75 results about "Load cycle" patented technology

The invention relates to the technical field of spring measurement, and discloses a spring fatigue life test system and a dynamic balance evaluation method, and the system comprises a reference length acquisition module, a dynamic balance state determination module, a working condition spectrum loading module, a stress-strain response data acquisition module, a damage feature extraction module and a life evaluation module. Acquiring a reference length in a free state; step increasing preload is applied, and when it is detected that the deformation rate of the to-be-detected spring is smaller than a set threshold value, it is judged that the to-be-detected spring reaches a dynamic balance state; in a dynamic balance state, loading the to-be-tested spring based on the variable amplitude load time sequence signal, and synchronously acquiring stress-strain response data; identifying the stress characteristics of the to-be-tested spring in the load period; generating a life evaluation report based on the stress characteristics; the accuracy of the fatigue life of the spring can be improved.

The invention discloses a roadbed settlement prediction method and system under an intermittent load effect. The method comprises the following steps: constructing a state evolution model of a roadbed under the action of intermittent load; cyclic stress parameters of the roadbed in the preset load period are determined, wherein the cyclic stress parameters comprise the dynamic stress amplitude, the number of cycles of the load and the initial stress value; a softening index corresponding to the roadbed is determined based on the cyclic stress parameter, a relational expression between the softening index and the load vibration frequency is established, and a modulus softening prediction model of the roadbed is determined based on the relational expression; and coupling the modulus softening prediction model with the state evolution model, and determining a roadbed cumulative strain prediction model based on a coupling result, so as to determine the settlement evolution state of the roadbed under the intermittent load based on the roadbed cumulative strain prediction model. According to the invention, the finally obtained roadbed accumulated strain prediction model can reflect the actual settlement state of the roadbed under the intermittent load more truly.

The invention discloses a safety valve service life evaluation method based on pressure history statistics and dynamic damage accumulation. According to the method, only safety valve inlet pressure time sequence data is needed, a load cycle is extracted through an improved rain flow counting method, and the nonlinear damage increment is calculated according to an S-N curve model dynamically degraded along with the accumulated damage degree. According to the method, a self-adaptive failure probability threshold is established based on historical failure data, and probabilistic prediction of the residual life is realized. The model is clear in physical significance, only needs a single data source, significantly reduces the implementation complexity and cost, greatly improves the precision of life prediction by considering the degradation of material performance, and is especially suitable for predicting the accelerated failure risk of the safety valve in the later period of long-term service.

The invention relates to the technical field of geotechnical engineering anchoring, in particular to a method for testing the degradation characteristic of the bearing performance of a recyclable anchor rod under cyclic loading. The method comprises the following steps: preparing a unit body sample anchor-rock interface unit body sample, simulating weathered soft rock according to a specific ratio, pouring a self-compacting concrete anchoring body, and curing and forming; setting a combined parameter of a reference load ratio and a load cycle index, applying a triangular wave cyclic load to simulate a traffic condition, and executing a pull-out test to collect load-displacement data; constructing a two-parameter coupled shear strength degradation model based on test data, and proposing a shear stress-displacement curve model; an anchor rod load transfer control equation is established in combination with the Poisson effect, and shear stress distribution of the anchoring section is iteratively solved by adopting a discrete recursion method; the model is verified through a foundation pit engineering case, the ultimate bearing capacity degradation law of the anchor rod under long-term cyclic loading is predicted, and it is proved that the model can guide engineering safety design. According to the method, the coupling characterization of the cyclic load parameter and the interface degradation mechanism is realized.

The invention discloses a mining wheel ventilation area optimal value determination method and an overall strength evaluation method thereof. The mine car wheel lacks a processing method and a quantitative standard for correspondingly and accurately evaluating the overall structural strength of the wheel in different use stages; the method for determining the optimal value of the ventilation area of the mining wheel comprises the following steps of: establishing an initial mining wheel model according to standard bending moment data and standard radial load data; the method comprises the following steps of: performing stress field analysis and fatigue life evaluation on radial and bending working conditions of an initial mining wheel model by combining a finite element model and a method for evaluating the fatigue life of the wheel to obtain actual stress states and maximum load cycle index values of the wheel under different working conditions; and obtaining the optimal value of the wheel ventilation area through topological optimization according to the actual stress states of the wheel under different working conditions and the maximum number of cycles of the load.

