Investigation of a full field of material properties and inverse identification of constitutive parameters of pipeline steel using DIC

Purpose In recent years, there has been increasing interest in the measurement of material properties under specific conditions, such as the measurement of microspecimens. The analysis of materials with specific properties concentrated in a small volume is becoming increasingly important. Manufacturing and measurement of microsamples are complex and often require specialized equipment. Therefore, the paper aims to propose a solution to the problem of microspecimens using notched specimens and inverse identification of constitutive parameters. Design/methodology/approach First, calibration measurements were made with notched specimens from S355 steel. Afterward, the discussed welded joint was first investigated by the uniform stress method. Consequently, several notched specimens were manufactured from different areas of the weld. The full strain field was measured using the digital image correlation (DIC) method. Subsequently, the constitutive parameters of the material between the notches were inversely identified. Findings The proposed approach of inverse identification of constitutive parameters by using notched specimens and full-field strain measurements appears to be a suitable method for evaluating the properties of materials that are concentrated in a small volume. The proposed approach is easy to use and straightforward. The strain data used for the identification are only from a line in the narrowest cross-section. Originality/value The paper presents the use of DIC with notched specimens to investigate the constitutive parameters and conventional material properties of a material concentrated in a small volume without the need to use microspecimens. Hence, unlike other inverse identification methods that use a 2D strain field, the proposed method uses only a 1D strain field. Thus, the used strain field lies only in the identified material.