Structural Testing

SPEKTRA has the following for modal analysis, fatigue tests and seismic simulation:

  • Vibration Control Systems (VCS): A family of vibration control systems for environmental simulation tests using vibration test systems.
  • Modal Exciters: A wide variety of vibration and shock exciters, which can be used to apply defined dynamic forces to larger mechanical structures for modal analysis.
  • Power Amplifier: The amplifiers have features which make them uniquely suited for studying the dynamic characteristics of structures. They may be operated in either voltage or current amplifier mode.
  • Accessories: for the different modes of operation and facilitate handling of equipment
  • Software:  LabVIEW-based software perfect match to National Instruments Hardware.


Featured Products

Vibration Control Systems (VCS)

VCS 401

The Vibration Control System VCS 401 is a system based on a powerful and scalable hardware of National Instruments®. With up to eight control channels and a scalable number of measurement channels the compact hardware is suitable for industrial applications.

  • Vibration Tests
  • Modal Excitation
  • Quality Assurance
  • Environmental Tests
  • Micro-structural Investigation
  • Sensor Testing


VCS 400

Providing well controlled vibration with one exciter in low frequency range

  • Controller for vibration test modes: sine, random, shock
  • Frequency Range: 0.1 Hz – 5 kHz (Sine)
  • Hardware base: National Instruments PXI


Modal Exciters & Components

APS 113

Ball-bearing ELECTRO-SEIS® Long-Stroke vibration exciter for modal analysis of oscillatory structures.

  • Frequency Range: DC – 200 Hz
  • Max. Force: 133 N (optional: 186 N)
  • Max. Displacement (peak-peak): 158 mm


APS 400

ELECTRO-SEIS® Long-Stroke vibration exciter with 450 N max. force that is suitable for excitation of large structures such as ceilings or bridges.

  • Frequency Range: DC – 200 Hz
  • Max. Force: 445 N
  • Velocity (Sine Peak): 1000 mm/s
  • Max. Displacement (peak-peak): 158 mm


APS 420

The strongest ELECTRO-SEIS® Long-Stroke vibration exciter to date is used for vibration tests of airplanes and other large structures. With a maximum force of 900 N and up to 150 mm stroke the shaker unlocks a new performance level.

  • Frequency Range: DC – 200 Hz
  • Max. Force: 900 N
  • Velocity (Sine Peak): 1000 mm/s
  • Max. Displacement (peak-peak): 150 mm


Power Amplifiers

APS 125

500 VA power amplifier for low-frequency vibration exciters

  • 500 watt power amplifier for modal shakers and environmental analysis
  • DC coupled amplifier
  • voltage and power mode
  • fitted to suit the vibration exciters APS 113, APS 129 and APS 500
  • safety appliances fitted to used exciter


APS 145

800 VA power amplifier for low-frequency vibration exciters

  • 800 watt power amplifier for modal shakers and environmental analysis
  • DC coupled amplifier
  • voltage and power mode
  • fitted to suit the vibration exciters APS 400, APS 420 and APS 600
  • safety appliances fitted to used exciter



APS 4001

The APS 4001 – Horizontal Reaction Mass System provides a means of extending the rated force output for the APS 400 Shaker to frequencies as low as 0.5 Hz.

  • Horizontal excitation with 400 N rated force from 0.5 Hz – 20 Hz
  • Up to 700 kg reaction mass attachable
  • Easy to disassemble and transport to a test location
  • Can be equipped with a reference force transducer (option)


APS Auxiliary Table Kits

  • Available for APS 113, APS 400 & APS 420
  • Horizontal and vertical excitation


APS Handles & Bars

Handles suitable for vibration exciter APS 113

  • Available for APS 113, APS 400, APS 420
  • for easier transport & handling


APS Reaction Mass

  • Available for APS 113, APS 400, APS 420
  • Improve the performance of the shaker


APS Modal Stinger Kit

  • Designed to deliver an axial force to the test structure and help decouple cross-axis force inputs coming from curvilinear shaker/structure motion
  • Available for APS 113, APS 400 & APS 420
  • to apply force to a structure under test


APS Steel Cable Kit

  • Needed to use the shaker in operation mode “Free Body Mode”
  • Available for APS 113, APS 113-AB, APS 400, APS 420
  • This accessory for the APS 113 shaker provides four sets of suspension lines to use the shaker in Free Body Mode.