The invention discloses a ball screw accumulated fatigue damage value calculation method based on a dynamic threshold LLC method, and is applied to the technical field of ball screw pair bearing life research. Comprising the following steps: simplifying a load spectrum of a ball screw based on a dynamic threshold Level-Crossing Counting method; extracting a complete load cycle from the simplified load spectrum by using a rain flow counting method; correcting the stress cycle of the ball screw in combination with a Goodman model; and calculating an accumulated fatigue damage value caused by the corrected stress cycle on the basis of a Palmron-Miner linear accumulated damage theory. According to the method, the calculation accuracy of the accumulated fatigue damage value in the fatigue failure process of the ball screw pair is improved, and the design and performance improvement of the ball screw pair can be better guided.

The invention provides an aero-engine cold end disc life test evaluation spectrum compilation method and system, and the method comprises the steps: obtaining an actual measurement flight profile of a target engine, carrying out the rain flow counting and filtering preprocessing, and extracting a load cycle average amplitude pair; dividing a secondary cycle into multi-stage loads based on clustering analysis, and reducing the dimension of a two-dimensional load spectrum into a one-dimensional load spectrum through equivalent conversion; and determining the load frequency of each stage by combining an equal damage principle and an equal area method, and finally generating a test evaluation spectrum containing a main cycle and a secondary cycle. According to the method, through primary and secondary cycle separation, load grade clustering and low-high-low loading sequence design, distribution characteristics and sequence effects of actual loads are fully simulated, the problem that secondary cycle influences are ignored in an existing method is solved, the precision of a cold end disc service life test is remarkably improved, and a reliable basis is provided for determining and prolonging the service life of an aero-engine.

The present disclosure describes embodiments of a permanent deformation model for soils and granular materials with the application of the Shift Factor (SF) concept. The model was structured following the guidelines provided by the standard DNIT 179, but with the modification of the number of loading cycles and the stress pairs to be applied. Instead of 150,000, 10,000 load cycles were used for each stress pair, with the exception of the most severe pair, for which 150,000 load cycles continued to be applied. From the results obtained for each stress pair, there is constructed a master curve representative of one of the test stress pairs, selected as a reference. Embodiments of the present disclosure finds its field of application in the characterization of the permanent deformation of soils and granular materials.

The invention discloses an aero-engine double-characteristic program spectrum compilation method, and relates to the technical field of aero-engine structural part load spectrum compilation, and the aero-engine double-characteristic program spectrum compilation method comprises the steps: obtaining and preprocessing an aero-engine load time history, and obtaining an aero-engine load cycle; performing clustering analysis to obtain a typical characteristic cycle, and constructing a typical characteristic load program spectrum block; establishing a multi-objective optimization model, solving by using a particle swarm to obtain an optimal load grade frequency, and determining the number of program spectrum block loads of each grade of typical characteristic circulation; and determining the sequence of program spectrum blocks according to the position of a typical characteristic load hysteresis loop. According to the method, blindness of a traditional equal-interval or fixed-proportion division method is effectively overcome, scientificity and representativeness of load grading are remarkably improved, program spectrum compiling work is remarkably simplified, and standardization, repeatability and engineering implementation efficiency of the program spectrum compiling method are improved.

The invention discloses a method for predicting fatigue life of a high-temperature alloy electron beam welding joint by considering residual stress, which comprises the following steps of: on the basis of a traditional S-N curve of the welding joint, superposing the residual stress, and considering that the residual stress is released along with a fatigue load cycle number so as to correct the S-N curve. Firstly, a change curve of the residual stress attenuation rate Sr along with the cycle index in the fatigue loading process of the high-temperature alloy electron beam welding head is established, and a residual stress reduction coefficient K is obtained through calculation based on the Sr curve. The initial residual stress is corrected by introducing a reduction coefficient K, and the initial residual stress and external load stress are linearly superposed to establish a damage parameter, so that a welded joint fatigue life prediction model considering residual stress release is established. The model has relatively high life prediction precision, and compared with the mode that residual stress is not considered, the life prediction dispersion zone is improved from + / -3 times to + / -1.25 times.

