Vibrophores for Determining Durability with Regard to Fatigue Life and Fatigue Limit (LLF)

Due to their design, Vibrophores have been used in the past solely as dynamic materials testing machines to determine durability with regard to fatigue life and fatigue limit (LLF), for example for fatigue testing to DIN 50100 (S-N curve) under tensile, compression, pulsating and alternating loads.

The new generation of Zwick Vibrophores can be used as both dynamic and full-fledged static materials testing machines that accommodate test loads up to 1000 kN. Typical applications are material fatigue tests and durability tests on standardized specimens and components (for example, piston rods, crankshafts, and screws) and production and quality control of components exposed to dynamic loads during their service lives, such as concrete and reinforcing steel, as well as quasi-static tensile and compression tests and fracture mechanics tests on CT and SEB specimens.

250 kN Vibrophore for determining the fatigue life and fatigue limit (LLF)

Significant Advantages and Features

Advantages & features

  • Optimal conditions in relation to the exact alignment of test axes thanks to the stiff 4-column frame - Prevention of mechanical influences on the specimen - Precise measurement results
  • Reliable testing of both short and long specimens made possible by the large crosshead travel.
  • Ergonomic operation thanks to low mounting table
  • Repeatable and precise specimen change for defined grip-to-grip separation thanks to integrated crosshead travel measuring system
  • Minimal maintenance costs because there are no wear parts
  • Easy to install—no ancillary infrastructure (for example, hydraulics, coolant, compressed air) required

"Two in one"

"Two in one"—The Vibrophore Is a Full-Fledged Dynamic and Static Testing Machine in One 

Dynamic testing with the Vibrophore

The operating principle of the Zwick Vibrophore is based on the concept of a mechanical resonator with electro-magnetic drive. The mean force is applied by moving the upper crosshead with the lead screw drive. The dynamic load is generated by an oscillation system that works when the system operates at full resonance. In this way test frequencies of up to 285Hz are possible, provided specimens are sufficiently stiff. Both drives (those of the dynamic and static parts), are controlled independently of one another, making possible any type of stress ratios (r-ratios). Tests can be force, displacement, or strain-controlled.

Static testing with the Vibrophore

The Vibrophore is transformed into a fully-fledged static materials testing machine thanks to mechanical clamping of the oscillating crosshead and testXpert II software.

Generous connecting surfaces and ruggedly dimensioned components ensure high machine stiffness. Together with precise crosshead guidance, undesired mechanical influences on the specimen are minimized. By using additional fixtures, both static and dynamic testing can be performed under various environmental conditions (temperature, aggressive media), together with torsion and flexure tests. The absence of a central lead screw enables test area versatility to be maximized on the new Vibrophore, meaning it is possible to test very short specimens as well as large components.

Advantages of the "Two-in-One" Principle

  • Short test times and a high specimen throughput level for dynamic tests due to high frequencies
  • Minimum energy is required thanks to the resonance principle (approx. 2% of the energy required by a servohyraulic testing machine)

Technical Overview

Vibrophore 100

Description

Value

Fmax

100

kN

Mean load max.

±100

kN

Force amplitude max.

±50

kN

Specimen elastic strain (oscillation displacement) max.

6 (±3)

mm

Test frequency range[1]

30 ... 285

Hz

No. of frequency steps[2]

8

No. of guide columns

4

No. of lead-screw drives

2

Frame stiffness at 1000mm crosshead separation [3]

approx. 380

kN/mm

Drive

Static tests and for mean force control

AC drive

min. crosshead speed

0.0001

mm/min

max. crosshead speed

600

mm/min

max. crosshead return speed

1000

mm/min

repeat positioning accuracy on crosshead

±2

µm

motor holding brake

yes

Dynamic tests

wear-free electro-magnetic drive

Load-frame dimensions

H4 - height

2570

mm

H3 - clamping-table height

807

mm

B2 - width

1095

mm

T3 - depth

775

mm

Approx. weight[4]

3200

kg

Test area dimensions

Test-area height without load cell

1200

mm

Test area depth

550

mm

Free access width between columns

626

mm

Max. travel, machine frame

977.5

mm

Item No.

