Assessment of the Structural Integrity of the Portal Crane Elements After Long-Term Operation.

Evaluating the current technical condition and residual life of structures that may have reached or exceeded the end of their design life is a challenging issue in many industrial sectors. This paper focuses on the assessment of the structural integrity of structural elements of a seaport portal crane after operation for about 33 years. Test specimens were extracted from two crane elements, a jib (element A) as the most seriously loaded unit and, for comparison, a boom (element B) as the less loaded one, and machined in two different orientations, longitudinal and transversal.

Specimen Size Effect on the Tensile Properties of Rolled Steel of Long-Term-Operated Portal Crane.

This paper presents the research results on the mechanical behavior of the low-carbon rolled steel of a sea portal crane after a 33-year operation depending on the operational stresses and rolling direction in order to assess its serviceability. The tensile properties of steels were investigated using rectangular cross-section specimens with different thicknesses and the same width. Strength indicators were slightly dependent on the considered factors (operational conditions, the cutting direction, and thickness of specimens).

Identification of the Fracture Process in Gas Pipeline Steel Based on the Analysis of AE Signals.

The paper presents the results of tests conducted to identify the damage process in specimens collected from the steel of a gas pipeline. The tests concerned specimens made of S235 steel subject to quasi-static loading-uniaxial tension until failure. Acoustic emission (AE) signals were recorded during the loading process along with force and elongation signals.

Evaluation of Corrosion, Mechanical Properties and Hydrogen Embrittlement of Casing Pipe Steels with Different Microstructure.

In the research, the corrosion and mechanical properties, as well as susceptibility to hydrogen embrittlement, of two casing pipe steels were investigated in order to assess their serviceability in corrosive and hydrogenating environments under operation in oil and gas wells. Two carbon steels with different microstructures were tested: the medium carbon steel (MCS) with bainitic microstructure and the medium-high carbon steel (MHCS) with ferrite-pearlite microstructure. The results showed that the corrosion resistance of the MHCS in CO-containing acid chloride solution, simulating formation water, was significantly lower than that of the MCS, which was associated with microstructure features.

Assessment of Operational Degradation of Pipeline Steels.

This paper summarizes a series of the authors' research in the field of assessing the operational degradation of oil and gas transit pipeline steels. Both mechanical and electrochemical properties of steels are deteriorated after operation, as is their resistance to environmentally-assisted cracking. The characteristics of resistance to brittle fracture and stress corrosion cracking decrease most intensively, which is associated with a development of in-bulk dissipated microdamages of the material.

On Characteristics of Ferritic Steel Determined during the Uniaxial Tensile Test.

Tensile uniaxial test is typically used to determine the strength and plasticity of a material. Nominal (engineering) stress-strain relationship is suitable for determining properties when elastic strain dominates (e.g.

Using AE Signals to Investigate the Fracture Process in an Al-Ti Laminate.

The paper describes tests conducted to identify the mechanisms occurring during the fracture of single-edge notches loaded in three-point bending (SENB) specimens made from an Al-Ti laminate. The experimental tests were complemented with microstructural analyses of the specimens' fracture surfaces and an in-depth analysis of acoustic emission (AE) signals. The paper presents the application of the AE method to identify fracture processes in the layered Al-Ti composite using a non-hierarchical method for clustering AE signals (k-means) and analyses using waveform time domain, waveform time domain (autocorrelation), fast Fourier transform (FFT Real) and waveform continuous wavelet based on the Morlet wavelet.

Investigation of the Fracture Process of Explosively Welded AA2519-AA1050-Ti6Al4V Layered Material.

The study presents an analysis of the cracking process of explosive welded layered material AA2519-AA1050-Ti6Al4V (Al-Ti laminate) at ambient (293 K) and reduced (223 and 77 K) temperatures. Fracture toughness tests were conducted for specimens made of base materials and Al-Ti laminate. As a result of loading, delamination cracking occurred in the bonding layer of specimens made from Al-Ti laminate.

Influence of LWE on Strength of Welded Joints of HSS S960-Experimental and Numerical Analysis.

This paper presents a strength analysis of joints made during high-strength steel S960 welding. Joints obtained by conventional and laser welding were tested. The most attention was focused on assessing the strength of the material at Heat Affect Zone (HAZ).

Fracture Mechanisms of S355 Steel-Experimental Research, FEM Simulation and SEM Observation.

In this study, the fracture mechanisms of S355 ferritic steel were analyzed. In order to obtain different mechanisms of fracture (completely brittle, mixed brittle and ductile or completely ductile), tests were carried out over a temperature range of -120 to +20 °C. Our experimental research was supplemented with scanning electron microscopy (SEM) observations of the specimens' fracture surfaces.

The Use of the Acoustic Emission Method to Identify Crack Growth in 40CrMo Steel.

The article presents the application of the acoustic emission (AE) technique for detecting crack initiation and examining the crack growth process in steel used in engineering structures. The tests were carried out on 40CrMo steel specimens with a single edge notch in bending (SENB). In the tests crack opening displacement, force parameter, and potential drop signal were measured.

Estimation of the Onset of Crack Growth in Ductile Materials.

In this paper, the ductile fracture mechanism is discussed. The results of numerical and experimental analyses were used to estimate the onset of crack front growth. It was assumed that the ductile fracture in front of the crack starts at the location along the crack front where the accumulated effective plastic strain reaches a critical value.