Ultrasonic search-wheel assembly

Determin~ttion of aco ustic t r ~ m d u c e r con-

version l o s s by impedance measurements Wauk, M.T., Winslow, D. K. I EEE T r a n s a c t i o n s on so nics and U l t r a sonics, Vol SU-16, No 3 (July 1969), pp 86

(1921) Lead zircouate--lead t i t a n a t e p i e z o - e l e c t r i c

c e r a m i c s with iro n oxide additions Weston, T. B., Webster, A. H. and McNamara, W.M. Jour nal of the A m e r i c a n C e r a m i c Society Vol 52, No 5 (21 May 1969) pp 253-257 (1922) Piezoelectric-transistorized sensitive elements and microphones Zarkhin, V. I., Kolomystev, B. R., Syrkin, L. N. Soviet P h y s i c s - A c o u s t i c s Vol 15, No 2 (OctDec 1969), pp 192 (1923)

NON-DESTRUCTIVE TESTING

Acoustic b eam scanning by optical control of piezoelectric coupling Auld, B. A., Webb, D. C. and Winslow, D. K. Proc IEEE (April 1969) p 713 P i e z o e l e c t r i c coupling to an acoustic s y s t e m can be controlled with an optical beam when using photoconductors such a s CdS, CdSe, ZnO and ZnS. The effective impedance of the CdS film t r a n s d u c e r used was a p a r a l l e l RC circuit, in s e r i e s with a capacitance r e p r e s e n t i n g the fringing e l e c t r i c field in a contacting sapphire c r y s t a l . Illumination of the CdS film changes R, and t h e r e f o r e the micr owave e l e c t r i c field strength. Using an acoustic echo train at 1.5GHz with InS pulses, and r . f . p o w e r input about 100mW, two-way conversion efficiency was found to change by up to l l d B when propagating f i r s t without, then with, a white light source. In a possible application of a surface wave transducer, illumination of a photoconductive p i e z o e l e c t r i c l a y e r by a p e r i o d i c light pattern would produce a pattern of a l t e r n a t i n g low and high coupling reg ions which could be phase matched to the d e s i r e d surface. (1924)

The detection of incipient f a i l u r e in bearings Balderston, H. L. M a t e r i a l s Evaluation, Vol 27, No 6 (June 1969) 121-128 Detection of incipient failure i s g e n e r a l l y r elated to the detection of the b a s i c c a u s e s of failure. In this paper, defects which lead to f ailur e a r e c r e a t e d a n d / o r s i m u l a t e d and a r e detected utilizing resonant frequency techniques falling in the u l t r a s o n i c frequency range. Rotational f r e q u e n c i e s of the b e a r i n g a r e calculated and identified; resonant f r e quencies a r e calculated and identified. Corr elation is shown between r . m . s , amplitude at these frequencies and the s e v e r i t y of the defects incorporated. Frequency t r a n s l a t i o n techniques a r e employed to b r i n g the u l t r a s o n i c resonant frequencies used to detect defects within the range of hearing. A tape r e c o r d i n g has been made of t r a n s l a t e d frequency data which enables the l i s t e n e r to differentiate between the v a r i o u s defects which cause f a i l u r e s within the b e a r i n g s . (1925) Acoustical holography as a tool for non-

destructive testing Brenden, B. B. M a t e r i a l s Evaluation, Vol 27, No 6 (June 1969) pp 140-144 Acoustical imaging by m e a n s of holography has been shown to be an effective m e a n s for producing an optical imag e of an a c o u s t i c a l p r e s s u r e field. Several applications a r e d e s c r i b e d and r e s u l t s of i n i t i a l i n v e s t i g a t i o n s presented. These applications include i m a g ing flaws in butt welds, voids in 4In-thick aluminum of steel and t u m o r s growing in live r a t s . (1926) 70

