A slow energy consumption test method and apparatus for evaluating the impact resistance of thermoplastic resins

Abstract

The application provides a slow energy consumption test method and device for evaluating impact resistance of thermoplastic resin, comprising the following steps: step S1, synchronously measuring strain, stress and temperature of a test sample in a mechanical slow loading process; step S2, post-processing a temperature drop part in the measured temperature, subtracting a temperature drop starting time from a measurement time, and subtracting a long-term temperature of the temperature drop from a measurement temperature, so as to obtain a temperature drop-time result; step S3, performing parameterized fitting to perfectly fit an initial time to an end time and the long-term temperature of the temperature drop process, so as to determine a coefficient χ; step S4, using the determined coefficient χ and a time step of real-time temperature measurement, calculating adiabatic temperature rise in a plastic deformation process; step S5, using specific heat capacity of the material at a starting temperature, calculating slow energy consumption according to a relative temperature difference between the adiabatic temperature rise and the starting temperature; and step S6, obtaining stress-strain-adiabatic temperature rise-energy consumption data, synchronously and accurately measuring stress, strain and energy consumption.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of test for evaluating the impact resistance of thermoplastic resin, and particularly relates to a slow energy dissipation test method and device for evaluating the impact resistance of thermoplastic resin. BACKGROUND

[0002] Thermoplastic resin such as polycarbonate (PC) has excellent impact resistance, and is often damaged and destroyed under large deformation in engineering applications such as aircraft canopy, full transparent mobile phone, and high pressure medical injector. Mastering the impact resistance of the material is an important part of the strength analysis of engineering structural parts and the realization of reliability design. Due to heat exchange between the measurement environment and the test sample, a rapid loading experiment is usually carried out to directly measure the dissipated heat and stress response. However, high strain rate experiment is relatively difficult to characterize, high in cost, and single in loading mode. Moreover, only part of the stress behavior of the material under complex loading conditions such as cyclic loading (slow speed) can be measured, and the characterization results of the thermal response are lacking, so as to provide comprehensive characterization data for the evaluation of the impact resistance of the material. Therefore, it is urgent to develop a method for accurately measuring the plastic dissipation energy of the impact resistance material under slow loading. SUMMARY

[0003] In view of the above technical problems, the present application provides a slow energy dissipation test method and device for evaluating the impact resistance of thermoplastic resin. The method is a measurement method for the dissipated energy and representative stress-strain of thermoplastic polymer in the slow plastic deformation process. The mechanical property testing equipment, infrared thermal imager and optical strain measuring device are integrated together to accurately measure the stress, strain and energy dissipation at the same time.

[0004] Note that the description of these objects does not hinder the existence of other objects. One embodiment of the present application does not need to achieve all the above-mentioned objects. The objects other than the above-mentioned objects can be extracted from the description, drawings and claims.

[0005] The present application achieves the above technical objects by the following technical means.

[0006] A slow energy dissipation test method for evaluating the impact resistance of thermoplastic resin, comprising the following steps:

[0007] Step S1, synchronously measuring the strain, stress and temperature of the test sample in the mechanical slow loading process; the temperature is measured by the infrared thermal imager; the strain is measured by the optical strain measuring device; and the stress is measured by the torque of the mechanical property testing equipment, and calculated according to formula one.

[0008]

[0009] Wherein, τ is stress; M is actual measured torque, d is the average of the inner and outer diameter of the thin wall of the test sample, δ is the thickness of the thin wall of the test sample;

[0010] Step S2, post-processing the temperature drop part in the temperature measured in step S1, subtracting the temperature drop starting time t1 from the measurement time, and subtracting the long-term temperature T of the temperature drop from the measurement temperature ∞ , so as to obtain the temperature drop-time result;

[0011] Step S3, according to the temperature drop-time result obtained in step S2, parameterized fitting is carried out by using formula two, so as to determine the initial time t1 to the end time t2 and the long-term temperature T of the temperature drop process ∞ , and the fitting is good, so as to determine the coefficient χ in formula two:

[0012]

