Method of determining deformation characteristics of polymeric material
FIELD: light industry.
SUBSTANCE: method comprises recording response of the material to be tested that represents an amplitude-frequency characteristic, calculating deformation characteristics, and determining the value of distributed mass of the vibrating part of the material. The response representing two amplitude-frequency characteristics is recorded for the same part of the material to be tested for various masses of two bodies that cause deformation. The deformation characteristics are calculated from equations of vibration theory for viscoelastic bodies.
EFFECT: enhanced precision and reliability.
The invention is related to light industry, in particular to methods allowing to determine the stiffness, the value of the viscous friction, the tangent of mechanical loss polymeric materials in a resonant mode.
Known methods of determining the modulus of rigidity in bending /Meredith R. and J., Vshare. Physical methods of research of textile materials. - M.: Gisleham, 1963, str/.
This work presents methods of excitation of transverse oscillations of the fiber and the relationship definitions of the modules of rigidity E1and loss of E2in the form:
where I is the moment of inertia of the cross-section sample, Δv - width of the resonance curve, ν resonant frequency.
This method causes difficulties when calculating module E1and E2due to the complexity of the calculation of moment of inertia I of the cross section of the sample or the amount distributed mass.
The closest analogue of the claimed invention is a method of determining the mechanical properties of leather for the uppers /A.S. USSR №1000910, CL. G01N 33/44, 1981/. This method involves the application to the studied sample skin sinusoidal changing frequency force pressure load and recording the amplitude of the sample and the half width of the resonance curve of the amplitudes of the on-frequency characteristics and the subsequent evaluation of mechanical properties. Sinusoidal load attached to the front surface of the sample of the skin, placed on the unyielding ground. The calculation of the indices produced by the following dependency:
where σ - breaking the tension, ε strain at break, ν resonance frequency, Δν - width of the resonance curve, 1 - thickness of the specimen.
The disadvantage of this method is the bias of the conducted calculations, since the cut-off voltage in polymer materials is fluctuating in nature and not related to linear elasticity, which represents the amplitude-frequency characteristic. Besides the permanent members of the equalities are empirically selected coefficients.
The aim of the invention is to improve the accuracy and reliability of the method for determining the deformation performance of viscoelastic materials.
This objective is achieved in that the method of determining the deformation performance of polymeric materials is determined by application to the studied material sinusoidally varying force action, the registration response response of the investigated material in the form of amplitude-frequency characteristics, an additional determination is elicina distributed mass oscillating part of the material and the registration response response in the form of two amplitude-frequency characteristics for the same topographical area of the studied material at different the masses of two bodies, causing deformation, and deformation calculation of the indicators according to theory of oscillations of viscoelastic bodies with one degree of freedom in a region of linear viscoelasticity.
This theory considers the oscillatory processes of a small mass under the influence of periodically varying power impacts with the force of friction. The use of theory of oscillations allows to obtain a range of deformation performance of polymeric materials. The complexity of the practical use of the method of resonance testing is difficult to determine the moment of inertia or the amount distributed mass Δm oscillating part of the investigated material.
The author of the present invention developed a method of determining the value of the distributed mass Δm oscillating part of the material under various types of deformation. It is known that any mechanical system with mass m and stiffness k, has its own resonant frequency ω0which is expressed by the relation:
For our particular case this ratio will be:
where m1well - known mass attached to the material studied under various types of deformation, or body weight, environmenta is found on the investigated material. If a large mass m1to replace several smaller mass m2then the self-resonant frequency ωp.1change its value in a big way and will be equal to ωp.2. With the rigidity of the studied material will not change, and the stiffness coefficient in this case is determined by the equation:
Then the right hand sides of equalities (4) and (5) are equal, ie,
Thus, by determining the value of the resonant frequencies ωp.1and ωp.2when the respective masses m1and m2it becomes possible to determine the value of distributed mass Δm oscillating part of the investigated material.
Using theory of oscillations of a viscoelastic body in the linear region of the strain off of the amplitude-frequency characteristic of the investigated object, it is possible to find the following indicators:
the stiffness coefficient k
the total mechanical resistance z, acting from a deformable material
which in the case of resonance becomes equal to the value of the coefficient of viscous friction g, as the elastic component of the k/ω and inertial resistance Δmω the mill is become equal quantities and vzaimodeystviya.
