永磁同步电动机变频器投切系统研究

介绍了两种永磁同步电动机变频器投切系统的原理,详述了变频器切换过程,对比分析了两种系统的不同点.并通过实例验证了其中一个方案,为多台永磁同步电动机系统的应用提供了理论和实践依据.     

纤维复合材料加固混凝土梁纯弯段保护层剥离应力近似计算

针对纤维复合材料 (FRP)加固混凝土梁纯弯段保护层剥离破坏情况 ,基于实用混凝土梁实验研究成果和有限元方法 ,提出一种过高估算剥离应力的方法。该方法表明 ,剥离应力不大。     

Double pull specimen more suitable for measuring bond-slip relationship of FRP-to-concrete interface

A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip (δ-τ) relationship of fiber reinforced polymer (FRP)-to-concrete interface more accurately. A finite element analysis (FEA) was performed for preliminarily evaluating the suitability of the proposed conceptual double pull specimen. Through the FEA, it was indicated that the FRP-to-concrete interface of the proposed conceptual specimen might subject to a much higher load level than that of the most commonly used simple shear specimen, showing a great potential for measuring δ-τ relationship more accurately. In the light of the conceptual specimen, a kind of "practical" double pull specimen was developed and proved to be more suitable for measuring δ-τ relationship through an exploratory experimental study with 20 specimens. Consequently, an experimental program with 10 double pull specimens was performed for measuring the ultimate slip δ_u which was difficult to capture by using the existing specimens. It is shown that the range of δ_u is 0.31-0.52 mm based on the test results. The suggestion for improving the measure method is also put forward.     

一种估算纤维布加固混凝土梁跨中保护层剥离应力的方法

提出一种过高估算纤维复合材料 (FRP)加固混凝土梁跨中保护层剥离应力的方法 ,供抗剥离设计参考。典型算例表明 ,剥离应力不大 ,进而推荐既安全又经济的由单向“—”型碳纤维 (CF)布和双向L型玻璃纤维 (GF)布混杂加固混凝土梁的设计方法     

绿色建筑规划中可再生能源建筑指标确定研究

分析了城市绿色建筑规划中可再生能源建筑指标确定的必要性,提出了地方可再生能源建筑应用规划指标确定的一般方法.依据该方法,给出了广东省Z市2013年～ 2020年间可再生能源建筑应用的规划指标.     

永磁同步电机极弧系数选取*

永磁同步电机的极弧系数对电机性能影响较大。结合有限元仿真软件,对8极48槽永磁同步电机选取不同的极弧系数,分析其对电机气隙磁密、空载感应电动势和电磁转矩的影响。通过对比分析,得到这种槽极配合下极弧系数的合适值。     

计算FRP加固RC梁跨中保护层剥离应力的新思路

指出对剥离块体进行有限元分析,准确计算纤维复合材料(FRP)加固钢筋混凝土(RC)梁跨中保护层剥离应力的困难,提出解决这一困难的新思路,说明按新思路计算得到的剥离应力更加接近实际情况。     

一种可降低建筑楼板L'nT,w值的超薄型隔声砂浆

计权标准化撞击声压级(L'nT,w)是绿色建筑评价中重点关注的指标,隔声砂浆可有效降低建筑楼板L'nT,w值.提出了一种厚度仅为10 mm的超薄型隔声砂浆解决方案,可降低隔声砂浆的施工难度,提高工程实用性.典型应用案例表明,超薄型隔声砂浆可以有效降低建筑楼板L'nT,w值,且隔声性能可以满足绿色建筑评价标准的要求.     

关于FRP加固钢筋混凝土梁跨中剥离应力计算方法的讨论

综述了几种FRP加固钢筋混凝土梁的跨中剥离应力的计算方法,说明对剥离块体进行有限元分析方法的优越性.