Hybrid material consisting of mechanoluminescent material and TiO2 photocatalyst

From the viewpoint of utilizing a mechanoluminescent (ML) material as a light source, the surface of the ML material should have the most effective photoreaction with the strongest photointensity from the ML material. A hybrid material that combines an ML material and a photoreactant material is a promising way of accomplishing this. This paper discusses a preparation method for a hybrid material consisting of the ML material and TiO₂ photocatalytic nanoparticles. By using the surface sol–gel method, we succeeded in immobilizing the TiO₂ photocatalytic nanoparticles on the surface of the ML material, thus preparing a hybrid material where the nanoparticles took over the original mechanoluminescence and photocatalysis activities.     

考虑余-废料资源回收的车间物料配送路径规划研究

针对离散制造生产过程中物料配送及余-废料资源回收效率低、成本高等问题,在分析车间物料流循环过程基础上结合物料配送时间窗限制,提出了物料配送和余-废料资源回收协同优化的物料再循环策略,并建立了以车间物料流总成本为目标的物料再循环路径规划模型。利用遗传算法在Matlab软件中对实例进行求解,验证了物料再循环策略应用于离散制造车间物料配送和余-废料资源回收的可行性和有效性。     

材料设计研究的3个视角

目的 从设计师、材料特性以及用户体验维度提出材料设计研究的3个视角.方法 采用文献梳理、理论阐述和案例分析的方法对材料设计研究进行系统性整理.结论 材料设计研究的视角包括设计师式的材料探究和材料思维、材料特性和科学选材策略、材料体验和材料驱动创新方法.3个视角有助于厘清材料设计研究的理论和方法,有助于从思维、材料以及体验3个层面构筑材料的研究体系,为未来的材料设计研究提供可行的实践和理论方向.     

材料的表情

材料是产品构成中的物质要素,而材料的表情是一种审美情感,所以对材料表情的合理使用关系到产品的审美功能的发挥,从3个方面进行讨论:材料与色彩的同构性,材料表情与形态、加工工艺的密切关系,材料表情的应用.从而说明设计师要抓住材料的表情、学会用材料进行思维的重要性,指出研究材料表情的意义.     

基于坐标变换的功能梯度材料空间映射建模研究

随着3D打印零件复杂性和多样性的日益增加,单一材质的零件已无法满足各类特殊性能要求,功能梯度材料零件逐渐成为快速成型制造行业的研究热点。为满足功能梯度材料的制造要求,提出了一种基于坐标变换的功能梯度材料空间映射建模方法,该方法的关键是将几何信息与材料信息有效结合。首先,采用单梯度源法、多梯度源法构建功能梯度材料模型的材料空间,在遇到交叉梯度源模型时利用特定的相交算子以一定的权重比进行材料分布计算。然后,在几何空间与材料空间结合的过程中,巧妙地通过坐标变换将材料空间与几何空间的坐标系重合,实现将材料空间映射至几何空间,从而得到带有材料信息的功能梯度材料模型。通过修改梯度源、材料分布函数以及坐标变换方法即可获得所需的功能梯度材料模型。利用Visual Studio 2019软件和OpenGL编程语言对实例模型进行可视化分析的结果表明,所提出的建模方法相比于大部分估值建模、非估值建模方法可大大缩短建模时间,从根本上解决了某些算法所造成的储存空间不足和建模过程繁琐等问题。基于坐标变换的功能梯度材料空间映射建模方法为增材制造行业提供了一种新的建模方法,具有良好的应用价值。     

牛顿插值算法在材料数据库开发中的应用

在介绍材料数据库的基础上，分析了材料数据库中材料某些信息的不完备。论述了牛顿插值算法的数学原理，并在实例中验证了其可行性，然后应用于材料数据库开发中。通过该方法，扩充了材料数据库的材料信息，提高了查询材料信息的速度，从而指导模具生产企业合理选材。     