A system may include a power component, the power component including at least one device processor configured to: obtain load data, wherein the load data comprises a power characteristic associated with at least one of a high-load element or a low-load element, obtain a trained power management artificial intelligence (AI) and / or machine learning (ML) model, based at least on the load data and the trained power management Al and / or ML model, infer a direct current (DC) link voltage adjustment, wherein the DC link voltage adjustment is correlated with a predicted load cycle parameter; and cause the power component to alter a DC link voltage from an initial level to an adjusted level based on the DC link voltage adjustment.

The present application relates to the technical field of high-temperature structural component fatigue strength design and life assessment, and particularly relates to a low-cycle multi-axial fatigue life prediction method based on powder high-temperature alloy damage mechanism. The method comprises: for the dangerous point of the component under non-isothermal multi-axial cyclic loading, calculating pure fatigue damage, pure creep damage and fatigue-creep interaction damage caused by a single load cycle; accumulating the pure fatigue damage, the pure creep damage and the fatigue-creep interaction damage to obtain the total damage of the single load cycle; taking the inverse of the total damage to predict the total failure life of the component under non-isothermal multi-axial cyclic loading. The method of the present application realizes effective prediction of the low-cycle multi-axial fatigue life of the powder high-temperature alloy component by accurately decomposing the damage of the dangerous point under non-isothermal multi-axial cyclic loading, can more truly reflect the comprehensive prediction model of the failure physics of the powder high-temperature alloy under multi-axial thermal mechanical loading, and improves the accuracy and reliability of the life assessment.

The invention discloses an anti-loosening mechanism for connecting an output shaft of a driver with a load end and a robot, and belongs to the technical field of robots, the anti-loosening mechanism comprises a first fastener and a second fastener; the first fastener is used for fixedly connecting the second fastener with the output shaft; the second fastener is fixedly connected with the load end; an anti-skid piece is arranged between the first fastening piece and the second fastening piece and used for preventing relative rotation movement between the first fastening piece and the second fastening piece. According to the anti-loosening mechanism for connecting the output shaft of the driver with the load end and the robot, the problems that in the prior art, the output shaft of the driver is fixed only through a flange plate and a screw, the screw is prone to loosening under the environments of high-frequency positive and negative rotation alternate operation of the driver, periodic impact of the load and the like can be effectively solved; and power transmission interruption is caused.

This application relates to a device fault prediction method and device based on a digital twin model. The method includes: when the device monitoring twin model fails to detect a device fault, first obtain the operating status, temperature, and load cycle data of the device. Substitute the operating status data into the fixed fault and usage fault calculation models to obtain the corresponding fixed fault data and usage fault data. Subsequently, correct the fixed fault data according to the temperature data to obtain the temperature-corrected fixed fault data; correct the usage fault data according to the load cycle data to obtain the load-corrected usage fault data. Then, combine the temperature-corrected fixed fault data and the load-corrected usage fault data to calculate the failure data of the device on the usage time axis, and further obtain the failure curve of the device. Finally, extract the data points that meet the preset failure conditions from the failure curve as the device fault prediction information, which can effectively improve the real-time performance and accuracy in the prediction of device faults.

The invention relates to equipment for evaluating the bearing capacity of a pipeline through a wheel pressure method load test. The equipment comprises a datum beam, a counter-force frame and a plurality of wheel set pairs, the wheel set pair comprises two wheel sets which are symmetrically arranged relative to the axis of the reaction frame; the wheel set pair is mounted on the outer side of the counter-force frame through pressurizing equipment; the reference beam is provided with an independent support; and a plurality of displacement monitoring sensors are arranged between the inner wall of the test pipeline and the datum line beam. According to the equipment for evaluating the bearing capacity of the pipeline through the wheel pressure method load test, different mechanical properties of the pipe wall can be tested through asynchronous loads of a plurality of wheel sets, and the internal and external pressure bearing capacity resistance of the pipeline can be better reflected. The equipment has the characteristics of wheel sets, can be loaded and can move quickly, and a quicker method is provided for tests. Advance measurement can be carried out under a fixed pressure load condition; and after a plurality of load cycles, a certain step length can be carried out for measurement.

