Destructive Load Test of FlexiCrane · 2018-04-13 · The FlexiCrane used in the test, shown below,...
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SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected] 1 Destructive Load Test of FlexiCrane Document prepared by Frederik Nielsen Document reviewed by Kåre Tanggaard Load test performed 20-05-2016 by Frederik Nielsen Kåre Tanggaard Per Bak Christensen Jesper Nielsen Andrei Maierean Contents Scope ................................................................................................................................................................. 2 Setup.................................................................................................................................................................. 2 Safety ................................................................................................................................................................. 3 Results ............................................................................................................................................................... 3 Evaluation .......................................................................................................................................................... 7 Date: 31-05-2016 Rev: 00
Transcript of Destructive Load Test of FlexiCrane · 2018-04-13 · The FlexiCrane used in the test, shown below,...
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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Destructive Load Test of FlexiCrane
Document prepared by Frederik Nielsen
Document reviewed by Kåre Tanggaard
Load test performed 20-05-2016 by
Frederik Nielsen Kåre Tanggaard Per Bak Christensen Jesper Nielsen Andrei Maierean
Contents Scope ................................................................................................................................................................. 2
Setup .................................................................................................................................................................. 2
Safety ................................................................................................................................................................. 3
Results ............................................................................................................................................................... 3
Evaluation .......................................................................................................................................................... 7
Date: 31-05-2016 Rev: 00
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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Scope All structural properties of the various FlexiCrane configurations are based on the same design basis and
calculations. A destructive load test of a FlexiCrane could verify the failure modes and load limits of all
FlexiCrane configurations.
The failure mode is interesting with regard to safety of the FlexiCrane, and the load limit could verify that
all calculations, including FEM, are conservative.
Setup The FlexiCrane used in the test, shown below, is based on the first design of the FlexiCrane.
Figure 1: The setup of the load test
A few differences exist between the old design and the new design. In the old design:
- The modules are tapered.
- The distance between each module is slightly larger (from 0.5 mm to 2 mm).
- The new modules have two Ø20.15 holes through the body of the modules, which are used for the
stork.
- The lifting eye is welded onto the last module of the FlexiCrane.
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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The FlexiCrane consists of 18 modules and has a reach of 3.7 meters. It was originally designed for lifts up
to 240 kg at the last module, being limited by the electric hoist (Kito electrical hoist, WLL 240 kg).
The FlexiCrane properties, by using the same strength calculations, design basis and safety factors as the
new FlexiCrane design, is the following:
Table 1: Structural properties of the FlexiCrane used for loadtest based on new calculations with a DAF (Dynamic Amplification Factor) of 1.3.
Notice the WLL in the last module is 330 kg.
The load test was performed in the courtyard of Sahara 4, a SubC Partner location. The FlexiCrane is
installed on the stainless steel taps welded onto flanges and a column. A 12T loadcell is attached to the last
module, and further attached to a 2T chain block. This connects to lifting slings attached to a heavy steel
beam.
Safety The area around the load test was cleared and all personnel performing the loadtest was required to wear
full PPE. This includes High visibility vest, safety glasses, work boots, gloves and safety helmet. The hoist
was manually operated, but had a 20-meter chain. This chain is guided under the beam, allowing
approximately 6-meter distance between the operator and the load.
Results The crane deforms heavily, and a few of the largest modules rotates very slightly at around 1000 kg.
Destruction occurs at 1450 kg, see the following figures.
Module No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Lifting Radius [m] 0.205 0.410 0.615 0.820 1.025 1.230 1.435 1.640 1.845 2.050 2.255 2.460 2.665 2.870 3.075 3.280 3.485 3.690
WLL [kg] 500 500 500 500 500 500 500 500 500 500 500 500 495 450 415 380 355 330
Profile Height [m] 0.772 0.741 0.710 0.679 0.648 0.617 0.586 0.555 0.524 0.493 0.462 0.431 0.400 0.369 0.338 0.307 0.276 0.245
Profile Mass [kg] 13.6 13.0 12.5 12.0 11.5 11.0 10.4 9.9 9.4 8.9 8.3 7.8 7.3 6.8 6.3 5.7 5.2 4.7
Deflection from WLL [m] < 0.02 < 0.02 < 0.02 < 0.02 < 0.02 < 0,02 < 0,02 0.02 0.02 0.03 0.03 0.03 0.03 0.04 0.04 0.04 0.04 0.04
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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Figure 2: FlexiCrane seen from the side. Approximately 1250 kg.
Figure 3: Close-up of loadcell showing 1370 kg.
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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Figure 4: One second after failure occurring at 1450 kg.
The upper hinge of module number 9, counting from the column, breaks. The crane stabilizes instantly at
approximately 550 kg, but the load was removed for safety.
Figure 5: Failure at Module no. 9.
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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Figure 6: Close-up of the failure point.
Figure 7: Lower hinge of module 9. This hinge alone supports 550 kg after failure.
SubC Partner A/S Kogade 1A DK-6700 Esbjerg www.FlexiCrane.com Phone: +4570232122 Mail: [email protected]
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All modules were disassembled and closely examined. All modules except number 9 were able to rotate
freely, showing no indications of any yielding.
Evaluation This destructive test showed that the design calculations are conservative as expected. The crane was
dimensioned to 330 kg, and failed at 1450 kg. This yielded a safety factor of the original design:
1450 𝑘𝑔
240 𝑘𝑔= 6.0
And a safety factor of the new design:
1450 𝑘𝑔
330 𝑘𝑔= 4.4
All the modules, except number 9, also secured that the modules will not yield at loads much higher that
maximum defined WLL. The modules could rotate freely even after failure of a module.
The test also shows that the FlexiCrane was able to withstand a very high load even after failure of the
module.
One could argue that introducing two Ø20.15 holes may reduce the strength of the module, however FEA
shows very little difference and that the hinges are still the most loaded area of the FlexiCrane.
