40th International Conference on Production Engineering of Serbia
ICPES 2025
Nis, Serbia, 18-19th september 2025
ASSESSMENT OF MEASUREMENT UNCERTAINTY IN MECHANICAL MATERIAL TESTING – THEORETICAL FRAMEWORK AND PRACTICAL APPLICATION
Dušan Petkovic, Predrag Jankovic
DOI: 10.46793/ICPES25.183P
This professional paper addresses a fundamental aspect of metrological quality assurance in mechanical material testing: the assessment of measurement uncertainty. Starting from the importance of reliable measurement results for industry, research, and development, the paper thoroughly elaborates on the theoretical framework of measurement uncertainty in accordance with international standards, primarily the GUM (Guide to the Expression of Uncertainty in Measurement) document. Special emphasis is placed on the clear distinction between measurement error and measurement uncertainty, as well as on different evaluation methods (Type A and Type B). General sources of uncertainty characteristic of mechanical testing are discussed, including the influence of equipment, the material/specimen itself, environmental conditions, and human factors.The methodology for assessing measurement uncertainty is presented step-by-step, from defining the measurement model and identifying input quantities, through calculating standard and combined uncertainty, to determining expanded uncertainty. The practical application of this methodology is demonstrated through a specific example of hardness determination by Rockwell method. For this example, key sources of uncertainty are analysed, and guidelines for their quantification are provided.
Mechanical material testing, Measurement uncertainty, Hardness determination, Product quality
[1] SRPS EN ISO 6508-1:2024, Metalni materijali - Ispitivanje tvrdoce po Rokvelu - Deo 1: Metoda ispitivanja, 2024.
ISO/IEC
[2] Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in measurement (GUM: 1995).
[3] ASTM E18, Standard Test Methods for Rockwell Hardness of Metallic Materials.
[4] Guide E.U.R.A.M.E.T. cg-16, Guidelines on the Estimation of Uncertainty in Hardness Measurements.
[ht t p:// www .euramet .org].
[5] Gabauer W., Manual of Codes of Practice for the Determination of Uncertainties in Mechanical Tests on Metallic Materials, The Estimation of Uncertainties in Hardness Measurements, Project, No. SMT4-CT97-2165, UNCERT COP 14: 2000.
[6] Polzin T., Schwenk D. Method for uncertainty determination of hardness testing; PC file for the determination, Materialprüfung, 44 (2002) 3, pp. 64–71.