The tangent of mechanical loss tgϕ
where β - attenuation factor equal to
q material Q
where Δω - width of the resonance curve at the level of 0,707, xRSthe amplitude of the deformation at resonance, Xarticle- deformation of the material during the ω=0, i.e. static deformation under the influence of a constant force F0.
The relaxation time of the material τshowing the time interval for which the amplitude of the deformation decreased in e times.
the modulus of elasticity E1and the loss modulus E2the energy expended in overcoming the forces of viscous friction, and other important deformation parameters.
From the above analysis it follows that all of the above deformation indicators can be obtained at the various types of deformation under the condition of imposing an oscillatory process of the same material of the two largest known additional mass and receiving two corresponding and amplitude-frequency characteristics.
The difference of the proposed method from the method, taken as a prototype, is that in the proposed method, removed two amplitude-frequency characteristics for the same topographic teaching the TKA at different body masses, causing oscillatory movement of the investigated material that assures high precision and reliability to detect a range of deformation performance of polymeric materials and the finished structures of products of light industry.
The method of determining the deformation performance of polymeric materials by application to the studied material sinusoidally varying force action, the registration response response of the investigated material in the form of amplitude-frequency characteristics and calculation of the deformation parameters, characterized in that it further determine the magnitude of the distributed mass of the oscillating part of the material, while the registration response response in the form of two amplitude-frequency characteristics of the produce for the same topographic portion of the study material for various masses of two bodies, causing deformation, and the deformation calculation of indicators carried out according to theory of oscillations of viscoelastic bodies with one degree of freedom in a region of linear viscoelasticity.
FIELD: weighing equipment; chemical mechanical engineering.
SUBSTANCE: method can be used for measuring content of binder in reel-up composite material produced by preliminary soaked thread. Method is based upon weighing. The constant values are determined according to the method as length of thread for specific type of items and value of linear density averaged for any reel before and after soaking by binder and reeling it up onto frame. Weighing is performed for item before reeling it up with soaked thread and after reeling-up and final polymerization of composite material to determine mass of composite. Basing upon the data received, content of thread is determined which value is subsequently used for finding mass content of binder in composite from relation of C=(M-LxT/M)x100%, where C is content of binder in composite, in mass percent; M is mass of composite, g; L is length of thread consumed for item, km; T is average arithmetic meaning of values of linear density of thread and its rests at any reel before and after impregnation, g/km.
EFFECT: higher stability of performance measures.
FIELD: investigating or analyzing materials.
SUBSTANCE: method comprises preparing specimens of polymeric materials of specified mass, exposing the specimens to the hostile fluid at a given temperature, and determining informative characteristic from a formula proposed.
EFFECT: enhanced reliability.
2 dwg, 7 tbl, 2 ex
FIELD: technologies for researching durability properties of packing washer materials for collapsible oil pipelines.
SUBSTANCE: in the method for determining remaining resource of rubber compacting curves utilized in oil pipeline junctions, preparation of samples of given geometrical shape is performed, measurement of source hardness conditions for stretching, relative elongation during tearing, Shore hardness, temperature fragility limit, comparison of aforementioned values to given values, culling of washers, sample coefficients of which do not correspond to given values. Remaining samples are exposed to oil product after extraction from oil product samples are thermostatted, cooled down to normal room temperature, and then the same physical-mechanical coefficients are measured again with limit values. Before preparation of samples with given geometrical shape, washers are organized in batches of same manufacturing plant and production year, additionally measured are external d1 and internal d2 washer diameters for each batch, relative compression Ecp deformation of same washers. Their deviation from standard is calculated and culling of aforementioned washer batches is performed on basis of allowed values Δd1, Δd2 and Ecp, while as allowed values Δd1, Δd2 ≤ 3%; 25% ≤ Ecp ≤ 70%. After that remaining rings with least values of relative compression deformation Ecp are utilized to prepare geometrical samples of given geometrical shape. Remaining resource ΔT is determined from following formula: years, where ki - coefficient, characterizing alteration of remaining resource ΔT dependently on climatic zone input of operation of rubber packing washers, is taken as i - climatic zones I1 - II12, additional information, T - average lifetime of rubber packing washers until removal from operation in accordance to technological characteristics provided by manufacturing plant and/or operation instructions, in years, Tn - period of operation of rubber packing washers since production year - marking of manufacturing plant, until moment of determining ΔT, years, fpδ=9,4 MPa - minimally allowed value of conditional hardness for stretching after thermostatting of sample, MPa.
