RESEARCH ON EVALUATION FOR AN ORIGINAL ENGINEERING WORKING MEASURE AGAINST TO THE "MUTISITE-CRACKING" OF SEAMS BETWEEN A PANEL AND ANOTHER PANEL FASTENED BY RIVETSLINE

日航“巨型客机”的随行人员和发生在夏威夷的随行人员记忆犹新。这些腐蚀是由于一块板材和另一块用铆钉线紧固的板材之间的“多点开裂”造成的。这些知情人士给了我们非常严重的震惊，意味着反对加压飞机机身破裂的“故障安全神话”彻底被打破了。因此，针对“多点开裂”提出新的工程措施是非常重要的。本研究的目的是验证首席调查员提出的针对“多点开裂”的新的工程措施的有效性。该方案的要点是利用混凝土搬运领域中非常流行的预应力技术，使机身的火焰和纵梁更努力地工作，确保对加压机身开裂的“失效安全”。为了验证该方案的有效性，手工制作了一台计算机控制的拉动式疲劳试验机。在试件出现裂纹后，利用超声波传声器、超声波测音仪和彩色打印机组成的声分析系统对每个试件进行超声波声发射测量，由于试件的尺寸太小，试件所用材料(普通铝)的硬度不足，没有达到预期的效果。同时，为了验证该方案的有效性，还进行了光弹实验，得到了预期的结果。

The acsident of JAL's "jumbo-plane" and the acsident occurred in HAWAII are fresh in our memory. These acsidents are caused by the "multisite-cracking" of seeam between a panel and another panel fastened with rivetsline. These acsidents had given us very serious shock for the meaning that the "failsafety-mythology" against to the cracking of pressurized airplane's body was broken thoroughly. So, getting of new engineering working measure against to the "multisite-cracking" is very important matter.The pupose of this research is to corroborate the validity of new engineering working measure against to this "multisite-cracking which have been proposed by head investigator. The gist of this proposal is, by using the prestressing technique which is very popular one in the concrete handling field, to make flames and stringers of the airplane's body work onestep harder and ensure the "failsafety" against to the cracking of pressurized airplane's body.To corroborate the validity of this proposal, a computer controled pulling type weariness testing machine was hand made. After the cracks had broken out on the test pieces, ultrasonic sound emission was measured by the sound analyzing system composed of ultrasonic microphon, ultrasonic sonagrph and color printer, on each experiment.Cause by the dimension of testing macine was too small, and by the stiffnes of material (normal aluminum) used for the test pieces was insufficient, expected result was not obtained.On the other hand, samely to corroborate the validity of the proposal, photoelasitic experiments has been executed.On this way, we get prospectfull result.