The invention relates to the technical field of structural design optimization, in particular to a structural parameter optimization design method and system based on sheet metal parts. The method comprises the following steps of calculating a normal included angle field by extracting a surface patch normal and a surface center coordinate of a CAD model, identifying a rib position transition area, and performing arc length calculation, curvature point analysis, step jump judgment and transition curve fitting based on a rib rotation angle coefficient. And the fatigue performance and the structural design optimization effect of the fitted curve are verified through a load cycle test. According to the method, the transition rib position area of the sheet metal part is accurately recognized through the normal included angle field, fine parameterization of the curve form is achieved in combination with the rib rotation angle coefficient, then step jump analysis and fitting are carried out, the stress streamline and structure transition design is optimized, the improvement effect of the method on the fatigue performance is verified through a load cycle test, and therefore the damage risk is effectively reduced, and the fatigue performance of the sheet metal part is improved. And the service life and reliability of the sheet metal part under the repeated load are improved.

Various embodiments of the teachings herein include a method for ascertaining at least one average capacity loss of a battery storage device. The method may include: measuring at least two load cycles of the battery storage device using a high precision coulometry apparatus; determining a first charge displacement and a second charge displacement; determining a capacity loss equal to the difference between the first charge displacement and the second charge displacement; repeatedly measuring load cycles until the capacity loss is almost constant in at least two consecutive load cycles; and ascertaining an average capacity loss based on at least two capacity losses.

The invention relates to the technical field of pressure-bearing mechanical fatigue analysis, and discloses a pressure-bearing equipment load cycle index expansion analysis method, which comprises the following steps of: firstly, acquiring cyclic load data of pressure-bearing equipment within a set time by utilizing a measurement system, and obtaining a load data fluctuation range mean value and a standard deviation; fitting a probability density function of the load cycle amplitude according to the mean value and the standard deviation; according to the probability density function, based on a composite function method, obtaining a probability function that the load fluctuation amplitude exceeds a preset fluctuation threshold value by taking any load fluctuation amplitude natural logarithm as an independent variable; and calculating the real cycle times of the loads in all different amplitude ranges according to the distribution characteristics of the probability function in the logarithmic normal form, and finally obtaining the total cycle times of the loads in all the amplitude ranges. According to the invention, the cyclic fatigue load data measured by the measuring system is analyzed and processed for the pressure-bearing equipment, so that more accurate input is provided for subsequent fatigue analysis.

The invention provides an aero-engine program block spectrum load grade determination method, system computer equipment, a storage medium and a program product, and the method comprises the steps: carrying out the rain flow counting of each flight profile of an aero-engine, obtaining the mean value and amplitude of a plurality of load cycles, and taking the mean value and amplitude as the average amplitude pair of each load cycle; taking the load history time corresponding to the maximum load in the target flight profile as a time threshold value, and determining the secondary cycle in the target flight profile as a load rising cycle or a load falling cycle; respectively carrying out clustering analysis on each load ascending cycle and each load descending cycle, and determining each clustering center by taking a load cycle average amplitude pair as an analysis variable; and taking the load grade corresponding to the average amplitude pair of each main cycle and the load grade corresponding to each clustering center as the program block spectrum load grade of the target aero-engine. The method considers the difference of the actual load spectrum, reflects the inherent attribute of the real service load, and improves the service life assessment precision of the aero-engine.

The invention discloses a fatigue health monitoring method and device for a wind turbine generator structure, equipment and a medium, and relates to the technical field of wind power monitoring, and the method comprises the steps: dynamically screening a middle extreme value based on data in an alternating load storage queue, and screening an effective extreme value; if the initial load extreme value queue is not an empty queue and the type of the effective extreme value is inconsistent with the type of a tail extreme value in the initial load extreme value queue, storing the effective extreme value in the initial load extreme value queue to obtain a load extreme value queue; when the number of extreme values in the load extreme value queue is not smaller than a preset threshold value, screening a target extreme value, if the type of the target extreme value meets a load cycle condition, constructing a first effective load cycle, and calculating an equivalent fatigue load and residual life; setting other load extreme values except the first effective load cycle as closed cycles, and calculating a second effective load cycle; the equivalent fatigue load and the residual life are calculated and corrected, the timeliness and reliability of fatigue monitoring are improved, the structural safety of the whole machine is guaranteed, and the operation and maintenance level is improved.

