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Metal membranes are defined as thin steel circular plates. The metal membranes are widely used in the measurement technique and they are constantly loaded over the entire surface. In case that a membrane is loaded with uniform load over the entire surface. In case that the membrane is stiffened over the edge, then it is called a diaphragm. According to the making method membranes are divided into flat and corrugated. Corrugated membranes are used mainly in a low pressure area. Membranes are most commonly made of firm alloy austenitic steel. In this paper numerical and experimental analysis of a thin corrugated diaphragm 24 mm diameter is presented, with variable material thickness and variable corrugations geometry. Experimental tests are conducted on a corrugated stainless steel (AISI 316) diaphragm. Experimental results are compared with numerical results in ANSYS software package. A comparative analysis of the sinusoidal and toroidal diaphragms has shown that there is a higher sensitivity of the sinusoidal diaphragm, that is, if the thickness of the diaphragm increases, and their stiffness is increased. In general, for small pressure ranges from 10 mbar to 50 mbar, the sinusoidal diaphragms have a faster response.

Research presented in this paper involves the numerical simulation of crack growth in a welded joint made of common structural steel S235JR2, but with the presence of a number of different welding defects, which represents a scenario that is not covered by relevant standards, in this case EN ISO 5817. After analysing several defect combinations, which could occur in reality, the one with the least favourable combination of stress concentration and plastic strain was selected as the relevant model. A crack was then introduced in the location where the stresses, caused by tensile loading of the welded joint model, were above the yield stress. The numerical analysis performed in this case involved different combinations of load magnitudes and crack length, in order to determine at which point the initial crack will start propagating.

This paper is devoted to the ductile–brittle transition behavior of high strength low alloyed structural steel NIOMOL 490K. This steel grade is designed for welded pressure vessels exposed to dynamic loads, operating at temperatures below zero, and that is why it must have acceptable toughness. Due to its importance for the safety assessment of pressure vessels, a characterization of this steel with Charpy V-notch test in range of temperature between-60 ⁰C and +60 ⁰C was undertaken. Ductile-to-brittle transition temperature curves were generated in the present study by using instrumented Charpy pendulum impact test on V-notch specimens. Notches were located in the parent material, heat-affected zone and weld metal. The nil-ductility temperature and tensile properties in temperature range from -60 ⁰C to +60 ⁰C are presented in this paper. We used different test temperatures to better understand ductile-to brittle transition response than just use either Charpy energy or other related ductility criteria.

This paper is based on extensive research about the influence of multiple different welded joint defects on the integrity of welded structures. In this particular case, the focus was on the heat affected zone and its different sub regions - up to this point, it was observed as a whole, with homogeneous mechanical properties along its cross-section. Due to the need to describe its behaviour in more detail, it was concluded that metallographic characterisation of the heat affected zone is necessary. Metallographic tests have provided a detailed insight into the micro-structures with the heat affected zone, which would be difficult to predict in this case, due to specific conditions, i.e., a welding technology which was adopted with the purpose of deliberately causing a number of defects in the welded joint. This would result in a more realistic distribution of mechanical properties along the heat affected zone, which in turn would provide more accurate input data for numerical simulations, since the use of finite element method will be the next step in this research.

One of the most important aspects of materials typically used in biomedical engineering is their resistance to various unfavourable exploitation conditions, which greatly impact their work life. In terms of extreme conditions, two major factors include fatigue and corrosion, and a combination of these can significantly decrease the expected life of various implants. The focus of this paper will be on hip implants made of Ti-Al6-4V titanium alloy, a material commonly used in such applications, due to its resistance to corrosion and bio-compatibility. Research shown here was based on experimental testing of said alloy in order to determine its mechanical properties under different working environments, including normal, salty and wet conditions. These properties were then used as input data for Extended Finite Element method (XFEM) numerical simulations of fatigue crack growth in hip implants with various geometries. This was of particular interest since specimens which were kept in salty and wet environment had a slight degradation of yield stress and tensile strength, but an increase in plasticity.