New Method for Calculating Aircraft Equivalent Single Vulnerable Area

A new method is proposed for calculating the aircraft equivalent single vulnerable area using Monte-Carlo simulation technique. The method simulates the kill events of single vulnerable components and multiply vulnerable components or redundant components to ＇Model of Filling Boxes with Balls＇, in which the area of each box is equal to the component＇s vulnerable area. By randomly and uniformly sampling the threat hit locations, the expected number of hits required to kill an aircraft can be given and the aircraft equivalent singly vulnerable area can be attained. Examples demonstrate the correctness and feasibility of the proposed method. Analysis show that the developed method overcomes two shortcomings of currently used methods. （1） It can calculate the equivalent single vulnerable area of aircraft with several sets of multiply vulnerable components, and （2） When the components of each multiple set have different vulnerable areas, the method also applies.

Investigation of cost-effectiveness of highway asphalt pavement maintenance treatments based on rutting development analysis

To investigate the cost-effectiveness of different maintenance treatments of highways in Jiangsu Province, the historical pavement maintenance records, traffic load information and pavement performance data in the pavement management system （PMS） are recorded and analyzed. Compared with the growth model, the linear model, the logarithm model and the exponential model, the cubic model has higher regression accuracy R2 and it can capture the sigmoid shape of the deterioration curve. So it is selected to simulate the pavement rotting development. The benefit over cost ratio is calculated to quantify the treatment cost- effectiveness. The analysis results show that thin hot mix asphalt （HMA） overlays and micro surfacing are more cost- effective than the. other two treatments on light and moderate traffic roads. Hot in-place recycling and thick HMA overlays have much longer service lives and greater cost-effectiveness under heavy or extra heavy traffic.

Free vibration of functionally graded sandwich plates in thermal environments

This paper presents an analytical solution for the free vibration of functionally graded material(FGM)sandwich plates in a thermal environment.An equivalentsingle‐layer(ESL)plate theory with four variables is used to obtain the solution.Two types of sandwich plates are examined in this study:one with FGM face sheets and a homogeneous core and the other with an FGM core and homogeneous face sheets.The governing equations of motion are derived based on Hamilton's principle and then solved using the Navier method.The results of natural frequencies of simply supported FGM sandwich plates are compared with the available solutions in the literature.The effects of volume fraction distribution,geometrical parameters,and temperature increments on the free vibration characteristics are discussed in detail.