基于离散元法的料门式给料器料门受力研究

目的研究料门式给料器工作中颗粒物料对料门的作用力,以便选择合适的驱动机构。方法对给料器结构进行合理简化后,利用离散元法借助PFC3D软件,仿真计算料门完全关闭时受颗粒物料的作用力;将料门及实现其转动的辅助机构合理简化为杆件机构,分析料门在几个关键位置所需的驱动力。结果颗粒物料对料门垂直方向的合力始终小于其自身的重力,而且随着颗粒物料高度的增加此现象会变得更加明显;料门受到颗粒物料的正压力和切向静摩擦力,随着料斗内料位高度的增加最初呈线性增大,后转为非线性并趋于极限值,而且变化过程与料斗结构也有一定关系;料门在完全关闭状态打开料门所需的摆动臂驱动力约为115 N,在精给料时维持精给料位置所需限位臂驱动气缸的推力约为553 N。结论设计料门式给料器时只需计算一定料位高度的料门受力,超过此高度后物料继续增多时料门受力基本不变;使用的料门式给料器采用的气缸驱动力足够大,能够保证正常工作。     

羰基铁室温硫化硅橡胶复合材料的吸波性能EI北大核心CSCD

为制备兼具力学性能和电磁吸收性能的高带宽吸波材料,采用纳米粒子改性及物理共混法设计制备一种以聚二甲基硅氧烷为基体的羰基铁室温硫化硅橡胶复合材料,系统地分析了该复合材料的力学性能与吸波性能。结果表明:当白炭黑质量分数为3%时,复合材料的综合力学性能最佳,便于材料加工;该复合材料为磁损耗型吸波材料,材料的衰减常数随羰基铁含量和频率呈正相关。根据仿真计算得出,在2~18 GHz下,随着复合材料厚度和羰基铁含量增加,电磁波的吸收峰都逐渐向低频移动,当复合材料的厚度为1.5 mm且羰基铁质量分数为75%时,吸波材料有效吸收带宽可以达到9.07 GHz,占目标带宽56.68%。在实际应用中可根据应用场景需求来优化配方和控制材料厚度,达到最佳的吸波效果。     

A comparison of different approaches in the multi-scale computation of configurational forces

In the present work the FE² scheme is extended towards the homogenization of material quantities like the Eshelby stress and material node point forces. Therefore, in contrast to standard computational homogenization schemes volume forces on the micro-and on the macro-level have to be taken into account which emerge in the material motion problem due to inhomogeneities in the material. Different approaches in the determination of the material stresses are compared and it is shown that the direct calculation of the material stresses in terms of averaged material quantities requires an internal extra term to fulfill the energy consistency represented by a Hill-Mandel type condition. Furthermore, two approaches based on the average of the material two-point stress and the Eshelby stress are compared which require a further scale-transition which is performed within a postprocessing step. The influence of different micro-structures onto the macroscopic material quantities is studied within numerical examples.     

材料结构状态集合分析理论

材料的结构性具有普遍性,材料的结构性研究是目前这一领域的研究难点和重点问题。材料结构状态集合分析理论是研究材料结构性问题的一种新的方法。材料结构状态集合分析理论是以材料结构的状态集合为研究对象,以材料的微结构元集合为基础,通过对材料微结构元配分函数的分析,建立起材料宏观层面上的材料结构状态集合函数方程,得到材料的整体宏观性能描述方法。根据对材料结构的宏观强度、材料结构的刚度和材料几何状态的变化,建立了材料结构状态集合函数的控制方程;通过材料微结构元集合的分布状态分析,建立了材料不同结构状态下的微结构元的配分函数方程;在对微结构元组构关系分析的基础上,建立了微结构元的具体分析方法和宏观参数之间的关系;讨论了材料结构状态集合分析理论下的若干理论问题及今后需要做的工作。     