The invention discloses an electroplating hanger return device and method, and belongs to the technical field of electroplating automation, and the method comprises the steps: periodically collecting the displacement and speed of a hanger queue and the current data of a driving motor, calculating the no-load / full-load cycle efficiency ratio, positioning the energy consumption dispersion and the queue synchronization delay coefficient; and evaluating a comprehensive health index of the system and generating a current and time disturbance weight factor. And a speed curve smoothing factor and a current feed-forward compensation gain are dynamically adjusted based on the weight factor, adaptive closed-loop control is performed on the motor, and optimal adjustment of the return motion of the hanger is realized. According to the invention, the operation synchronism, stability and energy efficiency of the system can be improved, and the adaptability to load fluctuation and equipment aging is enhanced, so that the overall reliability and control precision of the electroplating production line are improved.

The present invention discloses a method for converting the time series loads of the mast of a rotary drilling rig of different models, and belongs to the technical field of load spectrum collection and compilation of rotary drilling rigs of engineering machinery. The method comprises the following steps: (1) extracting the time series loads of the original model under rock entry working conditions, and performing rain flow counting on the time series loads, and statistically calculating the amplitude and mean of the load cycle; (2) fitting the load amplitude with a Gaussian mixture distribution; (3) calculating the limit error value of the probability density value of the load amplitude; (4) randomly reproducing the amplitude load within the limit error; (5) reproducing the mean load according to the parameters of the converted model; (6) correcting the amplitude load according to the upper limit of the maximum value of the converted model; (7) correcting the mean load according to the lower limit of the minimum value of the converted model; (8) performing rain flow reconstruction on the amplitude and mean of the corrected load cycle; and (9) qualitatively comparing the time series load data characteristics of the original model and the converted model. The method solves the problem of difficulty in repeatedly collecting the time series loads of the mast of a rotary drilling rig of different models.

The intelligent excavation type loader comprises an excavation type loader body, a dust falling mechanism is arranged on the surface of an excavation arm on the side face of the excavation type loader body, the dust falling mechanism comprises a spraying box arranged on the surface of the excavation arm on the side face of the excavation type loader body, and a nozzle is arranged on the side face of the spraying box; through a nozzle anti-blocking cleaning mechanism such as a sweeping strip automatic cleaning and elastic reset dustproof assembly, dust floating objects on the surface and an opening of a nozzle can be actively removed when the dust falling device is idle, the nozzle is prevented from being blocked, losing efficacy and being healthy, it can be ensured that a water mist system normally outputs atomized water flow during hoeing operation, coal dust and rock dust are intercepted in the first time, and the dust falling efficiency is improved. The dust concentration is reduced, the dust suction amount of workers is greatly reduced, the pneumoconiosis risk is reduced, the efficiency level is high, the view blocking caused by dust falling interruption can be avoided, the problems of bucket adjustment delay and material spilling leakage are reduced, the single-time hoeing cycle time is shortened, and the roadway cleaning and material transferring continuity is improved.

The invention discloses a method and a system for testing the service life of a pressure reducing valve of oxygen equipment. The method comprises the following steps: setting a working load cycle and a temperature load cycle of the pressure reducing valve; wherein the working load cycle comprises single service life test cycle time and the working load cycle number of the service life test; the temperature load cycle comprises a temperature cycle consisting of a high-temperature section, a normal-temperature section and a low-temperature section; and carrying out a life test according to the working load cycles and the temperature load cycles, carrying out the temperature load cycles in each working load cycle, and detecting the performance of the pressure reducing valve, and comparing the performance with expected performance. The working load cycle and the temperature load cycle are simultaneously applied in the service life test of the pressure reducing valve, so that the actual use load of the pressure reducing valve can be more truly simulated, the performance of the pressure reducing valve is compared with an expected effect in each working load cycle, the service life and the performance of the pressure reducing valve of oxygen equipment can be more fully verified, and the test efficiency is improved. The verification reliability is improved, and the fault probability of the oxygen equipment is reduced.

The invention relates to a spring fatigue life test method and system. The spring fatigue life test method comprises the following steps: synchronously acquiring an instantaneous force signal and an instantaneous displacement signal of a tested spring, and identifying and obtaining each loading cycle based on the instantaneous force signal and the instantaneous displacement signal; on the basis of the instantaneous force signal and the instantaneous displacement signal corresponding to each loading cycle, characteristic parameters reflecting the mechanical response characteristics of the spring are extracted; tracking the change trend of the characteristic parameters along with the loading cycle times, and calculating according to the change trend of the characteristic parameters to obtain the change rate of the characteristic parameters; and judging the fatigue failure point of the spring according to the change trend and the change rate. The reliability of a fatigue life test result can be remarkably improved, and accurate data support is provided for design optimization of the spring.

