US-12625047-B2 - Portable polymer tester and testing method

US12625047B2US 12625047 B2US12625047 B2US 12625047B2US-12625047-B2

Abstract

A portable testing device and method for measuring physical characteristics of a polymeric or elastomeric material is provided. The testing device includes an indenter probe; a drive system for controlling movement of said probe, said drive system comprising a motorized linear slide operatively associated with the probe to advance said probe from a first position to a second position to deform said polymeric or elastomeric material and to facilitate instant or fast retraction of said probe to a predetermined intermediate position between said first and second positions; and a force/displacement measurement system including a first sensor for measuring force at the tip of said probe during contact with said polymeric or elastomeric material and a second sensor for measuring displacement of the probe; and a controller configured to provide control to the force/displacement measurement system and the drive system.

Inventors

Narendra Singh SACHDEV
Jason DEADMAN
Robert Jamieson
Panayotis DRITSAS
Mark Adam CHUDAK
Cesar Antonio BRAVO
Kevin DI CARLO
Daniel Dat Ho
Susan Creber

Assignees

CANDU ENERGY INC.

Dates

Publication Date: 20260512
Application Date: 20200610

Claims (16)

1 . A portable testing device for in-situ measuring physical characteristics of a cable or wire comprising polymeric or elastomeric material, said device comprising: (a) an indenter probe; (b) a drive system for controlling movement of said probe, said drive system comprising a motorized linear slide operatively associated with the probe to advance said probe from a first position to a second position to deform said polymeric or elastomeric material and to facilitate retraction of said probe to a predetermined intermediate position between said first and second positions; (c) a force/displacement measurement system including a first sensor for measuring force at the tip of said probe during contact with said polymeric or elastomeric material and a second sensor for measuring displacement of the probe; (d) a plate heater configured to directly heat a test location of the polymeric or elastomeric material to a set temperature, wherein the test location is located where the indenter probe indents the polymeric or elastomeric material, wherein the plate heater defines a hole through which the indenter probe is configured to advance between the first and second positions; (e) a first temperature sensor configured to measure a temperature of the polymeric or elastomeric material at the test location; (f) a sample retaining assembly including a clamp for immobilizing all or a portion of the material during in-situ measurement, and a clamp control module configured to receive clamp force data from a third sensor indicating the force between the clamp and the polymeric or elastomeric material, and to move the clamp to maintain a set force between the clamp and polymeric or elastomeric material, wherein the clamp comprises a moveable clamping jaw and a stationary clamping member, wherein the clamp is configured to secure the polymeric or elastomeric material between the moveable clamping jaw and the stationary clamping member, the stationary clamping member comprising the hole through which the indenter probe is configured to advance between the first and second positions; and (g) a controller configured to: (i) provide control to the force/displacement measurement system, the drive system, the clamp, and the plate heater; (ii) receive data from the first temperature sensor of the temperature of the polymeric or elastomeric material at the test location; (iii) receive data from the third sensor indicating the force between the clamp and material; and (iv) send data to instruct the plate heater to heat the polymeric or elastomeric material at the test location to a desired temperature; (v) in response to the data received from the third sensor, send data to instruct the clamp to maintain the set force between the clamp and said polymeric or elastomeric material; (vi) send data to instruct the indenter probe to deform the test location of said polymeric or elastomeric material.
2 . The portable testing device of claim 1 , wherein the motorized linear slide is a piezo-electric motor, and a ball screw drive or linear actuator; or the motorized linear slide is a direct current servo drive and a ball screw drive.
3 . The portable testing device of claim 1 , wherein controller is configured to: (b) calculate a specific compressive stiffness of the polymer material from measured displacement of the probe and measured force at the tip of said probe during deformation or at maximum indentation of said polymer material; (c) hold said probe to a predetermined indentation depth to allow for force relaxation; and (d) retract said probe to a predetermined intermediate position out of contact with the deformed polymer material and measuring time of recovery of deformation until contact of said polymer material with said probe reoccurs; wherein the specific compressive stiffness and the time of recovery of deformation are indicators of degree of polymer aging.
4 . A method for testing a polymer material aging comprising the steps of: (a) providing the portable testing device of claim 1 ; (b) heating the test location with the heater to a set temperature; (c) deforming the test location of the polymer material using a probe; (d) calculating specific compressive stiffness of the polymer material from measured displacement of the probe and measured force at the tip of said probe during deformation or at maximum indentation of said polymer material; (e) holding said probe to a predetermined indentation depth to allow for force relaxation; and (f) retracting said probe to a predetermined intermediate position out of contact with the deformed polymer material and measuring time of recovery of deformation until contact of said polymer material with said probe reoccurs; wherein the specific compressive stiffness and the time of recovery of deformation are indicators of degree of polymer aging.
5 . The method claim 4 , wherein measuring time of recovery until contact of said polymer material with said probe reoccurs comprises identifying the time between retracting said probe and recording a force value above zero.
6 . The method of claim 4 , wherein calculating the specific compressive stiffness comprises measuring displacement of a linear encoder.
7 . The method of claim 4 , comprising securing the material with a clamp, and modifying the force between the clamp and the material to maintain a set force.
8 . The method of claim 4 , comprising detecting a surface of the polymer material by extending the probe into contact with the polymer material to identify a zero position, and a preload phase comprising preloading said probe a distance into said polymer material from the zero position, and an indentation phase comprising advancing said probe to deform said polymer material while measuring force at the tip of said probe during deformation.
9 . The method of claim 4 , comprising preloading a tester device of claim 1 with test parameters for the polymer material, the test parameters comprising at least one of indentation depth, temperature, clamping force, preload distance, and retraction depth.