Damage mechanics models of ductile crack growth in welded specimens

Two-dimensional, plane strain, finite element analyses of strength-mismatched welded joints have been performed using the modified boundary layer formulation. The welds were idealized as two-material joints with the material interface running parallel to the crack, which was embedded in the weld material. The Rousselier ductile damage model was employed within the weld material to simulate crack extension due to the growth and coalescence of microvoids. By analysing models with different levels of material mismatching, weld dimensions and applied T -stress levels, it was possible to analyse the effects of crack tip constraint due to both material mismatching and specimen geometry on the fracture resistance of the weld material.
The results show that material strength overmatching (where the weld material is stronger than the base material) reduces the level of constraint ahead of the crack, which can increase the resistance to fracture of the weld material. Conversely, material strength undermatching increases crack tip constraint, reducing the fracture resistance of the joint. By employing estimates for the crack tip constraint levels, Q _M , based on the applied load, level of material mismatching and weld region thickness, it has been possible to 'order' the J– resistance curves of overmatched joints by generating a family of J–Q _M loci which describe the effects of constraint on the fracture resistance of the weld material. However, it is shown that the Q _M-stress parameter is not capable of describing the effect of material strength undermatching on the fracture resistance of a joint, which can be much lower than that obtained from a high-constraint homogeneous specimen of weld material.     

船舶内部物流转运系统仿真

由于船舶内部物流转运系统输送路径复杂,物料分拆的环节多,很难建立数学模型对整个物流系统进行全面的描述或者对物流系统中运动的货物进行实时的跟踪,本文采用系统仿真技术验证船舶内部转运系统设计方案,通过系统仿真确定系统的瓶颈和转运能力.基于仿真分析结果,优化局部转运传输策略,改进了船舶内部转运系统的配置方案,提高了系统的整体转运能力.     

Flexible polymeric rib waveguide with self-align couplers system

The authors report a polymeric based rib waveguide with U shape self-align fiber couplers system using a simple micromolding process with SU8 as a molding material and polydimethysiloxane as a waveguide material. The material is used for its good optical transparency, low surface tension, biocompatibility, and durability. Furthermore, the material is highly formable. This unique fabrication molding technique provides a means of keeping the material and manufacturing costs to a minimum. The self-align fiber couplers system also proves a fast and simple means of light coupling. The flexible nature of the waveguide material makes this process ideal for a potential wearable optical sensor.     

选材系统的设计与实现

介绍一个基于材料科学数据库的选材系统。该系统按照开放性的原则设计，将材料科学数据分为三大部分：仅与材料成分有关的基本材料数据，材料加工和应用过程中产生的材料加工工艺和性能数据，材料产品的生产供应等商业信息。     

Einsatz des Ritzpendels zur Quantifizierung des Verschleißverhaltens bei der Bearbeitung von Naturstein

Use of a Scratch Pendulum for Quantification of the Abrasive Behaviour in Machining Stones The machining of natural stones is one of the most demanding applications of today´s cutting technique. Modern stone processing is based on grinding and it is usually done with diamond based tools. The achievable material removal rate is process dependant and mainly determined by tool speed and infeed. The tool durability depends on the adjustment of the parameters to the wear resistance of the processed material. This resistance is a material characteristic value. Using a scratch pendulum, it is possible to determine the energy needed to create a defined scratch and relate it to the induced material loss and the chipped material volume. The analysis provides a value which, after verification by industrial production data, can be seen as characteristic for the material. It therefore enables the quantification of a material dependant scratch resistance.     

材料数据库系统在选材评价中的综合应用研究

基于材料数据库的选材评价,可以充分发挥数据库海量存贮能力、强大的检索功能与计算机的超级计算能力,使待评价材料的筛选和大量数据初始化处理与模型计算等评价的繁琐复杂过程变得快捷、准确、简便和智能。在构建材料数据库系统的基础上,开发出材料适用性评价方法功能模块,实现了基于材料数据库的计算机辅助选材评价,在材料数据库系统向智能化技术发展的方向上进行了有益的尝试。通过评价得到的量化结果,直观反映出性能相近或各有优劣的选材方案的差异,减少了仅凭经验甄别选材方案时的主观性或盲目性。     

