MCCT LABORATORY
Mechanical and Climatic Calibration and Testing Laboratory
SERVICES - TESTING
A. Tests to determine the elastic characteristic of controlled deformable elements
Reference documents:
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NTF 67-001:2006 – Railway vehicles. Technical requirements for the planned overhaul and repair of the 2,100 hp diesel-electric locomotive;
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NTF 67-003:2008 – Railway vehicles. 5,100 kW and 3,400 kW electric locomotives. Technical requirements for planned overhauls and repairs;
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NTF 82-002:2004 – Railway vehicles. Collision, traction and tying devices. Repair technical requirements;
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OMT 410:1999,on the authorization of testing laboratories and testing of stands and special devices for the verification and testing of railway products used in the construction, modernization, operation, maintenance and repair of railway infrastructure and rolling stock, specific to rail and subway transport;
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SR EN ISO/CEI 17025:2018 – General requirements for the competence of testing and calibration laboratories;
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EA-4/02 M: 2013 – Evaluation of the Uncertainty of Measurement in Calibration.
Locomotive Spring Testing - Testing the coil springs of the secondary suspension
Functional description:
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The stand is intended to determine the force-deformation (FS) characteristic of the helical springs in the secondary suspension of the VF. Springs may be tested separately as outer spring/inner spring elements, or may be tested as an outer spring and inner spring assembly.
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The stand consists of a sheet metal platform with a thickness of 25 mm and dimensions of 700 x 800 mm, on which the helical springs are mounted. The springs are centered below and above by circular centering elements, identical to those on the locomotive. At the top there is a platter with six pairs of circular ball bearings that slide on six 40mm diameter tie rods made of high quality spring steel. A 200kN, class 0.5 circular dose is mounted above the plate.
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The pressing force is achieved by means of a high-precision hydraulic cylinder, Enerpac, type RC1510, with the following characteristics: maximum stroke 254 mm, maximum force 150 kN, maximum pressure 700 bar, effective surface of the cylinder 20.3 cm2.
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Hydraulic pressure is provided by a high-pressure oil pump at 700bar, which allows setting in pressure steps with an error of 5bar. In automatic operating mode, the pump automatically maintains the imposed pressure within the range of two imposed limits, upper and lower.
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To determine the FS characteristic, the nominal force range of coil springs is divided into 5 sub-ranges, resulting in 5 test force steps, in the range 0…Fn.
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At the beginning of the actual loading cycles, the initial spring length is measured using a metrologically verified caliper.
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The test itself consists of the application of three sequences of 5 levels of strength: 0; 1/5Fn; 2/5Fn; 3/5Fn; 4/5Fn; Fn; 0. On each force level, the load is kept constant for a duration of approx. 20s. For each load-unload cycle, the compressive force and spring deformation are recorded. From the representation in FS coordinates, the elastic constant, k of the springs is determined , this is used to pair them, in order to obtain the most uniform distribution of the load on the bogie frame and the locomotive casing.
Metallastic tests - Testing the metallasts of the primary suspension
Functional description:
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The stand is intended to determine the force-deformation (FS) characteristic, in the vertical direction, for the metallic rubbers in the primary suspension composition of the VF, with three and five rubber packs.
The stand consists of a U-shaped frame in which the metal elastic is attached in conditions similar to the attachment on the bogie. The sliding part of the metallastic, which in the original assembly is attached to the axle bearing, is fixed by a vertical sliding carriage that can move without friction on two guide rails.
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The pressing force is achieved by means of a high-precision hydraulic cylinder, Enerpac, type RC1510, with the following characteristics: maximum stroke 254 mm, maximum force 150 kN, maximum pressure 700 bar, effective surface of the cylinder 20.3 cm 2 .
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A force transducer, HBM – S9M-50kN, is interposed between the carriage and the cylinder piston.
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The vertical travel of the metal elastics is measured with a linear travel transducer, HBM, type W200.
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To determine the force-deformation characteristic, the nominal force range is divided into 5 sub-ranges, in the range 0…Fn, resulting in 5 test forces.