APS Trunnion Base

Trunnion base allows easy set-up in any axis from vertical to horizontal

  • Available for APS 420
  • Trunnion Base allows the APS 420 ELECTRO-SEIS® Shaker to be set up in any axis from vertical to horizontal.


Modes of Operation

Free Body Mode

Key Features

  • Suitable if the test object is in high altitude
  • Accelerated shaker body inserts reaction force in the test structure
  • Measurement of inserted force by a force transducer or the acceleration of the shaker body

The desired force input points on many test structures lie at a considerable distance above ground level. For tests on such items, it becomes difficult and expensive to use Fixed Body Mode support structures. For such applications, the Free Body Mode can be employed. In this mode the shaker body is used as the reaction mass by suspending the shaker from an overhead support. Besides using a force transducer a very convenient measure of the load force is the axial acceleration of the shaker body. This allows simplification of the test system instrumentation, in that force can be measured with an accelerometer system which is identical to that used to measure the structural response.


Fixed Body Mode

Key Features

  • (Generated) shaker force applied directly to structure
  • Low influence on structure due to low armature mass
  • Measurement of delivered force by force transducer or shaker current

In the Fixed Body Mode, the shaker body is fixed and the armature is attached to the test structure. So shaker force is delivered directly in the test structure. In this mode, force delivered to the test structure can be measured by inserting a force transducer in the thrust linkage between the armature and test structure. Alternatively, with the armature/body suspension bands removed, shaker current can be used as a direct measure of the generated force. The generated force is approximately equal to the force delivered to a resonant test structure, because the armature mass is typically small compared to the modal mass of most large test structures.


Shaker Table Mode

Key Features

  • Horizontal and vertical long stroke tables
  • Rugged design for harsh environment
  • High payload – up to 20 kg

Auxiliary table accessory units for both horizontal and vertical use employ the high load capability of the APS 113 armature guidance and suspension systems to provide long stroke tables for excitation of test loads. Each auxiliary table has a pattern of threads with helical inserts to mount the test load directly or a fixture on the table. The mechanical input impedance at the base of a test load that is resonant in the operating frequency range can vary significantly. Thus, the acceleration response of the table and test item base will exhibit the familiar „peaks“ and „notches“ as frequency is varied. So it is recommended to observe the response of the structure using accelerometers.


Reaction Mass Mode

Key Features

  • Inertial vibration exciter
  • Vertical or horizontal operation
  • Easy to install reaction mass

Many large test structures having horizontal surfaces such as floors require vertical or horizontal force applied to these surfaces to generate resonant modes of vibration. The APS shakers may be used in a vertical or horizontal Free Armature Mode by resting the shaker body on the horizontal surface. The moving armature provides a reaction mass that allows for delivery of the shaker force via the shaker body to the surface (inertial shaker). Below a certain cross-frequency the shaker stroke limits the acceleration of the armature and thus the maximum force. Additional masses, e.g. APS 0112 or 4001, lower this frequency. The force applied to the structure can be measured by a force transducer or by measuring the acceleration of the moving masses.



Flexible Software Components

SPEKTRA has software that is a perfect match to the National Instruments hardware. It is a LabVIEW-based software solution. So it can easily be integrated into your environment. The LabVIEW software package allows for driving several exciters

to achieve different physical measurements in parallel and updating the test system for further purposes as required. In addition you can use it for laboratory applications and scale it up to an automated test system.

  • Scalable technology, from a very simple control unit up to a very high performance and multi-channel controller
  • Operation modes: sine, random, shock, chart, FDR, …
  • Coordinated synchronized multi-channel excitation, also synchronized 3-dimensional excitation possible
  • Customer-specific individual extensions on request

 Your Benefits

  • Single and multichannel excitation
  • Synchronized or individual channels
  • Locked phase with adjustable and controlled phase shift for multiple I/O channels
  • Earthquake simulation
  • Field data replication (FDR)
  • Multi-channel data acquisition
  • Intuitive handling
  • Database
  • Remote control
  • Synchronizing and trigger signals
  • Reports & monitoring
  • Frequency range 0.01 Hz – 95 kHz
  • Integration of laser vibrometer