Vibrophore 100 including testControl II

084142

Optional: two in one for static tests

1009579

Optional: oscillation displacement measurement

1001259

Optional: lead screw protection for the testing area placed above the moving crosshead

1016430

Optional: lead screw protection for the testing area placed below the moving crosshead

1016431

  1. The testing frequency is determined by the stiffness and mass of the test arrangement.
  1. via activation / deactivation of weights
  1. Load frame stiffness: this value is obtained via direct deformation measurement between the crossheads (moving and base crossheads) and does not take into account deformation of the drive and load cell.
  1. Weight without specimen grips or fixtures

Vibrophore 250

Description

Value

Fmax

250

kN

Mean load max.

±250

kN

Force amplitude max.

±125

kN

Specimen elastic strain (oscillation displacement) max.

6 (±3)

mm

Test frequency range[1]

30 ... 285

Hz

No. of frequency steps[2]

8

No. of guide columns

4

No. of lead-screw drives

2

Frame stiffness at 1000mm crosshead separation [3]

approx. 380

kN/mm

Drive

Static tests and for mean force control

AC drive

min. crosshead speed

0.0001

mm/min

max. crosshead speed

600

mm/min

max. crosshead return speed

1000

mm/min

repeat positioning accuracy on crosshead

±2

µm

motor holding brake

yes

Dynamic tests

wear-free electro-magnetic drive

Load-frame dimensions

H4 - height

2570

mm

H3 - clamping-table height

807

mm

B2 - width

1095

mm

T3 - depth

775

mm

Approx. weight[4]

3200

kg

Test area dimensions

Test-area height without load cell

1200

mm

Test area depth

550

mm

Free access width between columns

626

mm

Max. travel, machine frame

925

mm

Item No.

Vibrophore 250 including testControl II

1001253

Optional: two in one for static tests

1009579

Optional: oscillation displacement measurement

1001259

Optional: lead screw protection for the testing area placed above the moving crosshead

1016430

Optional: lead screw protection for the testing area placed below the moving crosshead

1016431

  1. The testing frequency is determined by the stiffness and mass of the test arrangement.
  1. via activation / deactivation of weights
  1. Load frame stiffness: this value is obtained via direct deformation measurement between the crossheads (moving and base crossheads) and does not take into account deformation of the drive and load cell.
  1. Weight without specimen grips or fixtures

Vibrophore 1000

Description

Value

Fmax

1000

kN

Mean load max.

± 1000

kN

Force amplitude max.

± 500

kN

Testing frequency range

30 – 150

Hz

Number of frequency stages[1]

8

Number of lead columns

4

Number of drive columns

2

Stiffness of load frame

crosshead deflection and elongation of lead screw drive approx.

1600

kN/mm

  1. by activation / deactivation of weights

Design

68831

testControl II measurement and control electronics

testControl II measurement and control electronics

Control frequency

10 kHz

Measured-value acquisition

10 kHz, 24 bits, arithmetical

Slots

5 x module bus (2 occupied as default)

PC interface

GigaBit Ethernet

Integrated safety concept

2-channel specification for maximum safety

interface for interlocked safety doors

interface for Emergency STOP loop

Display-equipped remote control unit

set-up or testing mode

Emergency STOP button

key-switch for switching between setup and testing modes

Dimensions, testControl II measurement and control electronics

H1-height without table plate

1000

mm

B1-width

600

mm

T1-depth

600

mm

Approx. weight

135

kg

Length of cable Vibrophore - testControl II

5

m

Accessories

Universal measurement amplifier (029443)

Choice of AC/DC supply

Half and full-bridge strain-gages

4 and 6-conductor technology

I/O card (029448)

1 analog ± 10V input (controllable)

2 analog ± 10V outputs

4 digital inputs, 24V

3 digital outputs, 24V

1 relay output, potential-free

Zwick supports product development at Abeking & Rasmussen

Abeking & Rasmussen is a shipyard at Lemwerder on the Ufer (Germany) with a long tradition of ship and yacht-building. The yard's 400 or so employees build premium-quality specialized vessels such as minesweepers, official vessels and speedboats, together with motor and sailing yachts for discerning customers around the world. The emphasis is on longevity, elegance and technical perfection. Zwick has assisted Abeking & Rasmussen in specifying a suitable test method for assessing new fasteners.
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