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The paper aims to shed some light on the effect of the notch/crack‐tip stresses and their role on the cyclic plasticity and crack growth behavior in compression‐compression fatigue.

Compression precracking was studied using 2D finite element analysis for CT specimen. The final crack length and the shape of the crack front were compared with those obtained experimentally.

It has been found that cyclic plasticity and stress redistribution govern the observed fatigue crack growth behavior in compression‐compression precracking. Only the internal stress corresponding to P_max shows a significant redistribution with the crack extension whereas the stress corresponding P_min is not affected by the increase of crack length.

This results are limited to Mode I cracking.

It supports that two thresholds, ΔK^th and K_max^th, govern the fatigue crack behavior. When the contribution from the internal tensile stress is not big enough to make K_max exceed K_max^th the crack will self arrest.

It has been found that cyclic plasticity and stress redistribution govern the observed fatigue crack growth behavior in compression‐compression precracking. The comparison of the numerical results with experimental data in terms of final crack length and crack front shape indicated a fair agreement.

The purpose of this paper is to determine the ultra-high cycle fatigue behavior and ultra-slow crack propagation behavior of selective laser melting (SLM) AlSi7Mg alloy under as-built conditions.

Constant amplitude and two-step variable amplitude fatigue tests were carried out using ultrasonic fatigue equipment. The fracture surface of the failure specimen was quantitatively analyzed by scanning electron microscope (SEM).

The results show that the competition of surface and interior crack initiation modes leads to a duplex S–N curve. Both manufacturing defects (such as the lack of fusion) and inclusions can act as initially fatal fatigue microcracks, and the fatigue sensitivity level decreases with the location, size and type of the maximum defects.

The research results play a certain role in understanding the ultra-high cycle fatigue behavior of additive manufacturing aluminum alloys. It can provide reference for improving the process parameters of SLM technology.

The main aim of this study is to determine the fracture toughness and accordingly to predict the fracture initiation, crack propagation and mode of crack extension accurately in polypropylene subsea pipes subjected to internal pressure.

Tensile test was performed following the ISO 527–1 standard. An elastic-plastic constitutive model was developed based on the tensile test results, and it is implemented in the FEA model to describe the constitutive behaviour of the polypropylene material. Three-point bend tests with linear-elastic fracture mechanics (LEFM) approach were conducted following ISO-13586 standard, from which the average fracture toughness of the polypropylene pipe material in crack-opening mode was found as KIc = 3.3 MPa√m. A numerical model of the experiments is developed based on the extended finite element method (XFEM), which showed markedly good agreement with the experimental results.

The validated XFEM modelling approach is utilised to illustrate its capabilities in predicting fracture initiation and crack propagation in a polypropylene subsea pipe subjected to an internal pressure containing a semi-elliptical surface crack, which agrees well with existing analytical solutions. The XFEM model is capable of predicting the crack initiation and propagation in the polypropylene pipe up to the event of leakage.

The methodology proposed herein can be utilised to assess the structural integrity and resistance to fracture of subsea plastic pipes subjected to operational loads (e.g. internal pressure).

Integrity assessment is used to ensure reliability operation of a pressurized equipment containing defects. Based on data of cylindrical shell dimensions, operation conditions, material properties and crack dimensions, an assessment can be carried out, using either Level 1, Level 2 or Level 3 procedure. Assessment using Level 3 procedure within the code requires a finite element simulation in order to generate both the evaluation point and the failure assessment diagram (FAD) that serves as the acceptance criteria. The purpose of this paper is to provide the numerical data which are used for integrity assessment of a pressure vessel containing crack. Here, a parametric study has been carried out to generate such result for the cases of longitudinal crack defect in a cylindrical shell for a number of common cases, in terms of thickness-to-radius ratio, crack size ratio and crack aspect ratio.

The evaluation of stress intensity factor is determined through J-integral parameter found using a finite element analysis with a specially meshed strategy incorporating the crack. A comparison is made against stress intensity factor provided by the code.

A good agreement is obtained with percent error of 2.13 percent for low aspect ratio crack, and 0.57 percent for high aspect ratio crack. Furthermore, a study has been carried out using the methodology for 160 cases, covering both cases already available in the code and other cases of crack in cylindrical shells. The result can be used as a complement to the existing tabular data available in the code for Level 2 assessment, to be used for integrity analysis of damaged cylindrical shells based on the FAD criteria.

The result can be used as a complement to the existing tabular data available in the API 579 code for Level 2 assessment, to be used for integrity analysis of damaged cylindrical shells based on the FAD criteria. New equations were generated based on finite element analysis and can be used for Level 3 assessment of the code.

There is a reliability concern in the larger plastic surface mounting packages which can exhibit cracks from internal stresses during soldering. A lot of ad hoc information has been given to users of such packages about the origins of the problem and its alleviation. The phenomenon is the result of a combination of moisture absorbed in the plastic and the thermal stresses caused by the different expansions of the metal leadframe and the plastic. The work reported here gives quantitative data regarding the amount of moisture absorption critical to cracking, the range of baking procedures available to reduce this moisture below the critical level, and the acceptable floor life after baking for a wide range of storage temperatures and humidities.