EFFECT: reliable trustworthiness of results of estimation of remaining resource under dynamic conditions of rubber packing washers in oil pipeline junctions with simultaneous increase of ecological safety due to decreased risk of emergency spilling of oil products.
FIELD: agriculture, in particular, dairy farming.
SUBSTANCE: method involves determining tightening of teat cup liner before it is inserted into teat cup; acting upon teat cup liner by suspending weight for determining tightening of teat cup liner; providing expansion by introducing internal gauge into teat cup liner which is positioned within teat cup casing. Method allows extent of teat cup liner tightening to be visually detected at any time of machine milking process. Tightening of teat cup liner manufactured integral with milk pipe as well as separately therefrom is determined during operation of milking units.
EFFECT: increased efficiency and reduced milking time.
FIELD: methods and devices for determination of an alcohol concentration in solutions.
SUBSTANCE: the invention presents a method of determination of an alcohol concentration in solutions (versions) and a device for its realization (versions). The first version of the method provides for placement of a bath with the reference and investigated solutions on the path of the optical beam, measuring and introduction into the memory of the computation unit of intensity of the light absorption by the reference solutions, measuring of the intensity of the light absorption of radiation of the investigated solution, processing the data of the measurements of the light absorption. The investigated solution is transilluminated within the range of the wavelengths of 1250-1350 nanometers. Simultaneously with the measurement of the light absorption by the investigated solution measure the concentration of alcohol in it. In compliance with the received values determine a concentration of alcohol in the investigated solution. The second version of the method provides for placement of a bath with the reference solutions and investigated solutions on the path of the optical beam, measurement and introduction into the memory of the calculation device of intensity of the light absorption of radiation by the investigated solution, processing of the received values of the measurements of the light absorption. The investigated solution is transilluminated within the range of the wavelengths of 1250-1350 nanometers, measure the values of density of the reference solutions and the investigated solution, using which determine the concentrations of alcohol and sugar in the investigated solution. The device for the first version contains a computation unit, a conjunction unit, optically coupled a radiating unit, a bath for solution, a measuring photoreceiving device, the output of which is connected through the conjugation unit with the computation unit and the input of which is optically connected through the bath with the radiating unit. The device for measurement of a concentration of sugar in a solution consists of a beam splitter plate and an additional photoreceiving device, the output of which is connected through the conjugation unit with the computation unit. The input of which is optically connected through the beam splitter plate mounted at Brewster's angle to a axis of radiation and the bath with by a radiation unit. And the radiation unit has the wavelength of radiation laying within the range of 1250-1350 nanometers. The device for determination of a concentration of alcohol in the solutions consists of the computation unit, the conjugation unit, the optically connected radiation unit, the bath for solution, the measuring photoreceiving device, output of which is connected through the conjugation unit with the computation unit, the density gage connected with the bath by means of the pipe duct. The output of the density gage is connected through the conjugation unit with the computation unit. The radiation unit has the wavelength of radiation laying within the range from 1250 to 1350 nanometers. The invention allows to improve accuracy of measurements.
EFFECT: the invention ensures an improved accuracy of measurements.
12 cl, 5 dwg
FIELD: fur industry, in particular, method for evaluating pickling quality of leather web in tanning of fur and sheepskin raw material.
SUBSTANCE: method involves determining quantitative pickling characteristic of leather web of semi-finished product by using time of solving thereof in alkaline solutions, said time depending on number and kind of intermolecular bindings destructed during pickling. Solving of collagen in alkaline solutions depends upon nature of preliminary acidic preparing procedure. Solving is provided in aqueous solution of potassium hydroxide having concentration of 150 g/l and temperature of 18-20 C. Derma solving time is found after preliminary thermal processing at temperature of 60-65 C during 1.5 hours. Method may be employed both in production of fur and sheepskin products and in fur processing.
EFFECT: wider operational capabilities and reduced time for determining quantitative pickling characteristic of skin web.
1 tbl, 1 ex
FIELD: fur industry, in particular, method for evaluating pickling quality of leather web in tanning of fur and sheepskin raw material.
