- Email: [email protected]
Monitoring acoustic emissions helps detect cracks in composite parts
E Q Ul
Blade allows dry-cutting of composite specimens AEROSPACE manufacturer Martin Marietta is using a new vented blade with its VenusGusmer Bridge Saw to allow d r y - c u t t i n g of composite specimens. The Maryland office of Martin Marietta teamed up on the project with the developer of the special blade, Nasco Quality Tools of Lancaster, California. In addition to the new blade, Martin Marietta incorporated a vac u u m into its Bridge Saw to suck dust parti-
and l u b r i c a t i n g t h e blade. Martin Marietta says that accuracy and repeatability have been maintained with both techniques. In e i t h e r m o d e l , pneumatic clamps hold s a m p l e s s e c u r e l y in place during cutting. The system can prepare up to five composite s p e c i m e n s at a time. Additionally, the Bridge Saw is designed for quick changes to allow rapid preparation of specimens of varying
cles away f r o m t h e blade and specimens. T h e t e c h n i q u e has b e e n s u c c e s s f u l , reports Stephen Davies, project engineer of the firm. The Bridge Saw, released by Venus-Gusmer in 1991, performs automated production of straight-edged specimens for several ASTM and other standard material tests. Normally, it performs wet-cutting of specimens using cutting fluid to wash away particles while cooling
length and width. Venus-Gusmer has also incorporated new tooling in its Router w h i c h gives the preparation system tighter dimensional tolerances than previous models. The Router, a complementary system to the Bridge Saw, prepares tapered composite s p e c i m e n s for ASTM and other standard materials tests. Claire Niland; tel: + 1-206-8542 6 6 0 ; fax:" + 1-206854-1666.
Monitoring acoustic e m i s s i o n s helps detect cracks in c o m p o s i t e parts ACOUSTIC e m i s s i o n m o n i t o r i n g is u s e d to check that the composite parts on SAAB's new technology f i g h t e r are not sustaining any microstructural damage. Advanced c o m p o s i t e materials are used extensively in the wings and fin of the JAS39 Gripen, to provide high strength and lightweight. Thanks to the monitoring system, a problem with the highly complex loading system was prevented from damaging the costly test structure which could have held back the development programme. SAAB's full-size s t a t i c structural test programme was completed on schedule and showed the fighter to have a good structure, says SAAB pro-
ject m a n a g e r of stress analysis and testing, Thomas Lilja. The acoustic emission monitoring system used, was a 72-channel Spartan-
AT m a d e by P h y s i c a l Acoustics. The high frequency acoustic sensors, w h i c h are b o n d e d to the structure, can detect micro-cracking within
Acoustic emission sensor mounted on carbon fibre p a n e l monitors f o r micr~cracking.
Reinforced Plastics July/August 1994
lzt
a 70 cm radius on carb o n fibre, i r r e s p e c t i v e of the depth in the structure or the cracking direction. In the same w a y that earthquakes are detected and located with remote sensor by seismologists, acoustic emission sensors provide global monitoring of the structure. The technology is used extensively in the process industry to test pressurized systems, and in the UK the Royal Air Force uses the same type of system to m o n i t o r the fuselage of its VC-10 fleet during routine pressure testing. P.T. Cole, P h y s i c a l Acoustics Ltd; tel: + 44954-231612; f a x : + 44954- 2311 O2.
Blade allows dry-cutting of composite specimens AEROSPACE manufacturer Martin Marietta is using a new vented blade with its VenusGusmer Bridge Saw to allow d r y - c u t t i n g of composite specimens. The Maryland office of Martin Marietta teamed up on the project with the developer of the special blade, Nasco Quality Tools of Lancaster, California. In addition to the new blade, Martin Marietta incorporated a vac u u m into its Bridge Saw to suck dust parti-
and l u b r i c a t i n g t h e blade. Martin Marietta says that accuracy and repeatability have been maintained with both techniques. In e i t h e r m o d e l , pneumatic clamps hold s a m p l e s s e c u r e l y in place during cutting. The system can prepare up to five composite s p e c i m e n s at a time. Additionally, the Bridge Saw is designed for quick changes to allow rapid preparation of specimens of varying
cles away f r o m t h e blade and specimens. T h e t e c h n i q u e has b e e n s u c c e s s f u l , reports Stephen Davies, project engineer of the firm. The Bridge Saw, released by Venus-Gusmer in 1991, performs automated production of straight-edged specimens for several ASTM and other standard material tests. Normally, it performs wet-cutting of specimens using cutting fluid to wash away particles while cooling
length and width. Venus-Gusmer has also incorporated new tooling in its Router w h i c h gives the preparation system tighter dimensional tolerances than previous models. The Router, a complementary system to the Bridge Saw, prepares tapered composite s p e c i m e n s for ASTM and other standard materials tests. Claire Niland; tel: + 1-206-8542 6 6 0 ; fax:" + 1-206854-1666.
Monitoring acoustic e m i s s i o n s helps detect cracks in c o m p o s i t e parts ACOUSTIC e m i s s i o n m o n i t o r i n g is u s e d to check that the composite parts on SAAB's new technology f i g h t e r are not sustaining any microstructural damage. Advanced c o m p o s i t e materials are used extensively in the wings and fin of the JAS39 Gripen, to provide high strength and lightweight. Thanks to the monitoring system, a problem with the highly complex loading system was prevented from damaging the costly test structure which could have held back the development programme. SAAB's full-size s t a t i c structural test programme was completed on schedule and showed the fighter to have a good structure, says SAAB pro-
ject m a n a g e r of stress analysis and testing, Thomas Lilja. The acoustic emission monitoring system used, was a 72-channel Spartan-
AT m a d e by P h y s i c a l Acoustics. The high frequency acoustic sensors, w h i c h are b o n d e d to the structure, can detect micro-cracking within
Acoustic emission sensor mounted on carbon fibre p a n e l monitors f o r micr~cracking.
Reinforced Plastics July/August 1994
lzt
a 70 cm radius on carb o n fibre, i r r e s p e c t i v e of the depth in the structure or the cracking direction. In the same w a y that earthquakes are detected and located with remote sensor by seismologists, acoustic emission sensors provide global monitoring of the structure. The technology is used extensively in the process industry to test pressurized systems, and in the UK the Royal Air Force uses the same type of system to m o n i t o r the fuselage of its VC-10 fleet during routine pressure testing. P.T. Cole, P h y s i c a l Acoustics Ltd; tel: + 44954-231612; f a x : + 44954- 2311 O2.