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Failure analysis and material control

Compliance with ISO 6892 Metallic Material Count on Shimadzu for Satisfying Plastic Testing Standards
Tensile Testing Standards – Three Key Points for Satisfying ISO 178, JIS K 7171, ISO 527, JIS K 7161 Requirements –

– Autotuning Function Makes It Easy to Achieve ISO 6892 Strain Control –
ISO 6892 was revised in 2009, with additional requirements for high precision strain control (Method A). Similarly, JIS Z 2241 was also revised in 2011, Both ISO 178, JIS K 7171 (plastic flexural properties) and ISO 527, JIS K 7161 (plastic tensile properties) have been revised. As the global demand for
but does not include high precision strain control requirements. plastics continues to increase, it is increasingly important to (1) understand the strength properties of those plastics, (2) comply with international testing
However, for global compliance, both ISO 6892 and JIS Z 2241 must be satisfied. standards, and (3) confirm data reliability.
Description
Strain Rate with Higher Testing Speed Accuracy Required Satisfying Testing Speed Requirements Requires the Following
Key Points for ISO 178 and JIS K 7171 Compliance
Test force Rate Range Setting optimal gain level is important!
JIS Z 2241 (previous)
(1) A bending deflectometer is required for all measurements.
A: Rate of increase in stress (2 to 30 MPa/s) Good gain setting: Accuracy within ±1 % of indicated value is required for all displacement measurements until tests are finished.
B: Predicted strain rate (0.3 to 0.8 %/sec) S = G (F – M)
Applicable S: Control signal For example, accuracy to within ±3.4 µm is required for measuring the flexural modulus of a 4 mm thick sample.
ISO 6892 (previous) signals Target value F Measurement F: Target signal
value M
• Test force (control result) M: Current measurement value (2) If testing is performed using compliance correction, ISO 178 recommends using an instrument with high rigidity.
A: Rate of increase in stress (2 to 60 MPa/s)
• Stroke Appropriate gain setting G: Control loop gain As for (1), the regulation includes the following note, which clearly states that use of crosshead displacements for measurements is not recommended.
A B Displacement B: Predicted strain rate (0.25 to 0.8 %/sec) • Elongation F - M: Control deviation "The crosshead displacement includes not only the specimen deflection but also the indentation of the loading edge and the supports into the specimen
Time
and deformation of the machine. The last of these is machine-dependent as well as load-dependent. Results determined on different types of machine are
Test force Constant Rate Enables testing at specified speed.
ISO 6892 (Method A) Poor gain setting: therefore not comparable."
A: Strain rate (0.025 %/sec ±20 %)
Applicable Target value F Applicable Target value F
B: Predicted strain rate (0.67 %/sec ±20 %) signals signals Key Points for ISO 527 and JIS K 7161 Compliance
In revisions to ISO 6892 (Method A) Also includes the following patterns: • Test force Measurement • Test force (1) An extensometer with an absolute accuracy of 1 µm is required.
Predicted strain rate for Strain rate (0.007 %/sec ±20 %) • Stroke value M • Stroke Control
discontinuous yield points • Elongation (control result) • Elongation deviation Along with addition of a 75 mm gauge length, an extensometer with an absolute accuracy of 1.5 µm is required for the newly added 75 mm gauge length
Predicted strain rate (0.2 %/sec ±20 %) Control deviation Measurement
value M
A B Displacement (control result) and an extensometer with an absolute accuracy of 1 µm is required for the 50 mm gauge length.
High gain setting Time Low gain setting Time (2) An instrument with a fast sampling rate is required.
Results in speed instability. Testing speed never increases. According to the testing standards, a data acquisition sampling rate must be at least as high as the sampling frequency calculated based on the following conditions.
ƒ : Sampling frequency (Hz)
Shimadzu Precision Universal Testing Machines / Universal Testing Machines v Lo : Test speed (mm/min)
: Gauge length (mm)
For example, given a testing speed v = 1 mm/min, L : Grip space (mm)
a sampling frequency ƒ of 22 Hz (46 msec) is required. R : Minimum extensometer resolution (mm)
Revisions to ISO 6892 (Metallic Tensile Testing Standards) Revisions to ISO 6892 (Metallic Tensile Testing Standards) (Lo = GL = 75 mm, L = 115 mm, r = 0.0005 mm) (where, resolution is at least half the extensometer accuracy)
Satisfying Testing Speed Requirements Class 1 Extensometers Required
(3) A post-yield strain calculation method was added.
A new formula (Method B) was added for calculating nominal strain in plastics, which exhibit yield characteristics.