[0013] Wherein, T is the actual measured temperature, T A is the starting temperature of the temperature drop, χ is the equivalent coefficient of the convection model, and t is the actual measurement time;

[0014] Step S4, according to the entire real-time measured temperature, using the coefficient χ determined in step S3 and the time step Δt of real-time temperature measurement, the adiabatic temperature rise in the plastic deformation process is calculated by using summation equation three, that is, the adiabatic temperature:

[0015]

[0016] Wherein, T 绝热 is the adiabatic temperature, T t0 is the temperature at time t0, that is, the actual measured starting temperature, T is the actual measurement time, T ti is the temperature at time t i , t i is the temperature at time t p , and t t represents each measurement time i.

[0017] Step S5, using the specific heat capacity c p of the material at the starting temperature, according to the relative temperature difference of the adiabatic temperature rise obtained in step S4 and the starting temperature, the slow energy consumption Δξ t is calculated by using formula four:

[0018]

[0019] Step S6, obtaining the stress-strain-adiabatic temperature rise-energy consumption data, completing the thermodynamic measurement.

[0020] In the scheme, the material of the test sample is polycarbonate (PC), the test sample is a circular ring, the wall thickness is 1 mm, the width is 2 mm, the small round corners on both sides are R1 mm, the thin wall inner diameter is 18 mm, the outer diameter of the end flange is 30 mm, the sample thickness of the whole test sample is 12 mm, and the machining error of all dimensions is ±0.1 mm.

[0021] In the scheme, the strain rate of slow loading is 0.001-0.1 s -1 .

[0022] In the scheme, the duration between the initial time t1 and the end time t2 of the temperature drop is 8-12 seconds.

[0023] In the scheme, the long-term temperature T ∞ of the temperature drop is 300-400 seconds apart from the initial time t1 of the temperature drop.

[0024] A device for implementing the slow energy consumption test method for evaluating the impact resistance of the thermoplastic resin, comprising an infrared thermal imager, a mechanical property testing device, an optical strain measuring device, and a control system, the infrared thermal imager, the mechanical property testing device, and the optical strain measuring device are connected with the control system respectively;

[0025] The mechanical property testing device clamps the test sample, and the infrared thermal imager and the optical strain measuring device are placed on both sides or the same side of the test sample;

[0026] The infrared thermal imager is used to measure the temperature of the test sample during mechanical slow loading; the optical strain measuring device is used to measure the strain of the test sample during mechanical slow loading; and the mechanical property testing device is used to measure the torque of the test sample during mechanical slow loading.

[0027] In the scheme, the mechanical property testing device comprises a rotating shaft, a clamp, and a torque sensor;

[0028] The clamp clamps the test sample in the middle, one side of the clamp is connected with the rotating shaft, and the other side is provided with a torque sensor, and the torque sensor is connected with the control system; the rotation of the rotating shaft drives one side of the clamp and the test sample to twist, thereby causing strain, and the torque sensor is used to detect the applied torque of the test sample and transmit it to the control system.

[0029] In the scheme, the test sample is a thin-walled circular ring, and the flanges at both ends of the test sample are bonded with the clamp.

[0030] In the scheme, the optical strain measuring device comprises two CCD cameras and a light source, and the CCD cameras are connected with the control system; the CCD cameras are used to take pictures of the torsional strain of the test sample.

[0031] In the above scheme, the infrared thermal imager, the mechanical property testing equipment and the optical strain measuring device are connected with the control system through a synchronous trigger.

[0032] Principle of the application:

[0033] In the slow deformation process of the thermoplastic resin, the heat exchange (convection and heat conduction) between the test sample and the surrounding environment will gradually cool the temperature rise caused by plastic dissipation energy, and the equivalent heat loss can be quantitatively described by using a simple heat convection formula, and the equation is The integral of the equation is

[0034]

[0035] Wherein

[0036] ρ is the mass density of the test sample, w is the width of the test sample, and h is the heat convection coefficient.

[0037] After the mechanical loading, the material has no plastic energy dissipation, and only heat exchange exists, so that the temperature drop in the current stage can be used to determine the coefficient χ in the heat convection equation.