ULTRASONICS January

1970

Ultrasonic/radiographic examination of heavy-wall pressure vessel weldmenis Center, D. E. and Roehrs, R. J. M a t e r i a l s Evaluation, Vol 27, No 5 (May 1969) pp 107-117 Since the e a r l y 1900's when the National Board of B o i l e r and P r e s s u r e V e s s e l Inspect o r s was organized, i n c r e a s e d operating t e m p e r a t u r e s and p r e s s u r e s have caused g r e a t e r e m p h a s i s on the safe construction of chemical and p e t r o l e u m p r o c e s s i n g equipment. Though many ndt methods a r e p r e s ently used to prove weld integrity, this paper p r e s e n t s an a n a l y s i s of u l t r a s o n i c and r a d i o graphic examinations of heavy wall p r e s s u r e v e s s e l weldments. S i m i l a r i t i e s and differences in the two methods a re d i s c u s s e d . There has been some re l uc t a nc e to use u l t r a sonics to examine welds but t hi s inspection method has continually proved to be valuable for detecting planar type defects such as cracks, lack of fusion and lack of penetration. Since u l t r a s o n i c inspection of welds i s not mentioned in Section VE[I of the ASME Code, controlled studies have been made to d e t e r mine the f e a s i b i l i t y of using t hi s method as a supplement to p r e s e n t ASME acceptable radiographic procedures, and some r e s u l t s a r e d i s c u s s e d along with the findings of actual production weld testing. (1927) An u l t r a s o n i c c r a c k growth monitor C l a r k Jr., W. G. and Ceschini, L. J. M a t e r i a l s Evaluation, Vol 27, No 8 (August 1969), pp 180-184 C o m m e r c i a l l y available u l t r a s o n i c flaw detection equipment has been applied by the authors to c r a c k growth monitoring of the wedge-opening-loading (WOL) f r a c t u r e toughn e s s specimen. The e s s e n c e of the technique is to r e l a t e the position of the t r a n s d u c e r on the specimen surface to the extent of c r a c k growth by moving the t r a n s d u c e r to maintain a constant flow signal from the tip of the propagating cr a c k. The t r a n s d u c e r i s moved in 0.010in i n c r e m e n t s and supplies 10Hz ultrasound. R e s u l t s a r e given c ompa ri ng visual c r a c k growth moni t ori ng with the s y s t e m and c r a c k growth V e l a ps e d c y c l e s of load graphs a r e produced. (1928) Ultrasonic inspection of t h i n - w a l l piping by mauuat methods Collier, J. W. M a t e r i a l s Evaluation, Vol 27, No 4 (April 1969) pp 73-76 Utilizing u l t r a s o n i c inspection on thin-wall piping p r e s e n t s many p r o b l e m s when the t r a n s d u c e r is manually operated. 'Drop through' of weld m a t e r i a l and e x c e s s i v e weld crown p r e s e n t the l a r g e s t p r o b l e m s be c a us e of different r e f l e c t i n g s urfa c e s . The n a r r o w contact surface between the s e a r c h unit and the pipe poses another m a j o r problem a s does the beam t r a v e l the technician has to cope with, due to the t hi c kne s s of the pipe (. 158 or . 218 of an inch). These p r o b l e m s were solved through e xpe ri me nt a t i on and applying a few u l t r a s o n i c p r i n c i p l e s that a re often over looked. The r e s u l t s w e re checked against extensive radiography a n a l y s i s .

(1929) Ultrasonic search-wheel assembly Cowan, G. de G. US Patent 3, 442, 119 (6 May 1969) (Filed 11 October 1965) The method allows simultaneous u l t r a s o n i c and inductive t e s t i n g of r a i l w a y l i n e s for internal defects. An u l t r a s o n i c s e a r c h - w h e e l i s provided which has a l y r e and re i nforc e d side walls. Ribs on the t r e a d r e t a i n acoustic coupling to the r a i l at a l l t i m e s . The re i s also a facility for e n s u r i n g that wheel and inductive pick-up a r e c o r r e c t l y oriented with the r a i l at all t i m e s . (1950) Ultrasonic flaw detector for components with curved s u r f a c e s Dr Lehfeldt & Co G e r m a n Patent 1294070 (Applied for 30 A p r i l 1969)