Tensile Testing Automatic Gauge SSG Series Gauge Length TRViewX Series Contact-Type
Length Extensometer Extensometer Non-Contact Digital Bending Deflectometer AGX-V Series
AGX-V Series UH-X/UH-FX Series SIE-560A Series (supports GL settings) (Supports 50 and 75 mm GLs) Video Extensometer (ISO 178-compliant) Precision Universal Tester
Precision Universal Tester Universal Testing Machines AEH3 Contact-Type Automatic Extensometer
· Shimadzu offers testing systems that are compliant with ISO testing standards.
Strain Rate Control Automatic and Manual Extensometers
Strain rate control on the AGX-V guarantees the precision level (±20 %) specified in ISO Strain control requires a Class 1 extensometer. Strain control specified in ISO 6892 requires an ISO 178-compliant bending deflectometer: Satisfies the accuracy of ISO 9513 Class 1, with absolute accuracy to within 1 % of deflection.
6892. The AGX-V offers eight times higher control precision than previous models and extensometer with Class 1 accuracy. In some cases, the extensometer structure prevents
features an autotuning function that allows precise strain rate control without having to high-precision strain control, even for extensometers with Class 1 accuracy. ISO 527-compliant gauge length extensometer: Absolute accuracy to within 1 µm (accuracy required for 50 mm gauge length)
specify parameter settings or perform preliminary tests, regardless of the sample material or The AEH automatic extensometer and SSG and SSG-H manual extensometers
history. guarantee Class 1 accuracy capability and, therefore, can be used for strain control. ISO 178 and ISO 527-compliant software: Standard functionality is compliant with data analysis requirements, such as for
Starting from the UH-X universal testing machine, the universal testing machines offer Class 1 accuracy is also guaranteed for low-cost SG manual extensometers, but they elastic modulus and post-yield strain measurements.
higher stroke displacement resolution and guarantee ±20 % precision level of strain rate do not support strain control. The reason is because the extensometer structure affects · Ensures testing machine traceability.
control using a semi-autotuning function, which does not require setting parameters. the control precision at high-precision strain rates.
Test force calibration: Compliant with JCSS (JIS B 7721-compliant) and ASNITE (ASTM E4-compliant) calibration.
Extensometer calibration: JCSS-compliant (ISO 527-compliant) extensometer calibration service started in 2014. An industry first!
· Strain rate control precision on the AGX-V is within ±20 %. · Strain control specified in ISO 6892 requires a Class 1
· Strain rate control can be performed easily using the extensometer. Calibration certificate: Test force calibration certificates can also be prepared marked with a JCSS or ASNITE logo.
autotuning function. · JIS Z 2241 requires an extensometer with Class 2 or higher · Helps improve testing efficiency.
· Strain rate control precision on the UH-X is within ±20 %. accuracy. ISO 178: Supports measurements using a room-temperature or thermostatic chamber automatic bending testing
· Compatible manual extensometers include the SSG and SSG-H. machine and bending deflection gauge attachment.
It is important to note the extensometer class.
ISO 527: Shimadzu has extensive track record with automatic tensile testing machines.
Shimadzu also provides data processing software linked to testing machines. Many of these software programs allow
result data to be transmitted to a higher-order device.
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