The method for determining the deformation of structures under test conditions alternating thermal stresses, and a sensor for detecting the deformation
(57) Abstract:The invention relates to measurement techniques, in particular to methods and devices for determining the deformation of the airframe. The aim of the invention is to improve the accuracy of determining the deformation of structures under test conditions alternating thermal stresses. The strain sensor includes testcustomer element 3, the heating element 6 and the sensing element 7 connected to the switch 11 and a transmitter 12 of the measuring path. When implementing the method of the strain sensor mounted on the test structure, connects the measuring instrument, perform functional calibration and calibration of the measuring path. The sensor is subjected to thermo effect, feeding from the transducer 12, the current pulse given power to heating element 6, measure the resistance of the sensor signal of the strain-sensing element 3. Subjected to the test design disposable force loads and additionally measure the resistance of the sensor. The deformation of the structure is determined by the dependence of weather resistance is Z. p. f-crystals, 2 Il. The invention relates to measurement devices, and in particular to methods of determining the mechanical deformation of structures, structures strain of the strain gauges, as well as methods of monitoring their health, and can be used to determine the deformations of objects, work under alternating thermal stresses in a long time operation.Known  a method for determining deformation of structures under alternating thermal stresses, namely, that connected in the bridge circuit of the strain gages installed on the structure, with one or two load cells measure the deformation, as workers, and three or two not perceive deformations from ekspluatatsionnykh loads, but are subject to deformations alternating temperature stresses, as compensation. At the output of the Normalizer connected to tanzamomo, remove the signal which is proportional to the deformation of operating loads.The disadvantage of this method is inaccurate determination of transfer function of tentmate for an extended period of research or the operation of the object, t is the quality of the strain gauge, which vary with time and operating conditions of the object.A known method of controlling the quality of the bonding of the strain gauge , based on the supply of the pulse current in the wire strain gauge (DMS, measuring changes in the resistance and compare it with the change of the reference resistance of the strain gauge pasted.Known  the method of controlling the quality of the bonding of strain gages by filing a current pulse of a selected duration considering the fact that the heat flow does not have time to come and spread to the surface of the object.The disadvantages of the known methods of control are;
supply current pulse of increased amplitude in testcustomer grating sensor that can lead to device failure and achieved little effect its linear expansion due to thermal stabilization of grating material;
comparison of measurement results with indications of control sensors during operation still need somewhere to install and connect;
the lack of availability of functional calibration of the whole path of the measurement (sensor measuring track-measuring transducer-recorder).The most effective is the governance of deformation.The strain gauge includes two blade supports, the meter movement in the form of a bracket mounted on it testcustomer and thermosensitive elements, thermostable rod with insulating spacers at the ends connected to the free end of the bracket, the temperature compensating rod with a fixed heating element. The temperature compensating rod at one end through a lining connected with thermostable pivot and at the other end through the strip - blade prop.The strain sensor mounted on the structure by means of knife supports, mounted on the bracket. Connects the measuring instrument. Before determining deformations produce functional calibration or calibration of the entire measuring path, which provides high accuracy measurements. The calibration carried out by thermo-impact, connecting the voltage to the heating element of the sensor, which causes to increase the temperature compensating rod, thus providing a given deformation of the bracket and accordingly placed the strain gauge.After achieving equal stages increment predetermined temperature, measure the resistance datti its resistance against thermo effects, made in the calibration.The proposed method of measurement and sensor deformations can improve the measurement accuracy by eliminating systematic errors in the measuring path.However, the sensor due to the complicated and cumbersome mechanical structure, its thermal and mechanical inertia, the unreliability of its mounting supports cannot provide with long-term quasi-static loads under alternating thermal stresses required accuracy of strain measurement.The disadvantage of this method of strain measurement is the low accuracy of determination of the relationship between calibration characteristics obtained when the power and thermo loading.The aim of the invention is to improve the accuracy of determining the deformation of structures under test conditions alternating thermal stresses.The goal for the method is achieved in that in the method of determining the deformation of the structure during the tests under alternating thermal stresses, namely, that on the test design set, a strain sensor strain, ovcu just measuring path, a strain sensor is subjected to thermo effect by connecting voltage to its heating element, measure the resistance of the sensor and determine the deformation of the structural