[0038] By integral operation, formula two is obtained, and parameter fitting is carried out to determine the initial time t1 to the end time t2 and the long-term temperature T ∞ The fitting is good, so as to determine the coefficient χ in formula two:

[0039]

[0040] The early stage data of the temperature drop can obtain the optimal heat convection equation coefficient, and the principle is that compared with heat conduction, heat convection transfers heat faster, and the early stage of temperature drop is mainly dominated by heat convection, and the later stage is a mixed mode of heat convection and heat conduction.

[0041] In addition, the thermal conductivity of the resin is poor, and the loss of plastic dissipation energy caused by heat conduction accounts for a relatively small proportion; finally, according to the real-time temperature measurement in the loading process, combined with the heat convection equation determined above, the adiabatic temperature rise in the plastic deformation process is calculated according to the formula The summation integral equation is converted into summation formula

[0042]

[0043] Finally, according to the relative temperature difference between the adiabatic temperature rise and the initial temperature, the plastic dissipation energy is calculated by using the formula

[0044] Compared with the prior art, the beneficial effects of the present application are: ​

[0045] 1. The application can make up the single loading mode of high-speed impact performance test, reduce the test cost, and expand the test method of material impact resistance performance evaluation;

[0046] 2. The application can determine the key coefficient of the heat convection equation by using the temperature drop after the end of external load, and can quantitatively characterize the energy dissipation of the slow deformation process of the sample;

[0047] 3. The application can obtain ideal key coefficients by using early temperature drop data in the temperature drop process, thereby improving the accuracy of material slow energy dissipation test;

[0048] 4. The application can realize the synchronous measurement of plastic dissipation energy (or adiabatic temperature rise) and stress-strain of thermoplastic polymer, thereby mastering the thermodynamic mechanism of thermoplastic resin, providing characterization data for the evaluation of impact resistance of such materials, and accurately evaluating the dynamic impact response of actual engineering structure, i.e. impact energy absorption and dissipation.

[0049] Note that the description of these effects does not hinder the existence of other effects. One embodiment of the application does not necessarily have all the above effects. Effects other than the above can be clearly seen and extracted from the description, drawings, claims, etc. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a structural schematic diagram of a slow energy dissipation test device for evaluating the impact resistance of a thermoplastic resin according to an embodiment of the application;

[0051] Figure 2 is a measurement schematic diagram of strain according to an embodiment of the application;

[0052] Figure 3 is a measurement schematic diagram of stress according to an embodiment of the application;

[0053] Figure 4 is a measurement schematic diagram of temperature according to an embodiment of the application;

[0054] Figure 5 is a post-processing schematic diagram of temperature drop curve according to an embodiment of the application;

[0055] Figure 6 is a schematic diagram of determining the heat convection model coefficient by using the parameterization fitting method according to an embodiment of the application;

[0056] Figure 7 is a schematic diagram of calculating the adiabatic temperature rise by using the heat convection model according to the actual temperature measurement according to an embodiment of the application;

[0057] Figure 8is a schematic diagram of determining plastic dissipation energy according to adiabatic temperature rise in an embodiment of the present application;

[0058] Figure 9 is a measurement of real-time stress-strain-temperature under unidirectional torsion in Example 1 of the present application, wherein Figure 9 (a) is a torsional shear stress curve under unidirectional torsion, Figure 9 (b) is a shear strain curve under unidirectional torsion, Figure 9 (c) is a temperature curve under unidirectional torsion, Figure 9 (d) is a temperature difference curve under unidirectional torsion;

[0059] Figure 10 is a characterization result of adiabatic temperature rise and plastic dissipation energy under unidirectional torsion in Example 1 of the present application, wherein Figure 10 (a) is an adiabatic temperature rise curve under unidirectional torsion, Figure 10 (b) is a plastic dissipation energy curve under unidirectional torsion.