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The test itself consists of the application of three sequences of 5 levels of strength: 0; 1/5Fn; 2/5Fn; 3/5Fn; 4/5Fn; Fn; 0. On each step of force, the load is kept constant for a duration of 10s. For each load cycle of records downforce and stroke.
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From the representation in force-deformation coordinates, the elastic constant, k, of the metal elastics is determined, this serves to pair them, in order to obtain the most uniform distribution of the load on the bogie frame.
Testing the shock absorber of the railway vehicle coupling device
Functional description:
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The stand is intended to determine the FS or FV (damping force-stroke or damping force-velocity) characteristics of hydraulic and friction dampers, in particular those that equip railway vehicles, including locomotives and electric frames.
Shock absorbers are tested in the horizontal position.
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The test stand consists of a drive module, equipped with an electric motor type ME160-L4-B5-15KW/1500RPM that drives a mechanical reducer type A602-UH60-7.9-P160, obtaining at the output a nominal speed of 3.16 Hz. The rotational movement is transmitted to a flywheel that actuates a connecting rod whose free end performs a translational movement imposed by a linear guide system consisting of slide rails type TKD35-G3-HJ600mm and linear carriages type KWE35-G3-V1.
The linear stroke is obtained from the rotational movement of the flywheel, on the principle of the connecting rod-crank mechanism, the crank arm being adjustable, in the range of 0÷200mm.
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The high forces involved in this kind of testing require the use of a 1MN force transducer, which is very expensive and very difficult to handle. This is the reason why in this type of tests the measurement of traction or compression forces is done by indirect methods.
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The deformation of the elastic elements is measured with a linear stroke transducer, HBM, type W200.
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To determine the force-deformation characteristic, the nominal force domain of the deformable element is divided into 5 subdomains, resulting in 5 stages of test forces, in the range 0…Fn.
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The test itself consists of the application of three sequences of five levels of strength: 0; 1/5Fn; 2/5Fn; 3/5Fn; 4/5Fn; Fn; 0. On each force level, the load is kept constant for a duration of approx. 20s. For each load cycle the force and stroke are recorded. From the force-deformation graphic representation, the elastic constant, k, of the elastic element (if applicable) is determined.
Testing the Pads for the locomotive - Trying tampons
Functional description:
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The stand is intended for the determination of the force-deformation characteristic of the controlled deformable elements of the railway vehicles (pads, shock absorber of the binding device, binding device). The stand consists of a sheet metal platform with a thickness of 50 mm and dimensions of 900 x 600 mm, provided with two lateral arms of I500 with a length of 1650 mm.
Between the two sides of the I500 slides a sheet metal plate with a thickness of 50 mm and dimensions of 610 x 460 mm on which is mounted a high-precision hydraulic cylinder with a drilled piston, Enerpac, type RCH606, with the following characteristics: maximum stroke 156 mm, maximum force 576 kN, maximum pressure 700 bar, effective cylinder surface 82.3 cm 2 . The displacement of the cylinder is done with an increment of 10 cm.
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The center bore piston allows the same cylinder to be used for both tension and compression forces. The element to be tested is placed in the lower part of the cylinder.
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The high forces involved in this kind of testing require the use of a 1MN force transducer, which is very expensive and very difficult to handle. This is the reason why in this type of tests the measurement of traction or compression forces is done by indirect methods, measuring the pressure in the cylinder chamber and using the calculation relationship.
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When using the indirect method, by measuring pressure, precautions must be taken regarding the time to reach dynamic equilibrium between pressure, volume and temperature, the three quantities being interdependent. A time of at least 20s must be waited for a load force step.
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The deformation of the elastic elements is measured with a linear stroke transducer, HBM, type W200.
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To determine the force-deformation characteristic, the nominal force domain of the deformable element is divided into 5 subdomains, resulting in 5 stages of test forces, in the range 0…Fn.
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The test itself consists of the application of three sequences of five levels of strength: 0; 1/5Fn; 2/5Fn; 3/5Fn; 4/5Fn; Fn; 0. On each force level, the load is kept constant for a duration of approx. 20s. For each load cycle the force and stroke are recorded. From the force-deformation graphic representation, the elastic constant, k, of the elastic element (if applicable) is determined.