A circular tube or bar of cylindrically anisotropic magnetoelectroelastic material under pressuring loading

A cylindrically anisotropic magnetoelectroelastic material is a special inhomogeneous anisotropic magnetoelectroelastic material. The constitutive law for any material point is the same when it is referred to a cylindrical coordinate system. An example of cylindrically anisotropic magnetoelectroelastic material is composite made of cylindrically anisotropic piezoelectric/piezomagnetic materials. In this paper an exact solution is derived for the two-dimensional problem of a circular tube or bar of cylindrically anisotropic magnetoelectroelastic material under pressuring loading by applying the Stroh formalism for a cylindrical coordinate system. The explicit expressions for the extended displacement vector and the extended traction vectors are presented. As encountered in the cases of elastic material and piezoelectric material, the stresses, electric fields, and magnetic fields at the axis of a circular rod may be infinite when the rod is subjected to a radial pressure. The existence of the singular stresses is also verified by our calculations for some magnetoelectroelastic materials.     

基于质感要素的产品材质意象设计研究

目的为了探讨产品材质意象设计的有效方法,研究利用质感要素来构建材质意象评价体系。方法利用色彩理论、主成分分析法等方法,确定产品色彩、材料、表面处理工艺的质感要素、质感要素评价等级和质感要素评价系数。利用质感要素定量描述确定材质、质感要素、材质意象的数学表达式,并构建三者之间的关系模型。结果以水杯为例,利用最小二乘法确定水杯材质意象评价模型。经验证,水杯材质意象评价模型的准确率为80%。结论质感要素评价等级、质感要素评价系数为材质意象设计提供了参数化方法。产品材质意象关系模型较好地反映了材质、质感要素、材质意象之间的内在关系。利用提出的材质意象设计方法,可计算任意产品的材质意象值,为产品材质意象设计提供理论指导。     

生物质碳源制备锂离子电池正极材料Na2MnPO4F/C及其电化学性能研究

本文以甘蔗渣作为生物质碳源制备Na2MnPO4F/C正极材料。通过球磨法及原位热解法制备Na2MnPO4F/C正极材料,利用拉曼光谱对正极材料制备条件进行表征分析,得出Na2MnPO4F/C最佳制备条件为碳源用量15%、煅烧温度600℃。利用XRD、SEM、EDS、电化学测量技术等手段对材料进行表征分析,结果表明,材料结晶性良好,碳材料很好地包覆在Na2MnPO4F聚氟阴离子材料表面,并且不影响材料结构。组装成纽扣电池,进行电化学性能测试。结果表明Na2MnPO4F/C材料电化学性能优于Na2MnPO4F材料,在0.1C下,Na2MnPO4F/C材料首圈放电比容量为8.71 m Ah/g,而Na2MnPO4F材料首圈放电比容量为1.94 m Ah/g,通过原位热解法进行碳包覆能有效的提高材料的电子电导性,增加容量。     

Application of an orthotropy rescaling method to edge cracks and kinked cracks in orthotropic two-dimensional solids

Oblique edge cracks and kinked cracks in orthotropic materials with inclined principal material directions under inplane loadings are investigated. The Stroh formalism is modified by introducing new complex functions, which recovers a classical solution for a degenerate orthotropic material with multiple characteristic roots. An orthotropy rescaling technique is presented based on the modified Stroh formalism. Stress intensity factors for edge cracks as well as kinked cracks are obtained in terms of solutions for a material with cubic symmetry by applying the orthotropy rescaling method. Explicit expressions of the stress intensity factors for a degenerate orthotropic material are obtained in terms of solutions for an isotropic material. The effects of orthotropic parameter, material orientation, and crack angle on the stress intensity factors for the degenerate orthotropic material are discussed. The stress intensity factors for cubic symmetry materials are calculated from finite element analyses, which can be used to evaluate the stress intensity factors for orthotropic materials. The energy release rate for the kinked crack in an orthotropic material is also obtained.