建筑塑料型材生产中如何采用研磨工艺

研磨是化工、食品和印刷等生产中一种原料预处理的方法,磨研是将生产中大颗粒的粉状原料通过强制磨擦研细为小颗粒原料,以符合生产的要求。目前,已有许多塑料生产厂采用此工艺。 1.采用研磨工艺的依据生产塑料型材以聚氯乙烯(PVC)树脂为主要原料。PVC是热敏性塑料,加工温度接近分解温度,且加工流动性差。因此,在加工中需加入稳定剂、增塑剂等助剂以改善其加工性能。在生产过程中,型材表面常出现白色或浅黄色的杂质,这些杂质一方面影响作为建筑装饰材料的塑料型材的装饰效     

如何增强PVC塑料型材的抗冲击性能

PVC塑料型材因具有耐腐蚀、耐老化等优良性能而得以广泛应用,但它又是一种坚硬而脆的材料,抗冲击强度较低,加工性能不佳。本文从原材料、混料、设备与模具、配方、加工工艺5个方面对其进行改进,以获得稳定、优良的抗冲击性能。     

浅析铝合金门窗辅助型材配合问题

随着我国经济腾飞,铝合金门窗行业的不断发展,门窗产品日新月异,功能要求越来越高。铝合金型材作为铝门窗产品的主要材料,其几何尺寸精度要求也越来越严格。在日常门窗设计过程中,往往强调型材生产的精度,而忽视了型材设计及门窗加工工艺调整对门窗型材配合的影响。下面针对铝合金角码及压线在门窗制作中的配合问题进行浅析。     

63平开系列铝塑复合三玻型材

哈尔滨开发成功的63平开系列铝塑复合三玻型材,是采用专用设备将铝合金型材与PVC塑料型材,经特殊的加工工艺在机械力的作用下,复合成为一个整体。该复合材料内外两侧为铝合金型材,中间夹以PVC塑料型材,良好的隔热性能通过在铝合金型材中插入低导热性能的PVC塑料型材得到。采用该材料生产的63平开系列铝塑复合型材门窗具 有高强度复合、等压密封、三玻或双玻通用、欧洲标准五金件槽口等特性,属于新型节能门窗,建筑节能效果显著。采用63平开系列铝塑复合型材制作的门窗抗风压性、气密性、水密性、保温性、隔声性能、…     

断桥铝型材内填充聚氨酯的工艺及产品性能研究

研制具有优良隔热与力学性能的铝合金型材对建筑节能与安全有重要意义.提出了一种在穿条式断桥铝型材中间填充硬质聚氨酯泡沫的方法,通过试验对其主要制备工艺参数进行了研究,并且分析了此种型材的性能.结果表明,型材温度、型材长度、原料温度、型材放置方式等对型材内聚氨酯的发泡效果都有较大影响,该型材与未填充硬质聚氨酯泡沫的相比,热阻提高了63.64％,抗剪强度提高了23.44％.     

影响PVC门窗焊角强度的因素

焊角强度的降低直接影响PVC门窗的加工组装质量，本文主要从型材质量、焊接工艺参数及焊缝清理等三方面论述对PVC门窗焊角强度的影响。     

63平开系列铝塑复合三玻型材在哈尔滨研制成功

一种新型建筑门窗材料铝塑复合型材在哈尔滨研制成功。它是采用专用设备将两种不同的材料:铝合金型材与PVC塑料型材,经特殊的加工工艺在机械力的用下,复合成为一个整体。该复合材料内外两侧为铝合金型材,中间夹以PVC塑料型材,通过在铝合金型材中插入低导热性能的PVC塑料型材使该复合材料具有良好的隔热性能。采用这一新材料生产的63平开系列铝塑复合型材门窗具有高强度复合、等压密封、三玻或双玻通用、欧标五金件槽口等特性,属于新型节能门窗。该产品符合国家建设部提出的节能要求,建筑节能效果显著。63平开系列铝塑复合三玻型材在哈尔…     