dependence of the sensor resistance values of thermo effects, additionally subjected to the design of the disposable force loads and additionally measure the resistance of the sensor and the deformation of the structure is determined taking into account the dependence of the sensor resistance values of force operational loads.The goal is for the device is achieved in that the sensor for detecting the strain containing testcustomer element with an insulating substrate for mounting to the test structure and the heating element, provided with a heat-conducting plate and a thermosensitive element, the plate is installed in contact with testcustomer element, and thermosensitive heating elements are installed on the plate.When applying pulses of current to the heating element, mounted on the plate, testcustomermap grating sensor is experiencing stress arising from complex Hermosillo the Oia, moreover, thermo effect is determined by the linear extension plate and heat flow in the structural elements of the sensor, this causes deformation equal to deformation from forces acting on the structure during operation.Identifying the measurement results from thermo effects with once carried out by the measurement results in a stepwise calibration loading design and making a correction for the temperature increment receive a calibration and functional characterization of the entire measuring system path.In Fig. 1 shows a strain gauge, a General view of Fig.2 - scheme of the measuring path by using a strain gauge.The strain gauge (Fig.1) contains wire strain gauge (DMS installed on parts 1 and manufactured by winding with a toner to the substrate 2 of the strain-sensing element 3 from Terzopoulos and closing its shell 4 from that of the binder.On comisariada the gasket 5 is installed, the heater element 6 a lattice-type and temperature-sensitive element 7 is also a lattice-type, which are located outside vivogenerated extensions as experience design. For example: the heating element 6 can be produced by etching of Constantan foil and the sensing element 7 by etching of the copper foil deposited on a substrate of glue VL-6 and then pasted on the plate 9.Measuring the tract containing the strain sensor includes a temperature sensitive element of the sensor 7, two conclusions which on the one hand through the measuring route 10 go to the switch 11, and on the other hand is on the switch and on sensorised 3, the second terminal through which the measuring track 10 goes to the switch 11 and to the first input of the heating element 6, the second output of which is connected to the measuring track with the switch, the output of which is connected with the measuring transducer 12, one output of which is connected with the recorder 13, and the other with the switch.The transmitter 12, the feeding current pulse of a given power to the heater 6, measures the signals from the strain gauge 3 about the change in its resistance when heated for further calculations on the basis of the calibration characteristics with temperature correction.The duration of heating of the strain gauge, the magnitude of the heating current is the value with the magnitude of the deformation of the structure during its power loading.In this case, when the wire strain gauge (DMS made of Constantan wire with a thickness of 0.03 mm, substrate binding and membrane from the glue VL-6, a plate made of aluminum foil DM, heating elements made of Constantan foil, heat-sensitive element of the copper foil, a current pulse is equal to I=200 mA and has a duration of not more than 1 sec.The method of determining the deformation of the structure during testing or operation under alternating thermal stresses is implemented by the following sequence of operations:
on the test design set, a strain sensor strain; connects the measuring instrument, perform functional calibration or calibration of the entire tract, with a strain sensor is subjected to thermo effect by connecting voltage to its heating element and measure the resistance of the sensor. Put the design disposable force loads and additionally measure the resistance of the sensor. The deformation of the structure is determined by the dependence of the sensor resistance values of thermal and force of impact and the force impact of operational nagrazhdennyh VOLTAGES AND the SENSOR FOR detecting the DEFORMATION.1. The method for determining the deformation of structures under test conditions alternating temperature stresses, namely, that on the testing set design, a strain sensor strain, hook up equipment, prior to testing, perform functional calibration of the entire measuring path, a strain sensor is subjected to thermo effect by connecting voltage to its heating element, measure the resistance of the sensor and determine the deformation of the structure by the dependence of sensor resistance values of thermo effects, characterized in that, to improve accuracy, optionally subjected to the design of the disposable force loads and additionally measure the resistance of the sensor, and deformation of the structure is determined taking into account the dependence of the sensor resistance values of force operational loads.2. A sensor for detecting the deformation of structures under test conditions alternating temperature stresses containing testcustomer element with an insulating substrate for mounting to ispycoupons plate and a thermosensitive element, plate set in contact with testcustomer element, and thermosensitive heating elements are installed on the plate.3. The sensor under item 2, characterized in that the heating element is designed as a grid of high-resistance material.4. The sensor under item 2, characterized in that the sensing element is made in the form of a lattice of heat-sensitive wire.
