Eee ou ll SECRET om 3 Project 3.1 - Difference in Effect of Long and Short = Capt R. E. Grubaugh — WADC Duration Blast Loadings on the Response of Structures The objective of Project 3.1 is to show the difference in effect of a long- duration positive-phase blast-loading pulse from a high yield weapon as compared to a lower yield or conventional kt weapon, on a drag-sensitive and semi-dragsensitive structure. It has been theorized that if an elasto-plastic structure could be idealized as a single degree of freedom mathematical model, the peak pressure criteria for estimating structural damage would necessarilybe modified in the case of a high yield weapon. Our second objective is to add to the body of information on loading and damage of prospective targets from a target analysis and weapons allocation standpoint® Our structures will be the same as those in Operation TEAPOT since this is a second portion of that experiment. They will be 40' by 40' and 40' by &80', light steel, industrial type structures. Our instrumentation will consist of 15 channels approximately per structure, which will include pressure-time curves, deflection and sheer in the columns, and acceleration time recordings - further, photography- one motion picture camera per structure, to give us a time history of deflection, The end product of our experiment should be a pressure-damage curve for the two cases or iso—- damage curves, Our operation plan involves only one problem since this is a passive type experiment. We wish to enter the area for a prolonged stay - approximately -five to seven days = as soon as the radiation level has subsided enough to allow this stay in the area, We expect to have approximately eight people in the area for a period from D=2 months to D42 weeks for shot Cherokee, Project 3.10 = Structures Instrumentation - Glenn L. Roark = BRL The object of Project 3.10 is to furnish, install, calibrate and to record instrumentation for Project 3.1. We also will record instrumentation for Pro ject 1.5 and will conduct a diffraction study of two of these man-made islands that Capt Grubaugh just explained to you. These islands will be of two sizes and will have a diffraction study on one small one and one large one. The purpose of this diffraction study is to substantiate model programs involving a structure of sanewhat the same shape as this island. Due to the fact that we don't know when the shot will go off in respect to tide, there's a good possibility that we'll have somewhere in the neighborhood of 6' front and sides all the way around the island; a question has arisen as.to how this will affect the wave form on the island. Since Project 3.1 is interested in this wave form,we are conducting this diffraction study to help them substantiate their informatio.