如何提高塑料异型材冲击强度

系统介绍了影响ＰＶＣ塑料异型材低温冲击性能的因素,包括型材配方、混合、挤出设备、模具及成型工艺     

不锈钢门窗现状与发展研究

我国不锈钢门窗生产起步较晚，早期产品的截面结构基本取形于铝窗和钢窗的型材。对不锈钢材质的优点不能充分利用与发挥，反而带来了不锈钢门窗型材加工的难度、成窗外观不挺拔、色彩不丰富，使不锈钢窗处境窘迫。本文分析了不锈钢门窗型材截面、加工设备现状。介绍新改进型不锈钢窗用9截面型材的结构特点、型材加工的辊模设计、转速与间距调整对产品质量的影响、不锈钢窗加工专用中型机组的特点。提出了不锈钢门窗的发展方向。     

浅谈宝硕型材的加工工艺

本文详细介绍了有关宝硕型材在储存、运输、下料、焊接、工艺孔加工等方面的具体工艺要求。     

Numerical evaluation of wind effects on a tall steel building by CFD

A comprehensive numerical study of wind effects on the Commonwealth Advisory Aeronautical Council (CAARC) standard tall building is presented in this paper. The techniques of Computational Fluid Dynamics (CFD), such as Large Eddy Simulation (LES), Reynolds Averaged Navier-Stokes Equations (RANS) Model etc., were adopted in this study to predict wind loads on and wind flows around the building. The main objective of this study is to explore an effective and reliable approach for evaluation of wind effects on tall buildings by CFD techniques. The computed results were compared with extensive experimental data which were obtained at seven wind tunnels. The reasons to cause the discrepancies of the numerical predictions and experimental results were identified and discussed. It was found through the comparison that the LES with a dynamic subgrid-scale (SGS) model can give satisfactory predictions for mean and dynamic wind loads on the tall building, while the RANS model with modifications can yield encouraging results in most cases and has the advantage of providing rapid solutions. Furthermore, it was observed that typical features of the flow fields around such a surface-mounted bluff body standing in atmospheric boundary layers can be captured numerically. It was found that the velocity profile of the approaching wind flow mainly influences the mean pressure coefficients on the building and the incident turbulence intensity profile has a significant effect on the fluctuating wind forces. Therefore, it is necessary to correctly simulate both the incident wind velocity profile and turbulence intensity profile in CFD computations to accurately predict wind effects on tall buildings. The recommended CFD techniques and associated numerical treatments provide an effective way for designers to assess wind effects on a tall building and the need for a detailed wind tunnel test.     

双曲冷却塔结构规范风荷载标准值对比

以参数分析为基础,对中、英、德双曲冷却塔结构设计规范风荷载标准值的取值原则和计算思路进行了对比,研究了基本风速、风剖面、内外表面静风风压环向分布、脉动效应系数、干扰效应系数等参数的取值和相互影响,并介绍了中、英、德双曲冷却塔设计规范与其荷载规范相关条款的差异;以3座不同高度的双曲冷却塔为例,对比分析了中、英、德规范的脉动效应系数取值,并对1座双曲冷却塔分别采用中、英、德规范计算等效风荷载标准值及其荷载效应。结果表明:受设计基本风压剖面和脉动效应系数控制,中、德规范的荷载标准值剖面较为接近,但明显小于英国规范;受荷载标准值剖面和环向压力分布影响,塔筒中下部区域子午向拉力和环向弯矩的极值分别对应于英、德规范,而喉部位置英国规范得到的子午向拉力和环向弯矩的极值分别为中、德规范的1.4倍和1.1倍。     

分离式公铁双层桥面桥梁-列车-风屏障系统气动效应风洞试验研究

为探究侧风作用下分离式公铁双层桥面桥梁上、下桥面间气动干扰效应对列车气动效应的影响,在无风屏障和设置风屏障两种情况下,分别针对单独铁路桥和标准间隔高度下的公铁双层桥面桥梁,通过大比例尺节段模型风洞试验测试了列车的气动力系数以及铁路桥面轨道上方的风速剖面变化规律。为了进一步探究公铁双层桥面间隔高度对列车气动效应的影响,测试了多种间隔高度下列车气动力系数以及铁路桥面轨道上方的风速剖面变化规律。结果表明,公铁双层桥面间气动干扰效应对列车气动效应有一定的影响,间隔高度的改变会引起铁路桥面风速剖面以及列车气动力系数的变化,对比分析可知,无风屏障时间隔高度仅需满足铁路桥梁基本建筑限界即可,设置风屏障后,当间隔高度≥15m时,铁路桥面风速剖面以及迎风侧轨道处列车气动力变化趋于平缓。     

A quantitative approach to the assessment of the environmental impact of building materials

The materials from which a building is constructed make a significant contribution to its overall impact on the environment. This impact is felt in a number of ways; locally, through the effects of activities such as quarrying; globally, as a result of carbon dioxide released by using energy used to manufacture the materials; and internally, in the effects on the health of the occupants of the building.

