表明,热导率变化对胶料温度分布影响不大,而比热容变化的影响较大。     

The use of drying experiments in the study of the effective thermal conductivity in a solid containing a multicomponent liquid mixture

The effective thermal conductivity of a porous solid containing multicomponent liquid mixtures has been studied. To achieve this, the liquid composition, liquid content and temperature distributions have been measured in a cylindrical sample dried by convection from the open upper side and heated by contact with a hot source at the bottom side. A quasi-steady state reached at high source temperatures permits to calculate the total heat flux from temperatures measured on the surface and the gas stream. The simulations performed and compared with experimental data made it possible to estimate the adjusting geometric parameter of Krischer's model for the effective thermal conductivity. The effective thermal conductivity has been widely studied for two-phase systems, mostly with regard to thermal insulation elements. The calculation of this transport parameter includes the contribution to heat transfer of the evaporation–diffusion–condensation mechanism undergone by the multicomponent mixture. The influence of liquid composition and temperature on the thermal conductivity due to the evaporation–diffusion–condensation mechanism and the effective thermal conductivity is described. The results reveal that in this case the resistance to heat transfer seems to correspond to a parallel arrangement between the phases.