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Test, measurement and calibration laboratory

Measurements of the stress-deformed condition of the bridge through the channel


When extending water channels appears convenient opportunity for the measurement of the stress-strain states in the non-operation bridge. An experiment was conducted, whose task was to define stress in the upper connection points of supports. The load carried by hydraulic jacks, davivshimi on fixed anchors in the ground. A total of 416 LA11 10/120 strain gauges were connected to the half-bridge circuit using a cold curing adhesive X60 and protected by means of the spray hardens. The figure shows the location of the measurement points in the upper connection points of the supports, and also shows force sensors С6A to determine the effort and measuring amplifier MGCplus. This amplifier allows the connection of the following types of sensors:. Half- or full- strain gauges, inductive half or full- sensors, thermocouple, DC voltage source, constant current sources, etc. The amplifier allows flexible integration in control systems with the use of analog outputs, Ethernet, CANbus , ProfiBusDP.

Additional benefits: With the MGCplus amplifier possible to carry out static and dynamic measurements, and perform high-speed data transmission via Ethernet 100 Mbit.

Dynamic tension in the wheel suspension


Important safety components of automotive chassis components such as axles, require experimental verification of the force on the test bench. Such measurements are classified as the most difficult measurement tasks, since the measurement to be complicated multidirectional and dynamic stresses. The picture shows the test rig in which the steering knuckle car multidirectional subjected to dynamic loads. On the test object fixed gages such as sockets, which provide signals to the measuring amplifier MGCplus. An interesting feature of this fully computer-controlled system is that the voltage measured across multiple channels, completely synchronous in time because each measurement channel has its own amplifier with analog-to-digital converter.

Additional benefits: MGCplus amplifier allows simultaneous measurement across all channels, which is a feature necessary to solve this problem.

Static test model frame structures


For the purpose of check of static calculations for buildings of complex design, especially for buildings with unusual roof profile, are frequently used for measurement of stress-strain States in the large-scale models. The figure shows the model of the roof and the location of the load points. Models are made from fiberglass, fortified liquid resin, and have a complex shape. For the simulation of uniform load on the roof caused by, for example, snow requires a large number of points of load application. In one practical case was selected 900 points, which were subjected to a load by a system of levers. With the help of a quickly hardened adhesive Z70 models were fixed rosette strain gages of type 6/120 RY41. Instead of measuring apparatus used in the experiment, the figure shows the measuring amplifier MX1615 quantumx's series, which is widely used for measurements in experimental mechanics. The computer connection to an instrument amplifier significantly improves the valuation method and reproduce the results.

Additional features: MX1615 Measuring amplifier has 16 individually configurable inputs synchronized to connect chetvertfinalnyh, polnomochnykh or half-bridge strain gauges, voltage sources and resistance thermometers. The ability to power strain-gauge circuits DC voltage with a sampling rate of 19200 max. MEAs./channel (bandwidth of 3200 Hz) and AC voltage at the carrier frequency of 1200 Hz (bandwidth up to 400 Hz).

Wear resistance of rubber compounds

04-Износостойкость-каучуковых-соединений.pngFlexible couplings are made of rubber and metal are used to compensate for alignment errors in connected shafts. To test the fatigue limit of the rubber surface and curing should be tested. In this case, as shown in the figure, the inspected element is a flange rigidly attached to the base of a static torque sensor. Another connection element 30 rotates eccentric drive °, ie the rubber-metal portion of the compound is subjected to loads with continuous alternating torque. The torque sensor TB1 connected to the measuring amplifier MGCplus, which is connected to the computer via a digital output. The computer records the useful torque which amplitude is represented as an extreme value in numerical form or as a function of time. The measurement process is repeated in several time intervals so as to be able to assess any change in the net torque and hence to estimate the fatigue limit element.

Additional advantages: The compact performance torque sensor may be used in the test benches of simple construction. It is characterized by high accuracy and insensitivity to lateral and axial stress.