FIELD: testing engineering.
SUBSTANCE: device comprises high-frequency generator and inductor connected in series, device for control of heating, system for air supply, device for external cooling, measuring system, unit of contact temperature gauges, and device for bottom clamping connected with the end section of the blade. The device is provided with a means for axial loading, device for top clamping connected with the shelf of the end section of the blade, device for control of axial loading, first dynamometer, device for applying torque, which has the second dynamometer, device for information input, load-bearing frame, contactless temperature gauge, generator of nonstandard signals, oil pumping system, and device for internal cooling.
EFFECT: enhanced reliability of testing.
7 cl, 1 dwg
FIELD: measuring technique.
SUBSTANCE: method comprises heating the heat-shield structure from one side up to a high temperature, cooling the structure, applying marker dots on the section of the outer surface under study, cutting the axisymmetric specimens of the heat-shield structure, applying marker dots on the side of the specimen at a given distance from the inner surface, cutting the specimen over the planes perpendicular to its longitudinal axis and passing through the marker dots into pieces, subsequent heating of the pieces in the atmosphere of an inert gas, recording the change of weight of the pieces, recording the temperature of the beginning of the decrease of weight of each piece, and judging on the spatial temperature distribution from data obtained.
EFFECT: expanded functional capabilities.
SUBSTANCE: stone sample saturated with water is frozen to a specified temperature. The sample is unfrozen and deformation is measured. Before freezing, the threshold load which accounts for long-term compression strength of the sample is measured using a nondestructive method. After several thermal cycles, residual deformation of the unfrozen sample is measured in the direction perpendicular the previous compression. A least residual deformation is achieved through periodical compression of the sample in the current direction from zero to a load which exceeds the threshold by not more than a third. The number of thermal cycles required for reducing long-term strength to the required value is determined by repeating these operations.
EFFECT: reduced labour input and increased efficiency.
SUBSTANCE: method of determining heat resistance of bentonite clay is characterised by that, a nomograph which reflects dependency of temperature of the second endothermal effect and heat resistance of bentonite clay from contained structural iron is constructed first. For this purpose samples of bentonite clay from known deposits are analysed. The samples are tested in a derivatograph. Derivatograms with differential thermo-weighted (DTW) and differential thermal (DT) curves are obtained, from which temperature of the second endothermal effect is determined depending on structural iron contained in the samples. Heat resistance of the samples is determined depending on structural iron contained in the samples. From the said two curves, the said nomogram is constructed, which is then used for subsequent determination of heat resistance of the analysed bentonite clay; a wet ground up sample is tested in a derivatograph by heating followed by drying. Derivatograms with differential thermo-weighted and differential thermal curves are obtained, from which temperature of the second endothermal effect is determined and heat resistance of the analysed bentonite clay is determined from the said nomogram.
EFFECT: cutting on time and simplification of the process of determining heat resistance.
