Ac Lo Thuras, 0» Ho Schnuckj, F„ Pc Bundy, Mo Ho Hebb s and Lc No 

 Miller made Important contributions to magnetostriction trans- 

 ducer development o 



Almost every laboratory engaged In applications of sub- 

 surface sound s devoted some attention to the analysis of the 

 directional patterns of sound radiators^ the primary objective 

 being to eliminate the spurious sound radiation characterized 

 by minor lobes G As a result of the work of H Brooks and 

 others it was possible to establish specifications for pro- 

 ducing directivity patterns of any degree of sharpness and 

 freedom from minor lobes „ provided the surface of the radiator 

 could be excited according to any prescribed pattern of phase 

 and amplitude » These mathematical conditions had a physical 

 counterpart in the construction of transducers as arrays of 

 small stacks of thin laminations whose individual excitations 

 could be controlled in accordance with the theoretical require- 

 ments o One typical transducer constructed on this basis was 

 designated SPEP and exhibited an excellent directivity pattern 

 as well as the high efficiency characteristic of the laminated 

 stack construction. 



Theoretical consideration was also given to the formation 

 of sharply directive sound beams by multi-element cylindrical 

 arrays of transducer elements „ Proper specifications for the 

 distribution of amplitude and phase among the elements of the 

 array were found and conditions were established for the rota- 

 tion of the directive patterns so formed about the axis of the 

 array without distortion^ by suitably modulating the amplitude 

 and phase of the excitation of the individual elements 



As is true with most research programs that of Division 6 

 on magnetostriction transducers uncovered many new problems 

 for each one solved. Most of the transducer designs which 

 were studied related to vibrating systems of a single degree 

 of freedom. Further study could profitably be devoted to wide 

 range transducers possessing additional degrees of freedom 

 In the field of magnetostrictlve materials there Is still room 

 for improvement of the factors which increase the tightness 

 of the coupling between the electrical and mechanical circuits 

 and for further reduction of the eddy current losses . 



Research on Piego-jElectrir Transducers, 



Plezo-electrle materials are crystals which when com- 

 pressed in particular directions accumulate electrical charges 



39 