Extension of the measuring range for checking materials naprochnost mechanism

05-Расширение-измерительного-диапазона-механизма-по-проверке-материалов-напрочность2.pngThe mechanism for the checking of materials for durability force sensor together with other devices is responsible for the accuracy and the allowable measuring range. Previously, the sensor is embedded in the head rail. Now common method is to install force sensor Z4A a movable beam. This technique allows to create two workspaces, one for compression measurements, other measurements for stretching, not rearranging mechanism. In this case, the sensor occupies less space. Due to its flat design of the sensor is placed inside the mobile beams. Of course, it is desirable for the measurement of forces have a range as wide as possible. Because of the accuracy requirements of test mechanisms force measuring range should not be less than 10% of the sensor nominal force. The means to achieve this is the use of a second force sensor which is installed in a fastening device Z4A sensor and, depending on the rated load, the measuring range extends tensile forces repeatedly. For design reasons for this problem, we use U2A load cell/50kg, it can be calibrated as a force sensor.

Additional advantages: From the strain gauges and sensors to a multi-channel measuring amplifiers and software to solve problems of any complexity - range manufactured by HBM equipment covers the entire measurement chain.

Safety Check high-pressure hoses


High-pressure hoses before delivery should undergo a double test: test the gap and change volume under pressure. At a screening booth specifically designed for these tests, we tested eight hoses. Pressure Sensors РЗМB mounted on one end of each hose. Hoses are connected to the supply pipe through the solenoid valves. The test cycle begins with the launch of the feed pump and the inclusion (after closing the solenoid valves) high-pressure pump to create pressure in the test hose. Measuring amplifier MGCplus interrogates eight channels and transmits the data to the computer. Hose rupture is recorded due to an immediate drop in pressure. The change volume under pressure, i.e. tensile computer is detected during continuous cycle-accurate comparisons pressure in each hose. Since the hose is closed at both ends, the change in volume causes a decrease in pressure, which is detected by computer and outputted as an alarm.

Additional benefits: REM pressure sensor accuracy with the multi-channel measuring amplifier MGCplus enables the detection of a pressure drop in a very short period of time that allows you to optimize the entire test cycle.

Control strength in tunneling


When laying a railway tunnel under the tracks was used method of construction with side supports and the roof. He lay in piles driven in the side, and then the construction of the roof as a work of excavation. This allows to restore the normal motion at the surface in a short time. Due to the large dimensions of the tunnel (in this case 19 m wide, 24 m deep), the side supports are strengthened recessed anchors. The tensile forces in these anchors should be continuously monitored at certain points. During the works there was a large amount of evidence relative to the horizontal deformation and tilting of the side supports and the soil pressure on them. Anchor forces working on the lateral support via built force sensors C6A/2000кН. Due to the large distance measurement cables were not connected to the control station, and instead leads to the connection panel, which is located near the individual groups of anchors. Measurement of anchor forces carried out at certain time intervals by measuring amplifier powered by a rechargeable battery.

Additional benefits: C6A force sensor is insensitive to eccentric loads, which are inevitable when using a sensor in a tunnel lining.

Experimental analysis of stresses in the blades of the model ship's propeller


Screws with a crescent-shaped blades are widely used because they produce less noise and vibration. Strength calculation in this case is very complicated, and we have to use measurements of stress on models. The figure shows the screw model and the location of measurement points on the suction side and ejection. The test was conducted in a wind tunnel. Signals transmitted to the strain gauge amplifier by means of a sliding contact ring disposed in the shaft cavity. In this case, we use a measuring amplifier MGCplus. It allows completely synchronous receive and immediately digitize the signals on all channels. This feature is essential for dynamic measurement of stress - when needed reliable results.

Additional advantages: MGCplus can be used in conjunction with DC voltage amplifiers or carrier. In the case of sliding contact rings it is recommended to always use the carrier frequency amplifiers, because they help to eliminate the effect of thermoelectric voltages caused by sliding contact rings.