HiuM-, C.E., and Howo, R,M., "Application of Ihe 

 Eli'i-lrxmir Difforontial Analyzer Lo the Oscillation of Beams, 

 Includinf; Shear and Rolarj' Inertia," ASME, Applied Mech- 

 anics Division, September 1953j 



Jasper, N.H,, "A Design Approach to the Problem of 

 I'rilioal tthirling Speeds of Shaft-Disk Systems," DTMB 

 Report S9l), December 1954, 



Several methods for computing the natural whirling frequencies of 

 propeller-shaft systems are presented and discussed. Computed and 

 experiinentally determined natural frequencies are compared. 



Jasper, Norman H,, ".\ Theoretical and Experimental 

 Study of Propeller-Shaft Failures," DTMB Report 808, 

 Augii.st 19r..-!, 



This report presents a detailed study of the stresses in the tail- 

 shall of a T2-SE-A3 tanker of the MISSION type, including an analysis 

 of the causes of tailshaft failure encountered in these as well as in 

 Liberty ships and other ships of similar type. Emphasis is placed on 

 the effects of a whirling type of flexural vibration on the stresses and 

 motions of the shaft. One of the principal conclusions is that the shaft 

 failures are due to a lack of endurance strength of the shaft as designed 

 and built, and not due to a serious lack of endurance strength of the 

 shafting material itself. 



Jasper, N.H., ".A Theoretical Approach to the Problem 

 of Critical Whirling Speeds of Shaft-Disk Systems," DTMB 

 Report s:2V, December 1954. 



In this report a number of theoretical methods are derived for 

 computing the natural frequencies of whirling vibration of shaft-disk 

 systems including the consideration rotatory inertia, gyroscopic pre- 

 cession, and flexibility of shaft supports, as well as lumped and dis- 

 tributed masses. 



Jasper, N.H,, "Dynamic Loading of a Motor Torpedo 

 Boat (VP-UO) during High-Speed Operation in Rough 

 Water," DTMB Report C-175, September 1949. (Declassified) 



Vibrational acceleration, stress, and hull pressure measurements 

 are given for YP-110. 



Ja-^per, N.H., "Service Stresses and Motions of the 

 £.•^.-^0 ASHE\ ILLE, a T-2 Tanker, Including a Statistical 

 Anal\sis of Experimental Data," DTMB Report 960, 

 September 1955, 



Stresses amidships as well as pitching and heaving accelerations 

 were measured. Analysis indicates that the dynamic stress variations 

 associated with the ship's motion in waves will rarely exceed 12.000 

 psi peak-to-peak. The maximum stress variation due to changes in 

 temperature (excluding stress concentrations) was about 11,000 psi. 



Ja-per, N.H,, "Statistical Approach to Longitudinal 

 Strength De-ign of Ships," American Society of Naval 

 Engineer-, pp 565-573, Augu.st 19.50, 



This paper examines the present status of the problem of 

 ■Longitudinal strength of ships.' and presents a program of study of 

 the strength requirements. 



Jasper, N.H., "Statistical Distribution Patterns of 

 Ocean Waves and of Wave-Induced Ship Stresses and 

 Motions, with Engineering Applications," Trans, SNAME, 

 Vol. 64, 1956. Also DTMB Report 921, October 1957, 



This research attempts to show that by utilization of statistical 

 methods, it is possible to describe and predict service conditions for 

 ships in an orderly and relatively simple manner despite the general 

 complexities of the prtjblem. Wave-induced motions and stresses in 

 ships obtained under a wide range of operating conditons are presented 

 for seven different ships, 



Jasper, N.H,, "Structural Vibration Problems of Ships- 

 A Study of the DD692 Class of Destroyers," DTMB Report 

 C-36, February 1960. (Declassified) 



An investigation was made to detennine the sensitiyity of this 

 class to first order unbalanced forces. The long light hull was found 

 to be lacking in torsional and flexural rigidity compared to other ship 

 types. It was recommended that diagonal stiffeners be installed in the 

 hull girder and that the specifications for straightness and balance of 

 shafting be revised. 



Jasper, N.H., "Vibration Generator Survey of the 

 USS NIAGARA," DTMB Report 699, 1949. 



Five modes of vertical vibration, three athwartship, and one 

 torsional were determined by using a vibration generator. The experi- 

 mental natural frequencies were compared with calculated values. 

 Values of damping are calculated based on the experimental data. 



Jasper, Norman H., "Vibration Measurements Maae 

 11 August 1948 on the USS ODAX (SS 484)," DTMB Report 

 C-170, January 1949. (Declassified) 



Underway vibrations are given for both surfaced and submerged 

 conditions of SS 484. also vibration measurements recorded during time 

 that ship was excited by firing water slugs from Torpedo Tube No, 7. 



Jasper, N.H., "Vibration Survey of the USS MIDWAY 

 (CVB 41) Conducted during Ship Trials of July and August 

 1947," DTMB Report 690, March 1948, 



A vibration survey was made to determine the ship's vibration 

 characteristics with three- and four-bladed propellers. Three-bladed 

 propellers were better as far as machinery vibration was concerned and 

 four were better for hull vibration. The vibration of the outboard propul- 

 sion units was acceptable under both conditions, so the author recom- 

 mends the three-bladed propellers for the inboard shafts, and four on 

 the outboard shafts. 



Jasper, Norman H. and Andrews, John N., "Preliminary 

 Report of Strains and Motions of USS RANGER (CVA 61) 

 during a Voyage around Cape Horn," DTMB Report 1289, 

 January 1959. 



I amidships, local stresses 



ies in the shell plating forward, 



■ted for conditions tree of 



It is concluded that the flight 

 ■ n to hull-girder strength and 



iably to the stress level. 



during a mild slam 

 : a partial contributi 



62 