[0060] Figure 11 is a measurement of real-time stress-strain-temperature under reverse cyclic torsion in Example 2 of the present application, wherein Figure 11 (a) is a torsional shear stress curve under reverse cyclic torsion, Figure 11 (b) is a shear strain curve under reverse cyclic torsion, Figure 11 (c) is a temperature curve under reverse cyclic torsion, Figure 11 (d) is a temperature difference curve under reverse cyclic torsion;

[0061] Figure 12 is a characterization result of adiabatic temperature rise and plastic dissipation energy under reverse cyclic torsion in Example 2 of the present application, wherein Figure 12 (a) is an adiabatic temperature rise curve under reverse cyclic torsion, Figure 12 (b) is a plastic dissipation energy curve under reverse cyclic torsion.

[0062] In the figure, 1 is an infrared thermal imager, 2 is a test sample, 3 is a mechanical property testing device, 31 is a rotating shaft, 32 is a clamp, 33 is a torque sensor, 4 is an optical strain measurement device, 41 is a light source, 5 is a control system, 51 is a synchronous trigger, 6 is a strain-time measurement curve, 7 is a stress-time measurement curve, 8 is a real-time temperature-time measurement curve, 81 is a temperature drop curve, 82 is a t1 to t2 and long-term temperature curve, 83 is an adiabatic temperature rise curve, and 84 is a plastic dissipation energy curve. DETAILED DESCRIPTION

[0063] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and are not to be understood as limiting the present application.

[0064] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "front", "back", "left", "right", "up", "down", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0065] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0066] In order to describe the implementation details of the present application in detail, the slow energy consumption test method for evaluating the impact resistance of thermoplastic resin of the present application is described below in conjunction with the drawings.

[0067] A device for implementing the slow energy consumption test method for evaluating the impact resistance of thermoplastic resin, comprising an infrared thermal imager 1, a mechanical property testing device 3, an optical strain measuring device 4 and a control system 5, the infrared thermal imager 1, the mechanical property testing device 3, the optical strain measuring device 4 are connected with the control system 5 respectively;

[0068] The mechanical property testing device 3 clamps the test sample 2, and the infrared thermal imager 1 and the optical strain measuring device 4 are placed on both sides or the same side of the test sample 2;

[0069] The infrared thermal imager 1 is used to measure the temperature of the test sample 2 in the mechanical slow loading process; the optical strain measuring device 4 is used to measure the strain of the test sample 2 in the mechanical slow loading process; and the mechanical property testing equipment 3 is used to measure the torque of the test sample 2 in the mechanical slow loading process.

[0070] The mechanical property testing equipment 3 comprises a rotating shaft 31, a clamp 32 and a torque sensor 33; the clamp 32 clamps the test sample 2 in the middle, one side of the clamp is connected with the rotating shaft 31, and the other side is provided with the torque sensor 33; the torque sensor 33 is connected with the control system 5; the rotation of the rotating shaft 31 drives one side of the clamp to twist the test sample 2, so that the strain occurs; and the torque sensor 33 is used to detect the applied torque of the test sample 2 and transmit it to the control system 5.

[0071] The test sample 2 is a thin-walled ring, and the flanges at both ends of the test sample 2 are bonded with the clamp 32 through high-strength glue.

[0072] The optical strain measuring device 4 comprises two CCD cameras and a light source 41, and the CCD cameras are connected with the control system 5; the CCD cameras are used to shoot the torsional strain pictures of the test sample 2.

[0073] The infrared thermal imager 1, the mechanical property testing equipment 3 and the optical strain measuring device 4 are connected with the control system 5 through a synchronous trigger 51.

[0074] A slow energy consumption test method for evaluating the impact resistance of thermoplastic resin, comprising the following steps:

[0075] Step S1, synchronously measuring the strain, stress and temperature of the test sample 2 in the mechanical slow loading process; the temperature is measured by the infrared thermal imager 1; the strain is measured by the optical strain measuring device 4; and the stress is measured by the torque of the mechanical property testing equipment 3, and is calculated according to Formula I;

[0076]

[0077] Wherein, τ is the stress; M is the actually measured torque, d is the average value of the inner and outer diameters of the thin wall of the test sample 2, and δ is the thickness of the thin wall of the test sample 2;