SUBSTANCE: method involves providing testing on parallel groups of fur sheepskin after pickling on three topographic portions of sheep skin surface: skirt, spine and neck portions; processing samples of each group with acid-salt solution for 24 hours; withdrawing sheepskins of each group from acid-salt solution in predetermined time intervals; removing excessive liquid; placing said samples into tensile testing machine and stretching lengthwise of spine line by 40% relative to initial length thereof; holding samples in stretched state for 1 min and withdrawing from tensile-testing machine; leaving samples in free state for 10 min; determining residual elongation value in mm.
EFFECT: reduced time for determining quantitative pickling characteristic of skin web.
2 tbl, 2 ex
FIELD: the invention refers to measuring technique namely to modes of testing materials in particular of asphalt concrete and organic-mineral mixtures on fatigue at cyclical dynamic impacts.
SUBSTANCE: the mode of evaluation of fatigue of asphalt concrete at cyclical dynamic impacts includes fastening of the sample, weighting of a cyclical bending with a sinusoidal applied load, registration of bending deformations and the analyze of fatigue durability according to relation module of elasticity-frequency of weighting-temperature. The fastening of the sample is fulfilled by jamming along the edges, the load is applied to the center of the sample to the maximum at sequential weighting in specific regimes. Duration and amplitudes of weighting is defined according to quantity asset of a defined frequency range into the common frequency spectrum of transport vehicles' impacting on asphalt concrete pavement.
EFFECT: increases accuracy and reliability of results.
FIELD: testing engineering.
SUBSTANCE: method comprises making same specimens from the material to be tested, , applying the specimens one on the other so that they are in coincident over the periphery, and carrying out cyclic loading of the specimens up to their breaking down.
EFFECT: enhanced reliability.
FIELD: technology for determining physical and mechanical properties of materials.
SUBSTANCE: in accordance to method, characteristic of material, determining Bauschinger effect, is measured, by plastic twisting in direct and reverse directions of cylindrical samples. Conditional shifting yield point during reverse twisting of sample of solid cross-section is determined by means of calculation according to formula.
EFFECT: it is possible to determine characteristic of material, determining the Bauschinger effect, at large shift deformation degrees.
FIELD: mechanical engineering.
SUBSTANCE: proposed method that can be used in production of electronic devices, analysis of fibrous-structure refractory metals and alloy TsM2A sheets and their checking for manufacturability includes detection of round grains by means of 900-1000 microscope and evaluation of fiber microhardness loss at points of their accumulation. Prior to stamping parts blanks undergo additional annealing at user's to optimize their microstructure and to facilitate sheet manufacture.
EFFECT: enhanced yield of stampings.
1 cl, 2 dwg
FIELD: technology for researching hardness properties of parts, possible use for non-destructive control over quality of parts, primarily cast carrying parts of railroad train.
SUBSTANCE: in accordance to method, several standard parts, in most strained zone of which defects are present with maximal allowed sizes, load is introduced in stepped manner, firstly in resilient and then in resilient-plastic deformation areas while performing acoustic-emission control and measuring of densities of noise energy in zone of placement of defects and computation of their average values at each loading stage. Average value of load reached at maximal bend is determined, then durability is tested and number of cycles left till destruction is determined with trust probability α and load, exceeding durability limit of base parts. Static loading of controlled parts is performed analogically to standard parts with determining of densities of noises energy in resilient and resilient-plastic deformation areas, and also static durability, and under given conditions, fatigue parameter of usability of parts is computed.
EFFECT: increased efficiency of non-destructive control and trustworthiness when determining carrying capacity of parts during manufacturing and maintenance.
FIELD: methods for determining modulus of elasticity of material.
SUBSTANCE: method includes affecting a sample of researched material by freely falling indenter of ball-like shape with known properties and time between first and second impacts of indenter with sample are measured, while additionally measured is time of impact of indenter with sample. Calculation of modulus of elasticity is performed by means of mathematical resilient-viscous model with utilization of experimentally determined values, for that purpose system including sample of researched material and indenter is replaced at stage of their contact by mathematical resilient-viscous model. Preliminary value of rigidity coefficient of resilient element of given model is given and time between first and second impacts of model with sample are calculated, while selecting numeric value of viscosity coefficient of viscous element of mathematical resilient-viscous model, at which value of time between first and second impacts of indenter and sample coincide. At selected numeric value of viscosity coefficient of viscous element of model, time of impact of model and sample is calculated, while selecting numeric value of coefficient of rigidity of resilient material of model. Modulus of elasticity of researched material of sample is estimated on basis of numeric value of rigidity coefficient of resilient element of mathematical resilient-viscous model, at which time of impact of mathematical resilient-viscous model coincides with measured time of indenter impact.
