Frequency Analysis of Functionally Graded Curved Pipes Conveying Fluid
The curved pipe made of functionally graded material conveying fluid is considered and the in-plane free vibration frequency of the resulting composite pipe is investigated. The material properties are assumed to distribute continuously along the pipe wall thickness according to a power law and the effective mass, flexural rigidity, and mass ratio are used in the governing equations. The natural frequencies are derived numerically by applying the modified inextensible theory. The lowest four natural frequencies are studied via the complex mode method, the validity of which is demonstrated by comparing the results with those in available literatures. A parametric sensitivity study is conducted by numerical examples and the results obtained reveal the significant effects of material distribution gradient index, flow velocity, fluid density, and opening angle on the natural frequencies of the FGM curved pipes conveying fluid.
We consider some routing criterions for connections with QoS requirements in the Internet, which support QoS guarantees for both the services and networks. First we investigate the path consumption, and give the definition of the path consumption function (PCF). Then we observe the path selection's influence on the link residual bandwidth, we find that letting the narrowband connection choose those links with small residual bandwidth can increase the admission probability of the broadband ones. We define the bandwidth fragmentation function (BFF) for connections which reflects this influence. After that we give the definition of the network efficiency function (NEF) for the network performance measure. A QoS routing scheme and some simulation results are given. We conclude with a summary and with directions for future work.