[0078] Step S2, post-processing the temperature drop part in the temperature measured in step S1, subtracting the temperature drop starting time t1 from the measurement time, and subtracting the long-term temperature T of the temperature drop from the measurement temperature ∞ , to obtain the temperature drop-time result;

[0079] Step S3, according to the temperature drop-time result obtained in step S2, parameterizing fitting is performed by using Formula II to obtain the initial time t1 to the end time t2 and the long-term temperature T of the temperature drop process ∞The fit is perfect, thus determining the coefficient χ in Equation 2:

[0080]

[0081] Where T is the actual measured temperature, T A χ is the initial temperature of the temperature drop, χ is the equivalent coefficient of the convection model, and t is the actual measurement time;

[0082] Step S4: Based on the total real-time measured temperature, using the coefficient χ determined in step S3 and the time step Δt of the real-time temperature measurement, calculate the adiabatic temperature rise during the plastic deformation process, i.e., the adiabatic temperature, using the summation equation three:

[0083]

[0084] Among them, T 绝热 T is the adiabatic temperature. t0 Let be the temperature at time t0, i.e., the actual measured starting temperature, and T be the actual measurement time. For time t i Temperature at time t i To represent each measurement time i;

[0085] Step S5, utilizing the specific heat capacity c of the material at the initial temperature. p Based on the relative temperature difference between the adiabatic temperature rise and the initial temperature obtained in step S4, the slow energy consumption Δξ is calculated using Equation 4. t :

[0086]

[0087] Step S6: Obtain data on stress-strain-adiabatic temperature rise-energy consumption to complete the thermodynamic measurement.

[0088] In one specific embodiment of the present invention, the test sample 2 is made of polycarbonate (PC), is a ring with a wall thickness of 1 mm, a width of 2 mm, a small fillet radius (R) of 1 mm on both sides, a thin-walled inner diameter of 18 mm, an outer diameter of the end flange of 30 mm, a sample thickness of 12 mm for the entire test sample 2, and a machining error of ±0.1 mm for all dimensions.

[0089] The strain rate of the slow loading is 0.001-0.1 s⁻¹. -1 .

[0090] The duration between the initial time t1 and the end time t2 of the temperature drop is 8-12 seconds, which can obtain the optimal equivalent coefficient χ.

[0091] The long-term temperature T of the temperature drop ∞The time difference between the current time t3 and the initial temperature drop time t1 is 300-400 seconds, which is used to obtain the optimal long-term temperature T. ∞ .

[0092] Implementation Example 1:

[0093] In this embodiment, the test sample is polycarbonate (PC), and the specific heat capacity of test sample 2 is 1.2 J / gK; Figure 9 As shown, the loading method was unidirectional torsion, and stress test curve 90, shear strain test curve 91, and real-time temperature test curve 92 were measured simultaneously; the design strain rate was 0.01 s². -1 The actual measured strain rate was 0.006 s⁻¹. -1 The maximum loading strain is approximately 70%; after loading, an unloading phase is applied, unloading to 60% of the yield stress, i.e., the time difference between t1 and t2 is 12 seconds; the time difference between the long-term temperature drop and the initial temperature drop is 350 seconds; the equivalent coefficient χ is determined using temperature drop data test curve 93. If the entire temperature drop curve is used, coefficient 94 is obtained: χ = 0.023; only the early temperature drop t1 to t2 and the long-term temperature T are used. ∞ =19.22℃ will yield the optimal coefficient 95: χ=0.03; Figure 10 The figures show the adiabatic temperature rise and plastic energy consumption during the unidirectional slow torsion process. As can be seen from the figures, during the slow loading to 70% strain, compared with the real-time temperature measurement curve 98, the adiabatic temperature rise curve 96 obtained using the optimal coefficient χ = ​​0.03 is higher than the adiabatic temperature rise curve 97 obtained using the conventional method χ = 0.023. Correspondingly, from the obtained plastic energy consumption curve 99 and the plastic energy consumption curve 100 obtained using the conventional method, it can be seen that the obtained plastic energy consumption of 9.2 J / g is more accurate than the plastic energy consumption of 7.4 J / g obtained using the conventional method.