EFFECT: increased trustworthiness, expanded area of possible use, simplification of method.
FIELD: finding areas of pre-failure of constructions of flying vehicles.
SUBSTANCE: method is based upon loading constructions with increasing load. Method includes measurement of optical signals in areas of constructions by using light guides, light-emitting diode, optical radiation receiver and measuring device. Fiber-optic light guide is rigidly attached onto the construction within areas of possible emergence of cracks by means of radiation-transparent glue. Short pulse is applied through one start point of light guide by means of light-emitting diode. After being reflected from free end of light guide, pulse returns to optical radiation receiver. Silver coating with thickness of approximately 1 mcm is applied onto the light guide. Measuring pulse is compared with pulse coming from light-emitting diode through reference light guide. Comparison is carried out in photoelectric signal processing unit. Relation of signal is also processed in photoelectric signal processing unit and result is sent to measuring device.
EFFECT: improved truth of results; higher comfort at finding areas of pre-failure.
2 cl, 1 dwg
FIELD: oil and gas industry.
SUBSTANCE: method includes taking core, making correct shape samples, stepped loading of samples with delay for pressure stabilization at each load and determining of volume of pores before and after each load. Samples are loaded cyclically. Each cycles comprises serially loading with pressure, by means of compression, in parallel and in perpendicular to bed, pressure stabilization, by determining by weighting method of pores volume, including difference of masses of water-saturated and dry sample before and after compression. Cycles are repeated until reaching resilience limit, moment of which is fixed on basis of steep increase of Poisson coefficient, calculated from mathematical formula: where ν - Poisson coefficient; ΔM, ΔM1 - differences of masses of water-saturated and dry sample before and after compression, kg; d - sample diameter, m; l - sample length, m.
EFFECT: higher precision.
FIELD: testing technologies.
SUBSTANCE: method includes using symmetric cycles with different load levels to unload standard samples until destruction, calibration dependence of number of cycles until destruction from load value is determined, after that at least one tested sample is cyclically load, with changing of cycle parameters in turns. Each loading step of tested object includes recording infrared radiation from its surface, using it to measure temperature increase in place of local heating of object and determining dependences of increases of temperature from load value and cycle asymmetry coefficient, after that calibration dependence for each increase of temperature is used to determine appropriate number of cycles until destruction.
EFFECT: higher precision and efficiency.
FIELD: investigating strength properties of solid materials.
SUBSTANCE: device comprises two vertical pillars, which are provided with a vertically movable unit for unbalancing the specimen-weight system and synchro transmitter, and two horizontal platforms. The axially aligned top and bottom clamps for the specimen are secured to the top plate. The bottom clamp is made of a vertical rod with the area for mounting the stack weight. The movable horizontal plate is mounted on the vertical pillars for permitting vertical movement and has an opening whose center is in coincidence with the longitudinal axis of the specimen and clamps. The opening receives the vertically movable unit for setting the specimen with the weight out of balance. The unit is made of an electromagnet with the core whose diameter is less than that of the opening. The movable plate is provided with a unit having roller system, which is composed of three pairs of rollers arranged at an angle of 120o to each other and embraces the bottom clam whose cross-section is a regular hexahedron. The top clamp is made of a cantilever provided with a strain-gauge transducer.
EFFECT: enhanced reliability of determining.
FIELD: testing engineering.
SUBSTANCE: bench comprises asynchronous electric motor and balancing machine interconnected through the shaft to be tested, control unit, and resonance pickup mounted on the shaft and connected with the input of the control unit. The bench is provided with the frequency converter, DAC unit, thyristor controller of voltage, and inverter. The first output of the control unit is connected with the frequency converter connected to the circuit for power supply to the asynchronous motor. The second output of the control unit is connected in series with the DAC unit and thyristor voltage controller connected with the exciting winding of the balancing machine. The circuit of the armature of the balancing machine is connected to the inverter.
EFFECT: enhanced reliability of testing.