Has a curved head, acting a s t r a n s m i t t e r and r e c e i v e r , with an optical a x i s that m a k e s an angle with the norma l to the component. This angle i s chosen such that the sound waves inpinge the component e v e r y w h e r e at the s a me angle and a r e r e f r a c t e d into the component and around the curved surface. Any lock r e f l e c t i o n s a r e detected showing any flaws. (1931) Multiscan u l t r a s o n i c testing apparatus Flaherty, J. J. and Rosaner, P. J. US Patent 3, 438, 530 (22 A pri l 1969) (Filed 10 January 1966) Several t r a n s d u c e r s a r e o s c i l l a t e d to produce t r a n s v e r s e scanning of b e a m s through portions of a sample. B - s c a n indications being produced on an os c i l l os c ope s c r e e n according to the a r e a scanned. The portions scanned a re made to overlap so that indications re i nforc e one another and thus m in imi z i ng random effects. (1932) Ultrasonic t e s t i n g of c o l d - r o l l e d s t r i p with Lamb waves using the echo method Holler, P., and Smit, H. Materialpfifung, Vol 11, No 10 (October 1969) pp 329-335 The t r a n s v e r s e echo method has been examined for different types of waves, probes and probe a r r a n g e m e n t s . The excitation of Lamb waves and the construction of probe s a r e discussed. It i s shown that the detection s en s i t i vi t y i s about 0. l m m line width when using probe s with s e p a r a t e d t r a n s m i t t e r and r e c e i ve r. The n a r r o w flaw l i n e s re fl e c t only l e s s than 1% of the incident energy. This slight reflection m a k e s it pos s i bl e to locate single flaw l i ne s in a va ryi ng distance. Different line widths can be distinguished too under c e r t a i n suppositions. By means of some e x a m p l e s this method i s compared with the t r a n s m i s s i o n method. (1933) Method of coupling liquid heads with u l t r a sound Huttenwerk Oberhausan AG French Patent 1,565, 567 (2 May 1969) (Applied for 14 March 1968) (In West Germany 22 March 1967) A method of u l t r a s o n i c a l l y coupling liquid heads to the surface of control pi e c e s by placing a coupling liquid between the head and the surface. A liquid capsule goes with the flow and offers a definite obstacle to the liquid which then gives way in the region of the head. (1934) Ultrasonic gauging made versatile Metalworking Production (26 March 1969) An account of how wall t h i c k n e s s was m e a s u r ed for a work piece that had c o n s i d e r a b l e v a r i a t i o n s in wail thickness thereby e l i m i n a t ing norma l re s ona nc e probe techniques. D i re c t r e a d i n g s w e re obtained from an u l t r a sonic t h i c k n e s s gauge. The e r r o r r e m a i n e d within design l i m i t s . (1935)

New p o s s i b i l i t i e s of routine inspection of grey iron castings by ultrasonic attenuation tests shown by the e~ample of b e a r i n g caps for diesel engines Meyer, H-J. Materialpriifung, Vol 11, No 10 (October 1969) pp335-340 Ultrasonic p u l s e s of a definite frequency and wavelength undergo a v a r y i n g degree of s c a t t e r depending on the s i z e and quantity of graphite fl a ke s in grey c a s t iron. The amount of sound energy left a ft e r t h i s sound beam ha s p a s s e d a given c r o s s - s e c t i o n t h e r e f o r e p r o v i d e s a m e a s u r e of the s t r u c ture, di s t ri but i on and content of graphite and, consequently of the phys i c a l strength in t hi s c r o s s section. (1936} Foundry t e s t i n g device P a t t e r s o n W. G e rma n Patent 1,296, 826 (Applied ~or 4 June 1969) Expansion i s m e a s u r e d on a t e s t s pe c im en which ha s been c o m p r e s s e d to a disc, heated