The application provides a door and window processing parameter optimization method and system, relates to the door and window processing field, and obtains door and window parameters and external environment information, establishes a door and window simulation model according to the door and window parameters, converts the external environment information into physical load parameters, then performs accelerated simulation operation on the door and window simulation model based on the physical load parameters, obtains door and window performance evaluation results, and finally generates door and window design optimization information according to the evaluation results, and simulates the long-term performance of the door and window within a preset time period by applying multiple frequency load cycles. Through the technical scheme, the application can effectively solve the problem that the existing technology lacks accurate prediction and evaluation capability for the small local deformation of the super-large size and slender profile door and window under the long-term complex environment and the cumulative influence of the small local deformation on the long-term reliability and optical quality of the door and window, and avoids the performance attenuation and quality problems that may occur in the actual application of the traditional method.

The invention discloses a steam turbine system for improving wide-load cycle efficiency based on a regenerative small machine and an operation method thereof. The steam turbine system comprises a pressurization module, and the pressurization module comprises the regenerative small machine, a pressurization cylinder and a water supply secondary heater; the pressure cylinder and the high-pressure cylinder are coaxially arranged; the main steam pipeline comprises a pressure cylinder branch and a high-pressure cylinder branch; a first steam exhaust port and a second steam exhaust port of the pressure cylinder are connected with a high-pressure cylinder branch and a water supply secondary heater through a first steam exhaust pipeline and a second steam exhaust pipeline respectively; a first steam exhaust valve and a second steam exhaust valve are respectively arranged on the first steam exhaust pipeline and the second steam exhaust pipeline; a high-pressure cylinder steam inlet valve is arranged on the high-pressure cylinder branch between the pressure cylinder branch and the first steam exhaust pipeline; a steam inlet of the regenerative small machine is connected with a first steam exhaust pipeline and a high-pressure cylinder steam extraction opening through a first steam inlet branch and a second steam inlet branch which are connected with the steam inlet main pipe in parallel. A first steam inlet valve and a second steam inlet valve are respectively arranged on the first steam inlet branch and the second steam inlet branch; and the steam inlet end of the first steam inlet branch is connected to the first steam exhaust pipeline between the steam exhaust port of the pressure cylinder and the first steam exhaust valve.

This application relates to a method and system for testing the fatigue life of a spring. The method includes: simultaneously acquiring instantaneous force and displacement signals of the spring under test, and identifying each loading cycle based on the instantaneous force and displacement signals; extracting characteristic parameters reflecting the mechanical response characteristics of the spring based on the instantaneous force and displacement signals corresponding to each loading cycle; tracking the changing trend of the characteristic parameters with the number of loading cycles, and calculating the rate of change of the characteristic parameters based on the changing trend; and determining the fatigue failure point of the spring based on the changing trend and the rate of change. This invention can significantly improve the reliability of fatigue life test results and provide accurate data support for spring design optimization.

The application discloses a short-term power load prediction method and system based on a graph-enhanced time-frequency double-branch structure and belongs to the technical field of power system load prediction. The application firstly pre-processes a power load sequence, obtains phase-enhanced time sequence characteristics through adaptive time domain inquiry, extracts multi-scale enhanced characteristics through multi-scale convolution, and then inputs the time-frequency double-branch to obtain time domain and frequency domain preliminary prediction results respectively; graph structure modeling is further used to realize variable correlation enhancement and obtain graph-enhanced time-frequency characteristics; finally, adaptive weighted fusion is performed to obtain power load prediction results. The application can accurately model load cycle characteristics, fully excavate variable coupling correlation, significantly improve the precision, robustness and scene adaptation capability of short-term load prediction, and meet the engineering application requirements of new power systems.

The invention relates to an elastic film (1) with at least one core layer (3) based on styrene block copolymers, wherein the at least one core layer (3) is arranged between at least two cover layers (2). The cover layers (2) exhibit elastic properties without activation, and during a first load cycle, the film (1) exhibits a force of less than 3.75 N at an elongation of 160%. For this purpose, a film strip for the load cycle has a width of 25 mm in the MD direction and is fixed at a CD spacing of 25 mm between grippers of a test device, and the film strip is stretched in CD at a speed of 254 mm / min.