SUBSTANCE: device has a cylindrical housing, a horizontal partition wall and sensors for monitoring and controlling tests. Inside the cylindrical housing, which has a flat bottom and an air-tight cover which is fixed by bolts and nuts in the top part, there is a drum which is mounted on the cover inside the housing. The horizontal partition wall is placed in the bottom part of the drum and is in form of a perforated disc whose perforations are in form of calibrated orifices lying on a circle, having along their edge calibrated channels for passage of heating medium. Inside the drum there is an additional horizontal partition wall with calibrated orifices which are exactly as those in the perforated disc. Sample pipes are fitted in the perforations of the disc and are fixed on the cover of the housing, and there are vertical partition walls between the pipes. Pipes with a smaller diameter are fitted inside each sample pipe and are fixed in a dispensing receiver and have in their top part connecting pipes for outlet of cooling medium and discharge pipes with calibrated devices on them. In the bottom part of the housing under the perforated disc there is a pipe with a diffusion nozzle connected to a cylindrical diffuser and a connecting pipe for inlet of heating medium and a system of chambers with a connecting pipe at the bottom for outlet of the heating medium.
EFFECT: high quality and accuracy of tests and efficiency thereof.
SUBSTANCE: invention relates to space hardware testing, namely to installations for simulation of spacecraft components operation modes. Installation for vacuum thermocycling of photoconverter panels includes vacuum chamber consisting of two communicating compartments. In one compartment, two cryopanels are installed in parallel with possibility to place tested panel between them. In the second compartment there is thermal panel made as assembly of filament lamps. The cryopanels and thermal panel are positioned vertically, and thermal panel compartment is placed over cryopanel compartment. The cryopanels are installed with possibility of additional placement of thermal panel between them. The thermal panel is provided with reciprocating mechanism of vertical action and thermal insulation at the side facing cryopanel.
EFFECT: higher accuracy of thermal simulation of outer space conditions.
3 cl, 4 dwg
FIELD: testing equipment.
SUBSTANCE: device comprises a body with a flange joint and tested samples in the form of tubes. Tested samples in the amount of two arranged coaxially one inside the other to form a circular gap between them, are fixed inside separate parts of the body, placed on a header of hot water and a header of drainage of a mixture of hot and cold water. Headers by means of pipelines are connected to a heater and a refrigerator. The outer surface of the outer tube and the inner surface of the central tube are coated with a layer of insulation. In the upper part of the body there is a nozzle and a valve for supply and control of cooling water flow.
EFFECT: elimination of medium working pressure impact at process of crack formation, providing for pure crack formation only due to pulsation of medium temperature, which results in getting absolutely accurate testing results.
FIELD: test equipment.
SUBSTANCE: stand includes base, coaxial sample grips mounted on the base, sample loading device connected to the grips, mechanical sample processing device and platform for processing devise movement against grip axes. Additionally the stand features aggregate for grip turning around grip axis, consisting of drive with two gear wheels bearing the grips, on the drive shaft.
EFFECT: extended functionality of stand due to test performance at changing directions of mechanical processing against radial directions of sample.
FIELD: testing equipment.
SUBSTANCE: invention relates to testing equipment, to tests of mostly samples of rocks. The bench comprises a base, sample grips installed on it coaxially, a device to load a sample with an axial mechanical load, a mechanism for interaction with the sample, a platform for movement of the mechanism along the axis of the grips, a platform for movement of the mechanism in the vertical direction perpendicularly to the axis of the grips and a platform for movement of the mechanism in the horizontal direction perpendicularly to the axis of the grips. The mechanism for interaction with the sample is made as milling.
EFFECT: expansion of functional capabilities of a bench by provision of research with gradual removal of material sample without removal of mechanical load.
FIELD: test equipment.
SUBSTANCE: device includes gas generator and operation part with structural material sample, connected in series. Gas generator features removable mixing head. Cylindrical combustion chamber of the gas generator features ignition device and orifice plate. Operation part includes interconnected clamping flange with central hole and flange holding a sample. Central longitudinal axes of flange and sample are coincident. Internal cylindrical surface of clamping flange forms an annular slot with the sample surface, the slot joins a cavity ending with output nozzle through end outlet holes in the flange around sample.
EFFECT: possible maintenance of required pressure-heat loading modes for samples, modelling natural thermal stress state of structural materials of various aggregates operating in alternate heat modes.