[0094] Implementation Example 2:

[0095] In this embodiment, the test sample is polycarbonate (PC), such as Figure 11 As shown, the loading method was forward-reverse cyclic torsion, and stress test curve 110, shear strain test curve 111, and real-time temperature test curve 112 were measured simultaneously; the design strain rate was 0.1 s². -1 The actual measured strain rate was 0.01 s⁻¹. -1; the strain range of the cyclic loading is -51% to 43%; the number of loading cycles is 3.25; the sample is kept static after the loading, the time difference between t1 and t2 is 8 seconds; the long-term temperature of the temperature drop is 300 seconds; the equivalent coefficient χ is determined by using the temperature drop data curve 115, if the entire temperature drop curve is used, the coefficient 113: χ = 0.041 will be obtained; only the early temperature drop t1 to t2 and the long-term temperature T ∞ = 19.6℃ will obtain the optimal coefficient 114: χ = 0.055; from Figure 12 It can be seen from the above that, compared with the real-time temperature measurement curve 118, the adiabatic temperature rise curve 116 obtained by using the optimal coefficient χ = 0.055 is higher than the adiabatic temperature rise curve 117 obtained by using the conventional method χ = 0.041, and correspondingly, the accurate plastic energy dissipation obtained from the plastic energy dissipation curve 119 and the plastic energy dissipation curve 120 obtained by using the conventional method is 49.4 J / g, while the plastic energy dissipation obtained by using the conventional method is only 37.4 J / g.

[0096] The present application uses the temperature drop after the loading to calibrate the coefficient of the simple heat convection formula, so as to quantitatively characterize the loss of plastic heat dissipation caused by heat exchange during the loading process; based on the heat convection formula and combined with the entire real-time temperature measurement, the adiabatic temperature rise and the plastic energy dissipation of the resin during the slow deformation process are calculated, and finally the slow energy dissipation of the test sample and the related thermodynamic behavior, i.e. the stress-strain-adiabatic temperature rise-energy dissipation data are obtained. The present application can reduce the testing cost of the characterization data required by the thermodynamic research of the impact-resistant polymer material, break through the single loading mode in the high-speed thermodynamic test, and help to comprehensively evaluate the impact resistance of the actual engineering structure material. The present application can be used for synchronous measurement of the stress-strain-adiabatic temperature rise of the test sample.

[0097] It should be understood that, although the present specification is described in terms of various embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be combined to form other embodiments which can be understood by those skilled in the art.

[0098] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present application, and they are not used to limit the protection scope of the present application, and any equivalent embodiments or changes made without departing from the spirit of the present application should be included in the protection scope of the present application.

Claims

1. A slow energy consumption test method for impact resistance evaluation of thermoplastic resins, characterized by, The method comprises the following steps: Step S1, synchronously measuring the strain, stress and temperature of the test sample (2) in the mechanical slow loading process; the temperature is measured by the infrared thermal imager (1); the strain is measured by the optical strain measuring device (4); the stress is measured by the mechanical property testing equipment (3) to measure the torque, and the stress is calculated according to formula one; Wherein, τ is the stress; M is the actually measured torque, d is the average value of the inner and outer diameters of the thin wall of the test sample (2), and δ is the thickness of the thin wall of the test sample (2); Step S2, post-processing of the temperature drop part in the temperature measured in step S1, subtracting the temperature drop start time t1 from the measurement time, subtracting the long-term temperature T of the temperature drop from the measured temperature ∞ and thereby obtaining the temperature drop-time result; Step S3, according to the temperature drop-time results obtained in step S2, the parameter fitting is carried out by using formula two, so as to determine the initial time t1 to the end time t2 and the long-term temperature T of the temperature drop process ∞ The fitting is good, so as to determine the coefficient χ in formula two: where T is the actual measured temperature, T A is the initial temperature of the temperature drop, χ is the equivalent coefficient of the convection model, and t is the actual measured time. Step S4, according to the entire real-time measured temperature, using the coefficient χ determined in step S3 and the real-time temperature measurement time step Δt, the adiabatic temperature rise in the plastic deformation process is calculated by using summation equation three, that is, the adiabatic temperature: wherein T 绝热 is the adiabatic temperature, is the temperature at the time t0, i.e. the starting temperature actually measured, T is the actual measurement time, is the temperature at the time t i i, t i denotes each measurement time i; Step S5, the specific heat capacity c of the material at the initial temperature is used p The relative temperature difference between the adiabatic temperature rise obtained according to step S4 and the initial temperature is used to calculate the slow energy consumption Δξ using Equation Four t : Step S6, obtaining the stress-strain-adiabatic temperature rise-energy dissipation data, and completing the thermodynamic measurement.