Some of these effects are easier to measure than others, and comparisons between the seriousness of the different effects are difficult to make. It therefore seems unreasonable to attempt to devise a single figure of merit for the overall environmental impact of a building; what is needed is a profile which gathers together a range of indicators, but allows them to remain separate. This article describes the development of such an environmental profile which can be used as a design aid, and illustrates its use with a case study of a typical British house.     

物探技术在水下管线探测中的应用

简述了水域磁测、浅层剖面、侧扫声呐等物探方法的原理及工作方法,通过工程物探实例,展示了这些物探方法在水下管线探测中的应用效果,并简要分析了这几种方法的局限性.根据物探方法的适用性,合理地选择将要实施的方法,取得了满意的效果.     

撞击型触发器对帽形薄壁截面轴向挤压影响的数值分析

主要介绍了触发器的设计和性能。为了分析撞击型触发器的几何特征对于轴向冲击荷载作用下耗能构件的抗挤压性能的影响,对其进行数值分析。该耗能构件由一个平盖加一个帽形顶部剖面构成。将触发器视为一个在帽形剖面上具有半圆形横截面的突起物,采用有限元软件LS-DYNA模拟所有的挤压作用。结果显示：在挤压力峰值和轴向冲击荷载作用下的构件耗能能力上,触发器的引入非常有效。同时发现,通过改变触发器的位置和几何尺寸,可以控制构件的挤压响应。     

体外预应力结构弹性内力分析

约束次内力法是求解预应力超静定结构内力的一种方法。根据约束次内力法的原理 ,针对体外预应力加固工程的实际需要 ,直接给出数种预应力线型布置在三种约束下的约束次内力公式 ,并基于该方法讨论了力筋线型对体外预应力连续梁的预应力效果的影响     

前期建筑策划对房地产项目的经济性影响分析

本文介绍了房地产项目概况、周边项目信息解读、总体规划建议、出入口及道路规划设置、车位规划建议、建筑单体、建筑风格、景观规划等方面内容,分析了建筑策划对房地产项目的经济影性响,剖析了建筑策划的重要性和必要性。     

Effect of atmospheric temperature and droplet size variation on ice accretion of wind turbine blades

A numerical study of ice accretion and the resultant flow field characteristics of a 5 MW pitch controlled wind turbine blade profile (NACA 64618) have been carried out to understand the effects that atmospheric temperature and droplet size variations have on the rate and shape of ice growth. Resultant aerodynamic characteristics of the blade profile were analysed at different angles of attack ranging from −10° to +20°. Results show an increase in the ice growth with the increase of droplet size; whereas change in atmospheric temperature significantly affects the shape of accreted ice. Streamlined ice shapes were observed for low temperatures, whereas horn shape ice accretion was found at higher temperatures. Results show that for the iced blade profiles, changes in the aerodynamic characteristics are least prominent for the case of rime ice as compared to glaze ice.     

Effects of bolt profile and grout mixture on shearing behaviors of bolt-grout interface

Shearing behavior and failure mechanism of bolt-grout interface are of great significance for load transfer capacity and design of rock bolting system.In this paper,direct shear tests on bolt-grout interfaces under constant normal load(CNL) conditions were conducted to investigate the effects of bolt profile(i.e.rib spacing and rib height) and grout mixture on the bolt-grout interface in terms of mechanical behaviors and failure modes.Test results showed that the peak shear strength and the deformation capacity of the bolt-grout interface are highly dependent on the bolt profile and grout mixture,suggesting that bolt performances can be optimized,which were unfortunately ignored in the previous studies.A new interface failure mode,i.e.'sheared-crush' mode,was proposed,which was characterized by progressive crush failure of the grout asperities between steel ribs during shearing.It was shown that the interface failure mode mainly depends on the normal stress level and rib spacing,compared with the rib height and grout mixture for the range of tested parameters in this study.