10 . A method of predicting remaining life of a polymer comprising: (a) providing the portable testing device of claim 1 ; (b) testing the polymer to determine an indenter modulus (IM) or recovery time (RT) value; (c) comparing the IM or RT value with benchmark data of the polymer; (d) calculating a predicated value of the remaining life of the polymer by correlating the indenter modulus or recovery time value with the benchmark data of the polymer to determine a rate of deterioration; and by calculating the predicated value of the remaining life using the rate of deterioration to an end of life value for indenter modulus or recovery time.
11 . The method of claim 10 , comprising updating the benchmark data with the IM or RT value.
12 . The portable testing device of claim 1 , comprising a linear encoder located on a non-deflecting part of the drive system for measuring the indenter probe position.
13 . The portable testing device of claim 1 , wherein the plate heater is the stationary clamping member.
14 . The portable testing device of claim 1 , wherein the first temperature sensor is a contactless infrared thermocouple positioned to measure the test location surface prior indentation by the probe.
15 . The portable testing device of claim 1 , wherein the controller is configured to receive a historical temperature value, send data to the plate heater to heat the test location to the historical temperature value; and send the data to the drive system to deform the polymeric or elastomeric material at the test location using the probe when the test location is at the historical temperature.
16 . The portable testing device of claim 1 , wherein the controller is configured to: send data to the plate heater to heat the test location to a first temperature; send data to the drive system to deform the polymeric or elastomeric material at the test location using the probe when the test location is at the first temperature; receive data from the first and second sensors of the force at the tip of the probe and the displacement of the probe when the test location is at the first temperature; send data to the plate heater to heat the test location to a second temperature; send data to the drive system to deform the polymeric or elastomeric material at the test location using the probe when the temperature at the test location is at the second temperature; and receive data from the first and second sensors of the force at the tip of the probe and the displacement of the probe when the temperature at the test location is at the second temperature.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims all benefit including priority to U.S. Patent Application No. 62/882,469, filed Aug. 2, 2019, and entitled, “PORTABLE POLYMER TESTER AND TESTING METHOD”, the entirety of which is hereby incorporated by reference. FIELD The present disclosure pertains to the field of polymer material testing and, more particularly to the field of portable polymer testers for in-situ monitoring of polymer-based components. BACKGROUND The aging of polymers is of considerable importance to, among others, aerospace, oil & gas, industrial, electrical power plant operators, or any industry where unplanned failures can risk public safety or have severe financial consequences, in that the unanticipated failure of such polymers may have significant adverse effects on human safety, plant operation and maintenance costs and downtime. Polymers are used in key components related to the safe and reliable operation of industrial and power plants. Specifically, polymers are found in, but not limited to; cables, pumps, valves and seals. Electrical and optical cables, such as power, control, instrumentation and data transmission have traditionally been considered long-lived components which merit little in the way of preventive maintenance or condition monitoring due to their generally high level of reliability and simplicity of construction. Like all other components, however, such cables age as a result of operational and environmental stressors. The typical modes of degradation due to cable aging are embrittlement leading to cracks, loss of dielectric strength, and increased leakage current. The main stressors causing age-related degradation are thermal aging resulting from elevated temperatures, ionising radiation, and neutron radiation. Other degradation stressors of cables include mechanical stresses, humidity, hydrocarbon fluids, and ozone. SUMMARY Based on the foregoing, there remains a need for a method and device for monitoring and estimating the aging of polymer cable, which method and device is portable, non-destructive and permits optimization and measurement of characteristics other than merely polymer stiffness. The present disclosure describes a portable polymer tester. In accordance with one aspect, there is provided a method and device for indenting polymer material, such as cable insulation or cable jacket material, to generate indentation and post-indentation parameters that characterize the visco-elastic properties of the polymer material tested. The visco-elastic properties are used as an indicator of polymer age and degradation. The method and device of the present disclosure measures stiffness (measurement of force and displacement) of polymeric material, as well as the time taken by the polymeric material to recover a set portion of the initial deformation. This duration can be used as an indicator of polymer material degradation. In accordance with another aspect, there is provided a polymer tester for measuring physical characteristics of a polymer material, such as a polymer jacket of a cable, said polymer tester comprising: jaw assemblies for retaining a sample, such as a cable or a flat elastomeric sample, during testing; an interchangeable and moveable probe; a drive system for advancing the probe to contact and deform the polymer jacket of the cable, said drive system comprising a motor and a linear slide; and a force/displacement measurement system including a mechanism for measuring force at the tip of said probe during contact with said polymer jacket and means for measuring displacement of the probe. In an embodiment, the testing device may comprise a heater configured to heat a test location of the polymeric or elastomeric material to a set temperature. In another embodiment, the testing device may comprise a linear encoder located on a non-deflecting part of the drive system. In an embodiment, the linear encode is located proximate to the tip of the indenter probe for measuring the indenter probe position. In another embodiment, the motorized linear slide of the testing device is a direct current servo drive and ball screw drive. In anther embodiment, the motorized linear slide of the testing device is piezo-electric motor and a ball screw drive or linear actuator. In another embodiment, the testing device may comprise a sample retaining assembly including a clamp for immobilizing all or a portion of the material during testing, and a clamp control module configured to receive clamp force data from a load cell indicating the force between the clamp and material, and to move the clamp to maintain a set force. In another embodiment, the polymer tester may comprise a controller comprising an control software program for providing control to the force/displacement measurement system and the drive system. The controller may be configured to be loaded in advance of testing with operating parameters to set at least one of a force measurement range, a