2. A slow energy consumption test method for assessing the impact resistance of thermoplastic resins according to claim 1, characterized in that, The material of the test sample (2) is polycarbonate (PC), the test sample (2) is a circular ring, the wall thickness is 1mm, the width is 2mm, the small round corners on both sides are R1mm, the thin wall inner diameter is 18mm, the outer diameter of the end flange is 30mm, the sample thickness of the entire test sample (2) is 12mm, and the machining error of all dimensions is ±0.1mm.

3. A slow energy dissipation test method for impact resistance evaluation of thermoplastic resins according to claim 1, characterized in that, The slow loading strain rate is 0.001-0.1 s -1 .

4. The slow energy dissipation test method for assessing impact resistance of thermoplastic resins according to claim 1, wherein The time length between the initial time t1 and the end time t2 of the temperature drop is 8-12 seconds.

5. The slow energy dissipation test method for impact resistance evaluation of thermoplastic resins according to claim 1, wherein The long-term temperature T of the temperature drop ∞ The difference between the time t3 and the initial time t1 of the temperature drop is 300-400 seconds.

6. An apparatus for performing the slow energy dissipation test method for assessing the impact resistance of thermoplastic resins according to any one of claims 1-5, characterized in that, The infrared thermal imager (1), the mechanical property testing equipment (3), the optical strain measuring device (4) and the control system (5) are connected with each other. The infrared thermal imager (1) and the optical strain measuring device (4) are placed on both sides or the same side of the test sample (2). The infrared thermal imager (1) is used to measure the temperature of the test sample (2) in the mechanical slow loading process; the optical strain measuring device (4) is used to measure the strain of the test sample (2) in the mechanical slow loading process; and the mechanical property testing equipment (3) is used to measure the torque of the test sample (2) in the mechanical slow loading process.

7. The apparatus for slow energy dissipation testing method for impact property evaluation of thermoplastic resins according to claim 6, characterized in that, The mechanical property testing equipment (3) comprises a rotating shaft (31), a clamp (32) and a torque sensor (33). The middle of the clamp (32) clamps the test sample (2), one side of the clamp is connected with the rotating shaft (31), and the other side is provided with the torque sensor (33), the torque sensor (33) is connected with the control system (5); the rotation of the rotating shaft (31) drives one side of the clamp to drive the test sample (2) to twist, so that the strain occurs, and the torque sensor (33) is used to detect the applied torque of the test sample (2) and transmit it to the control system (5).

8. The apparatus for slow energy consumption testing method for impact property evaluation of thermoplastic resins according to claim 6, characterized in that, The test sample (2) is a thin-walled circular ring, and the flanges at both ends of the test sample (2) are bonded with the clamp (32).

9. The apparatus for slow energy dissipation testing method for impact property evaluation of thermoplastic resins according to claim 6, characterized in that, The optical strain measuring device (4) comprises two CCD cameras and a light source (41), and the CCD cameras are connected with the control system (5); the CCD cameras are used to shoot the torsional strain pictures of the test sample (2).

10. The apparatus for slow energy consumption testing method for impact property evaluation of thermoplastic resins according to claim 6, wherein The infrared thermal imager (1), the mechanical property testing equipment (3), and the optical strain measuring device (4) are connected with the control system (5) through a synchronous trigger (51).

Images