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.
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.
Prism
CUBE
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
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.
Internally caved to save weight
Save time using 5 faces
High frequency range up to 335mm
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.
Prism or
Cube
This is a standard feature on casted items.
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!
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
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
STANDARD INSERTATION ALUMINIUM CUBES
ARMATURE
LENGHT (mm)
WIDTH (mm)
HEIGHT (mm)
MASS (kg)
N° INSERT M8
OPTIONS
DELIV. WKS.
Ø 110
78
78
78
0,8
20
-
6
Ø 110
110
110
130
2,6
41
-
6
Ø 156
110
110
110
2,2
45
-
6
Ø 156
156
156
176
7
45
-
6
Ø 180
Ø 181
Ø 335
127
127
127
3
45
-
6
Ø 180
Ø 181
Ø 335
198
198
223
12
80
-
6
Ø 240
Ø 432, I
Ø 440
180
180
180
7
45
-
6
Ø 240
Ø 432, I
Ø 440
240
240
275
22,6
80
-
6
Ø 335
Ø 440
240
240
240
15
80
-
6
Ø 180
Ø 181
Ø 335
180
180
215
11
45
-
6
Ø 432, M, I
Ø 440
335
335
370
63
176
THW
8
Ø 432, M, I
Ø 440
350
350
380
53
120
THW
8
STANDARD INSERTATION MAGNESIUM CUBES
ARMATURE
LENGHT (mm)
WIDTH (mm)
HEIGHT (mm)
MASS (kg)
N° INSERT M8
OPTIONS
DELIV. WKS.
Ø 110
78
78
78
0,6
20
-
10
Ø 110
110
110
130
2
41
-
10
Ø 156
110
110
110
1,5
45
-
10
Ø 156
156
156
176
5
45
-
10
Ø 180
Ø 181
Ø 335
127
127
127
2
45
-
10
Ø 180
Ø 181
Ø 335
198
198
223
8
80
-
10
Ø 240
Ø 432, I
Ø 440
180
180
180
5
45
-
10
Ø 240
Ø 432, I
Ø 440
240
240
275
15
80
-
10
Ø 335
Ø 440
240
240
240
10
80
-
10
Ø 180
Ø 181
Ø 335
180
180
215
7,5
45
-
10
Ø 432, M, I
Ø 440
335
335
370
43
176
THW
8
Ø 432, M, I
Ø 440
350
350
380
35
120
THW
8
STANDARD INSERTATION ALUMINIUM PRISMS
ARMATURE
LENGHT (mm)
WIDTH (mm)
HEIGHT (mm)
MASS (kg)
N° INSERT M8
OPTIONS
DELIV. WKS.
Ø 180
Ø 181
Ø 335
180
180
100
7
34
-
6
Ø 180
Ø 181
Ø 335
280
280
190
31
58
Ø 240
Ø 432, M, I
Ø 440
280
280
190
31
58
Ø 335
Ø 440
330
330
190
42
50
THW
8
Ø 432, M, I
440
440
245
68
170
THW
8
Ø 440
440
440
245
68
170
THW
8
Ø 432, M, I
445
525
245
95
160
THW
8
Ø 440
445
525
245
95
160
THW
8
-
-
6
6
STANDARD INSERTATION MAGNESIUM PRISMS
ARMATURE
LENGHT (mm)
WIDTH (mm)
HEIGHT (mm)
MASS (kg)
N° INSERT M8
Ø 180
Ø 181
Ø 335
180
180
100
5
34
Ø 180
Ø 181
Ø 335
280
280
190
21
58
Ø 240
Ø 432, M, I
Ø 440
280
280
190
21
58
Ø 335
Ø 440
330
330
190
28
50
Ø 432, M, I
440
440
245
46
Ø 440
440
440
245
Ø 432, M, I
445
525
Ø 440
445
525
OPTIONS
DELIV. WKS.
-
10
-
-
10
10
THW
8
170
THW
8
46
170
THW
8
245
64
160
THW
8
245
64
160
THW
8
ARMATURES SAMPLES
ARMATURES
A
B
C
D
E
F
CT/04.13/Eng./Rev. 1
OTHER ARMATURES‘ SIZES
AVAILABLE ON REQUEST
G
CENTROTECNICA S.r.l.
Headquarter and Test House: Via N. Sauro, 1 - 20068 Peschiera Borromeo (MI) - ITALY
Production Unit and Test House: Via F. Confalonieri, 23 - 20060 Masate (MI) - ITALY
Tel: +39 02 55305888 - Fax: +39 02 45503582
Email: [email protected] - Website: www.centrotecnica.net
ISO 9001 - Cert. n. 2156/3