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User Benefits Application News Tensile Test of Plastics with Automatic Extensometer Compliance with ISO 527 (JIS K 7161) regulation Significant test time reduction S. Bressan Precision Universal Testing Machine AGX™-V Introduction Plastic materials have excellent formability and versatility, and are widely employed as structural/functional material in several fields ranging from aircraft parts to electronic components. During the design/quality control phase, the measurement of the material mechanical properties is essential to ensure high reliability and safety of the products. The typical material properties are the tensile strength and the elastic modulus, both evaluated with a tensile test. Such tests must be conducted following the guidelines of regulations (national or international) in order to guarantee a high repeatability and reliability of the measurements. When tensile tests are conducted for quality control, numerous tests must be repeated every day and a reduction of the test time is key to optimize the inspection process. Effective methods to reduce the test time include the employment of extensometers capable of setting the arm position and grip the specimen automatically, such as the SIE-560SA. In this work, the precision universal testing machine AGX-10kNVD and the automatic extensometer SIE- 560SA were employed to test 3 varieties of plastic materials (PVC, PP, PC) according to the ISO 527 (JIS K 7161) standard. Test Method The tests have been conducted following the guidelines of the ISO 527 (JIS K 7161) regulation. The shape and size of the specimens are shown in Fig. 1. The tests speed has been set to 1 mm/min for a strain below 0.3% and 50 mm/min when the strain reached the value of 0.3%. The strain interval for the calculation of the Elastic modulus E t was 0.05%~0.25% (Fig. 2). The tensile strength σ m is defined as the highest stress recorded during the test. Accordingly, in the case that the tested material exhibits a clear yielding point, the tensile strength σ m becomes the stress in correspondence of the yielding strain, σ y . Fig. 1 Specimen Shape and Size Test Equipment The tests have been conducted using a 10 kN universal precision testing machine AGX-10kNVD and the measurement of the strain was performed with the automatic extensometer SIE-560SA. The main features of the SIE-560SA are listed below ・Automatic position adjustment and closing/removal of the arms. ・Measurement of the strain until rupture of the specimen. ・Strain measurement accuracy suitable for tests according to ISO 527 (JIS K 7161) regulation (the higher between ±1μm or 0.5% of the measured stain). Fig. 2 Elastic Modulus E t Calculation Fig. 3 Test Equipment
Application News www.shimadzu.com/an/ Shimadzu Corporation Analytical & Measuring Instruments Division Global Application Development Center © Shimadzu Corporation, 2021 For Research Use Only. Not for use in diagnostic procedures. This publication may contain references to products that are not available in your country. Please contact us to check the availability of these products in your country. The content of this publication shall not be reproduced, altered or sold for any commercial purpose without the written approval of Shimadzu. See http://www.shimadzu.com/about/trademarks/index.html for details. Third party trademarks and trade names may be used in this publication to refer to either the entities or their products/services, whether or not they are used with trademark symbol “TM” or “”. The information contained herein is provided to you "as is" without warranty of any kind including without limitation warranties as to its accuracy or completeness. Shimadzu does not assume any responsibility or liability for any damage, whether direct or indirect, relating to the use of this publication. This publication is based upon the information available to Shimadzu on or before the date of publication, and subject to change without notice. First Edition: Jun. 2021 01-00141-EN Table 1 Details of the Test Equipment Test Results The relationship between stress and strain graph is represented in Fig. 5. Each material exhibited a clear yield point, and therefore the tensile strength σ m has been evaluated as the yield stress σ y . The detection of the yield strength is conducted automatically with the software TRAPEZIUMX-V. The test results are shown in Table 2. Conclusion The tensile strength and the elastic modulus of three types of plastic materials were measured by using a precision universal testing machine AGX-10kNVD and an automatic extensometer SIE-560SA. By using the SIE-560SA and a pneumatic type grip, a significant test time reduction can be achieved allowing to conduct highly efficient measurements. In addition, the high precision of the SIE- 560SA makes it suitable for tests compliant with the ISO 570 (JIS K 7161) regulation. Fig. 5 Stress-Strain Graphs (a. PVC, b. PC, c. PP) TRAPEZIUM and AGX are trademarks of Shimadzu Corporation in Japan and/or other countries. Fig. 4 Schematic View of the Test Table 2 Test Results For this test, 5kN pneumatic flat grips were employed. The opening/closing of these grips is air driven and drastically facilitate the specimen setup, further contributing to the reduction of the test time. The details of the test equipment are summarized in Table 1. A schematic view of the test is shown in Fig. 4.