CENTROTECNICA S.r.l. PRISMS AND CUBES. Shaker s ancillary equipment

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1 CENTROTECNICA S.r.l. PRISMS AND CUBES Shaker s ancillary equipment

WHY A PRISM? WHY A CUBE? Almost all vibration tests should be performed along 3 orthogonal axes. The axis can be moved by rotating the item on a slip-table, on a prism or on a cube.

PRISM The prism can be considered as a substitute of the slip table. Two opposite faces with the same inserts pattern can be used to test the items.

expander. Main features: Light structure 2 opposite faces to be used together High resonance frequencies if the loads on the two faces are well balanced.

2 WHY A PRISM? WHY A CUBE? Almost all vibration tests should be performed along 3 orthogonal axes. The axis can be moved by rotating the item on a slip-table, on a prism or on a cube. Our experience in vibration tests suggests that other structures like L an T fixtures in most of cases alter vibration test by unwanted resonances. PRISM The prism can be considered as a substitute of the slip table. Two opposite faces with the same inserts pattern can be used to test the items. The prism can be used to perform the in-plane (horizontal) axis while the out-of-plane (vertical) axis has to be performed fixing the items directly on the shaker armature or on an expander. Main features: Light structure 2 opposite faces to be used together High resonance frequencies if the loads on the two faces are well balanced. CUBE Prism 5 faces can be used to fix many items on a cube. The possibility to perform a test along 3 orthogonal axis without removing it is the main advantage of a cube. A three axis test on three different items can be performed by running the profile three times instead of nine if an L fixture is used. Main features: Cube Internally caved to save weight Save time using 5 faces High frequency range up to 335mm Manufacturing Cubes and prisms are machined from solid or casted: CASTED Several standard patterns are used to cast in aluminium or magnesium alloy the larger cubes and prisms. MACHINED Smaller cubes and prisms can be machined from solid aluminium or magnesium alloy.

OPTIONS TOP HAT WASHERS Stainless steel Top-Hat-Washers are forced into the fixing holes. This feature prevents deformations of the material due to the fixing screws.

This is a standard feature on casted items.

3 OPTIONS TOP HAT WASHERS Stainless steel Top-Hat-Washers are forced into the fixing holes. This feature prevents deformations of the material due to the fixing screws. When installed, the use of washers is not necessary. To help the operator to choose proper fixing screws length, a drawing is included it the technical report. This is a standard feature on casted items. Prism or Cube Top Hat Washer MODES All prisms have three main vibration mode shapes: TRANSVERSAL MODE SHAPE The transversal mode shape is excited only in case of unbalanced payloads (for instance if an item is mounted on a face and the opposite face is free). Balancing the payload on prisms and cubes increase the usable frequency range and preserves shaker internal guidance system. TORSIONAL MODE SHAPE The torsional mode is negligibly excited by the shaker AXIAL MODE SHAPE: FIRST RESONANCE The axial mode shape is always excited by the shaker and causes the prism main resonance. This mode shape usually presents a high frequency thanks to the high axial stiffness of the material. Up to a dimension of 440 mm the main resonance is over 2000 Hz. CUBES AND PRISM CAN BE FULLY CUSTOMIZED UPON REQUEST!

4 CUBES AND PRISM SAMPLES 525x445x245 mm magnesium prism with dow17 treatment - Application in aerospoce industry 485x486x343 mm magnesium prims - Application in telecoms industry 330x330 mm prism available in aluminium and magnesium

176 M8 inserts on 50 grid pattern Rendering of a 335 mm

5 CUBES AND PRISM SAMPLES Prismatic fixture - Application in automotive industry 335 mm cube for 440 armature with 176 M8 inserts on 50 grid pattern Rendering of a 335 mm cube for 440 armature with 120 M8 inserts on 100 grid pattern

6 STANDARD INSERTATION ALUMINIUM CUBES ARMATURE LENGHT (mm) WIDTH (mm) HEIGHT (mm) MASS (kg) N INSERT M8 OPTIONS DELIV. WKS. Ø , Ø , Ø , Ø Ø 432, I Ø 432, I , THW THW 8 STANDARD INSERTATION MAGNESIUM CUBES ARMATURE LENGHT (mm) WIDTH (mm) HEIGHT (mm) MASS (kg) N INSERT M8 OPTIONS DELIV. WKS. Ø , Ø Ø , Ø Ø 432, I Ø 432, I , THW THW 8

7 STANDARD INSERTATION ALUMINIUM PRISMS ARMATURE LENGHT (mm) WIDTH (mm) HEIGHT (mm) MASS (kg) N INSERT M8 OPTIONS DELIV. WKS THW THW THW THW THW 8 STANDARD INSERTATION MAGNESIUM PRISMS ARMATURE LENGHT (mm) WIDTH (mm) HEIGHT (mm) MASS (kg) N INSERT M8 OPTIONS DELIV. WKS THW THW THW THW THW 8

8 ARMATURES SAMPLES ARMATURES A B C D E F OTHER ARMATURES SIZES AVAILABLE ON REQUEST G CT/04.13/Eng./Rev. 1 CENTROTECNICA S.r.l. Headquarter and Test House: Via N. Sauro, Peschiera Borromeo (MI) - ITALY Production Unit and Test House: Via F. Confalonieri, Masate (MI) - ITALY Tel: Fax: info@ctecnica.it - Website: ISO Cert. n. 2156/3

(Based on a paper presented at the 8th International Modal Analysis Conference, Kissimmee, EL 1990.)

(Based on a paper presented at the 8th International Modal Analysis Conference, Kissimmee, EL 1990.) Design Optimization of a Vibration Exciter Head Expander Robert S. Ballinger, Anatrol Corporation, Cincinnati, Ohio Edward L. Peterson, MB Dynamics, Inc., Cleveland, Ohio David L Brown, University of Cincinnati,