Optimal Design of Branch Distribution Network in Rural Drinking Water Safety Project

On the basis of the traditional linear programming model,this paper presents a optimal design mathematical model of gravity branch distribution network. Considering the coupling constraint, the model takes the length of main and subordinate pipe having standard diameter as decision variables. The minimum works investment is taken as objective variable, and the MATLAB is used to solve. There are a better result in the optimal design of branch distribution network with this method in the application cases, and which can provide a basis for the rural drinking water safety project.

Finite Element Modeling and Modal Analysis of Bolted Joints

In order to properly simulate bolted joints and make the numerical modes as accurate as possible, this paper is focused on modeling methods for dealing with bolt connection structures composed of two sheets. Six methods are presented to establish the FE models using different element types(8-node brick elements and 4-node shell elements) and different constraints (such as contact interaction and coupling constraint). The models are solved in ABAQUS software and natural frequencies and vibration shapes are obtained. Then, the experiments of bolt fastening structures are performed and FE simulation results are compared with the experimental ones. Moreover, the methods which agree well with the experiments are selected as the FE model of bolted connection. Finally, the element layers in the through-thickness direction are discussed. FE models built in this paper can reflect the real situation of bolted joints and provide significant reference to FE analysis for the complex system connected by bolts.

Asymptotic Modal Analysis of Structure Borne Noise in Cross Beams

The dynamic response (structure borne noise) of two cross beams intersecting perpendicularly to each other is studied for a point load applied vertically at an arbitrary location on one beam. The modal analysis technique is used to analyze the bending and torsional responses of the system of coupled beams. The modal equations of motion are derived from Lagrange’s equations with the coupling constraint at the beam intersection point included via Lagrange multipliers. For the limiting case of a large number of participating modes, an asymptotic modal analysis is performed resulting in simple estimates of the upper and lower bounds of the beam responses. These bound estimates are compared with the corresponding SEA results.