The main goal of this paper is to present a robust calibration procedure of essential material parameters of concrete models, based on both full-field measurements and inverse analysis. The proposed method uses a simple laboratory test and home-made correlation software alongside a fast camera. Usually, a full set of material model parameters of concrete can be determined through application of several different tests and specimen conditions. A recent method requires just one test for identification of most of the model constants. It reduces the time needed for testing and provides a relatively fast calibration of the selected parameters through minimization of discrepancies both of experimentally measured displacement fields on the specimen surface and of the numerically computed corresponding quantities. A study of an efficient correlation algorithm and of a reliable minimization gradient-based algorithm is also presented.
Different kind of foams, usually made from polymers, metals, ceramics, glass, etc. have been widely used in various branches of civil engineering since the 80s. The most common are polyurethane foams. Since their role in construction nowadays is not only to act as a thermal barrier but also to take some of loads, the engineers need to know also their mechanical properties. This implies that manufacturers or designers must perform a number of laboratory tests in order to find a set of substantial parameters of this particular material. Due to noticeable orthotropic behavior of foams, one needs to carry out several laboratory tests to identify elastic properties only. Here, an enhanced testing methodology is proposed to reduce the number of tests required for characterization of elastic orthotropic properties of foams. By combining the advanced measurement techniques, non-traditional experimental setup, numerical modeling and inverse analysis one can capture all nine elastic properties from just two or three tests. In the paper, full experimental and numerical procedures are presented and validated by noisy pseudo-experimental data.
Zaprezentowano mikrostrukturę oraz badania mechaniczne spawów cienkich blach z superstopów na bazie niklu: Haynes 230 i Hastelloy X. Spoiny wykonano metodą mikrospawania opornościowo-impulsowego z wykorzystaniem urządzenia WS 7000S. Mikrotwardość złączy zmierzono twardościomierzem Matsuzawa Vickers MX 100 przy obciążeniu 100 G (0,98 N). Obserwacje metalograficzne przygotowanych zgładów przeprowadzono za pomocą mikroskopu optycznego Nikon Eclipse MA200 przy różnych powiększeniach. Badania mikrostruktury metalograficznej uzupełniono analizą liniową składu chemicznego. Wykorzystano do tego mikrosondę elektronową typu OXFORD X-MAX.
EN
Microstructure and mechanical tests of welds of thin sheets made from nickel-based super-alloys (Haynes 230 and Hastelloy X) were presented. The welds were made using the resistive-pulse micro-welding method using the WS 7000S device. The micro-hardness of the joints was measured with a Matsuzawa Vickers MX 100 hardness tester at 100 G (0.98 N). Metallographic observations of the prepared micro-sections were performed using the Nikon Eclipse MA200 optical microscope at various magnifications. The metallographic microstructure studies were supplemented by linear analysis of the chemical composition, for which the OXFORD X-MAX electron microscope was applied.