报告人：陈巩

美国德克萨斯农工大学Chen  Goong教授，主要从事分布参数系统控制理论与科学计算的研究。

主办单位：数学科学学院

 

报告一：

报告题目: Aircraft Structures Safety Design andTests

时间：2019年10月9日下午2:30

地点：汇贤楼123教室

 

报告摘要

Thecrashworthiness and survivability of aircraft totally depends on The dynamicbehavior of aircraft structures. This type of study first began with DYCAST(Dynamic Crash Analysis of Structures) Program at NASA Langley Research Centerin Virginia, USA. The basic test consists of the vertical drop of a section ofa section of passenger aircraft and then  determines the associateddamage.

Inthis talk, we give a systematized approach to the computer modeling of thevertical drop test by building a model with passenger dummies, seats, floor,stations, stringers, struts, fuselage skin, and seatbelts. We perform the droptest by first validating computer solutions, and the let the fuselage sectionhit the ground with pitch, roll, and on uneven grounds. We also consider when thefuselage consists of two sections.

Ourcomputer modeling will improve the designs of the safety of future airliners,save testing cost, and help develop other aviation products.

报告二：

报告题目: Implosion of the Argentinian SubmarineSan Juan S-42 Undersea: Study and Simulation

时间：2019年10月10日下午3:00

地点：汇贤楼121教室

 

报告摘要

ArgentinianSubmarine ARA San Juan S-42 was a TR-1700-class

diesel-electric submarine inservice with the Submarine Force of the Argentine Navy from 1986 to 2017. Itwas built in West Germany and entered service on 19 November 1985. But on 15November 2017, San Juan went missing during a routine patrol in the SouthAtlantic off the coast of Argentina, believed to have suffered an electrical malfunction.It was recently discovered in November 2018 that the submarine has imploded andits wreckage is located in a depth of 907 meter in the Atlantic Ocean.

Inthis talk, we will first describe the interesting and important phenomenon ofimplosion. The examples and videos from material science, civil engineering,and astronomy will be given.

Thenwe show the bifurcation patterns and then how to use the powerful softwareLS-DYNA to model the implosion phenomenon. We show how the submarine is crushedby the water pressure in deep ocean.

Ourwork is capable of capturing certain important patterns of implosion bycomparisons with benchmarks. The work shows dynamically how a submarineimplodes in deep ocean. We can use the large-scale computation to help thedesigns of submarines to improve their crashworthiness and survivability of thecraft.

Thework is supported in part by Qatar National ResearchFund NPRPGrant #9-166-1-031

 

报告三：

报告题目: Estimating the Sharpest Rates ofExponential Decay of Damping Mechanisms for Vibrating Structures

时间：2019年10月11日上午10:30

地点：汇贤楼122教室

 

报告摘要

The stabilizationof vibrations is an important topic in control system design. In this technicaltalk, the speaker will derive the sharpest bound for several types ofdistributed and/or boundary damping for vibrating membranes, beams and strings.ONe can see that such a sharp bound usually happens when the PDE system ischanging from under damping to over damping.