This research paper adopts the fundamental tenets of advanced technologies in industry 4.0 to monitor the structural health of concrete beam members using cost-effective non-destructive technologies. In so doing, the work illustrates how a coalescence of low-cost digital technologies can seamlessly integrate to solve practical construction problems.

A mixed philosophies epistemological design is adopted to implement the empirical quantitative analysis of “real-time” data collected via sensor-based technologies streamed through a Raspberry Pi and uploaded onto a cloud-based system. Data was analysed using a hybrid approach that combined both vibration-characteristic-based method and linear variable differential transducers (LVDT).

The research utilises a novel digital research approach for accurately detecting and recording the localisation of structural cracks in concrete beams. This non-destructive low-cost approach was shown to perform with a high degree of accuracy and precision, as verified by the LVDT measurements. This research is testament to the fact that as technological advancements progress at an exponential rate, the cost of implementation continues to reduce to produce higher-accuracy “mass-market” solutions for industry practitioners.

Accurate structural health monitoring of concrete structures necessitates expensive equipment, complex signal processing and skilled operator. The concrete industry is in dire need of a simple but reliable technique that can reduce the testing time, cost and complexity of maintenance of structures. This was the first experiment of its kind that seeks to develop an unconventional approach to solve the maintenance problem associated with concrete structures. This study merges industry 4.0 digital technologies with a novel low-cost and automated hybrid analysis for real-time structural health monitoring of concrete beams by fusing several multidisciplinary approaches into one integral technological configuration.

A number of local authority‐built properties in the Aberdeen area were found to display evidence of horizontal cracking. An investigation carried out on one of these properties suggested that this damage resulted from sulphate attack of the mortar joints and it was assumed that this was the cause of damage in similar properties at the same location. However, this paper argues that wall‐tie corrosion is a more probable cause of the damage evident in these properties. It is suggested that the only effective and reliable method to establish an incidence of cavity wall‐tie corrosion is to carry out a direct inspection through the removal of a sample of ties.

Additive manufacturing (AM) studies on Inconel 718 (IN718) have focused on exploring its tensile and fatigue response. As IN718 is used in the propulsion and energy sector, the impact of shearing is also critical to ensuring the durability of these components. As such, this study aims to explore the relation between build orientation on the shear cyclic response of direct metal laser sintered (DMLS) IN718.

IN718 torsion specimens were manufactured along six build orientations: (100)-X, (010)-Y, (001)-Z, (110)-XY45, (101)-XZ45 and (011)-YZ45, using the DMLS process. Torsional fatigue testing was performed on as-built specimens, from which fracture behavior, surface roughness, softening/hardening response and monotonic/cyclic shear torsional properties were assessed.

DMLS IN718 was found to exhibit transversely isotropic behavior. In terms of shear stress range and shear modulus, Z > (X, XY45, Y) > (XZ45, YZ45). Specimens cyclically hardened to stabilization and softened to fracture. In terms of torsional fatigue fracture response, the Z, XZ45 and YZ45 specimens exhibited crack initiation and propagation from internal defects, whereas cracks were found to initiate at the surface and propagate between and through build layers for the X, Y and XY45 specimens.

This study reports the torsional cyclic response and shear moduli exhibited by as-built DMLS IN718 manufactured along varying build orientations. The findings are applicable for researchers because of the wide use of IN718 in the gas turbine industry, and the current trend to replace conventional manufacturing with AM.

This paper aims to use an imidazole-based n-ionic Gemini surfactant derived from palm oil to inhibit the sulfide stress corrosion cracking of a supermartensitic stainless steel.

The slow strain rate testing technique, hydrogen permeation tests and potentiodynamic polarization curves have been used.

Addition of the inhibitor below the critical micelle concentration (CMC) decreased the corrosion current density (i_corr), but not enough to avoid embrittlement due to the entry of hydrogen into the steel. Instead, the addition of the inhibitor close to the CMC decreased the i_corr, suppressed the entry of hydrogen and inhibited the sulfide stress cracking of steel. Finally, the addition of inhibitor above the CMC led to a slight increase of i_corr and promoted localized corrosion, however, the sulfide stress cracking of steel was inhibited.

A green sulfide stress corrosion cracking inhibitor of a supermartensitic stainless steel has been obtained.

Since the most of structures and structural components suffers from cyclic loadings, the study on the fatigue failure due to the crack growth has a great importance. The purpose of this paper is to present a three-dimensional fatigue crack growth simulation of embedded cracks using s-version finite element method (SFEM). Using the numerical results, the validity of the fitness-for-service (FFS) code evaluation method is verified.

In this paper, three-dimensional fatigue crack propagation analysis of embedded cracks is performed using the SFEM. SFEM is a numerical analysis method in which the shape of the structure is represented by a global mesh, and cracks are modeled by local meshes independently. The independent global and local meshes are superimposed to obtain the displacement solution of the problem simultaneously.

The fatigue crack growth of arbitrary shape of cracks is slow compared to that of the simplified circular crack and the crack approximated based on the FFS code of the Japan Society of Mechanical Engineers (JSME). The results tell us that the FFS code of JSME can provide a conservative evaluation of the fatigue crack growth and the residual life time.

This paper presents a three-dimensional fatigue crack growth simulation of embedded cracks using SFEM. Using this method, it is possible to apply mixed mode loads to complex shaped cracks that are closer to realistic conditions.