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In this work, the cohesive zone model (CZM) developed by some of the authors to simulate the propagation of fatigue defects in two dimensions is extended in order to simulate the propagation of defects in 3D. The paper aims to discuss this issue.

The procedure has been implemented in the finite element (FE) solver (Abaqus) by programming the appropriate software-embedded subroutines. Part of the procedure is devoted to the calculation of the rate of energy release per unit, G, necessary to know the growth of the defect.

The model was tested on different joint geometries, with different load conditions (pure mode I, mode II pure, mixed mode I/II) and the results of the analysis were compared with analytical solutions or virtual crack closure technique (VCCT).

The possibility to simulate the growth of a crack without any re-meshing requirements and the relatively easy possibility to manipulate the constitutive law of the cohesive elements makes the CZM attractive also for the fatigue crack growth simulation. However, differently from VCCT, three-dimensional fatigue de-bonding/delamination with CZM is not yet state-of-art in FE softwares.

Adhesively bonded joints are gaining importance in the structural joining processes competing against welding and bolting processes. However, long-term behaviour of adhesively bonded joints is still an open question. Due to the increasing interest in adhesively bonded joints, mainly in the transports industry, there is a need to deep the knowledge about the fatigue behaviour of adhesive joints with metallic substrates allowing the development of reliable joints to resist cyclic loadings. The paper aims to discuss these issues.

An experimental research aiming at characterizing the fatigue behaviour of adhesively bonded aluminium substrates is presented in this paper, covering both fatigue crack propagation and global S-N behaviours. Double cantilever beam (DCB), end notch flexure (ENF) and double lap joints (DLJ) specimens built using the AA6061T651 substrate and epoxy adhesive were used to evaluate the pure modes I and II fatigue crack propagation rates and the S-N fatigue behaviours.

DCB and ENF specimens allowed the formulation of pure modes I and II fatigue crack propagation laws including the propagation thresholds. DLJs showed higher static shear strength than recommended by the manufacturer for aluminium substrates, but fatigue resistance of the DLJs was lower than suggested by the manufacturer. The fatigue damage process in the DLJs was dominated by a fatigue crack initiation process.

A consistent fatigue research on adhesively bonded aluminium substrates is presented covering in the same study aspects of fatigue crack propagation and fatigue crack initiation. Data reduction schemes involving both numerical and analytical procedures were followed. Proposed work constitutes a rigorous basis for future fatigue prediction models developments.

This paper aims to review the advances in additive manufactured (AM) scaffolds for bone tissue engineering (TE). A discussion on the state of the art and future trends of bone TE scaffolds have been done in terms of design, material and different AM technologies.

Different structural features and materials used for bone TE scaffolds are evaluated along with the discussion on the potential and limitations of different AM scaffolds. The latest research to improve the biocompatibility of the AM scaffolds is also discussed.

The discussion gives a clear understanding on the recent research trend in bone TE AM scaffolds.

The information available here would be useful for the researchers working on AM scaffolds to get a quick overview on the recent research trends and/or future direction to work on AM bone TE scaffolds.

This paper aims to provide a shimming method based on scanned data and finite element analysis (FEA) for a wing box assembly involving non-uniform gaps. The effort of the present work is to deal with gap compensation problem using hybrid shims composed of solid and liquid forms.

First, the assembly gaps of the mating components are calculated based on the scanned surfaces. The local gap region is extracted by the seed point and region growth algorithm from the scattered point cloud. Second, with the constraints of hole margin, gap space and shim specification, the optional shimming schemes are designed by the exhaustive searching method. Finally, the three-dimensional model of the real component is reconstructed based on the reverse engineering techniques, such as section lines and sweeping. Using FEA software ABAQUS, the stress distribution and damage status of the joints under tensile load are obtained for optimal scheme selection.

With the scanned mating surfaces, the non-uniform gaps are digitally evaluated with accurate measurement and good visualization. By filling the hybrid shims in the assembly gaps, the joint structures possess similar load capacity but stronger initial stiffness compared to the custom-shimmed structures.

This method has been tested with the interface data of a wing tip, and the results have shown good efficiency and automation of the shimming process.

The proposed method can decrease the manufacturing cost of shims, shorten the shimming process cycle and improve the assembly efficiency.

This paper aims to present a comparative analysis of noncompliance with planning laws in advanced-economy countries. Most research to date has focused on the widespread phenomenon of “informal” construction in developing countries. However, advanced-economy countries also encounter illegal development, though at different scales and attributes. Because planning law is at the foundation of land-use and urban policies, it is time that the “orphan” issue of noncompliance be adopted by more researchers to enable cross-national learning. The two OECD countries selected for in-depth analysis – Portugal and Israel – probably fall mid-way in the extent of noncompliance compared with the range among advanced-economy countries. Like most OECD countries, the selected countries have generally viable planning-law systems. Their experiences can thus offer lessons for many more countries. Recognizing the limitations of enforcement mechanisms as prevention, the paper focuses on how each of these countries responds to illegal development.

The method relies on two main sources: analysis of official documents – laws, policies and court decisions in both countries – and field interviews about practice. In both Portugal and Israel, the authors held face-to-face open interviews with lawyers and other professional staff at various government levels. The interviews focused on four issues: the effectiveness of the existing enforcement instruments, the urban consequences of illegal development, the law and policy regarding legalization and the existence of additional deterrent measures.

In both countries, there is a significant phenomenon of illegal development though it is somewhat less in Israel than in Portugal. In both countries, efforts to reduce the phenomenon have been partially effective even though in both, extensive demolition is not exercised. Neither country has adopted a general amnesty policy for existing noncompliance, so both resort to reliance on ex-post revision of statutory plans of granting of variances as a way of legalization. The shared tension between local authorities and national bodies indicates that not enough thought has gone into designing the compliance and enforcement systems. In Israel, a recent legislative amendment enables planning authorities, for the first time, to set their own priorities for enforcement and to distinguish between minor and major infringements. This approach is preferable to the Portuguese law, where there is still no distinction between minor and major infringements. By contrast, Portuguese law and policy are more effective in adopting financial or real-estate based deterrence measures which restrict sale or mortgaging of illegal properties.

There is very little research on noncompliance with planning controls in advanced-economy countries. There is even less research on the legal and institutional responses to this phenomenon. This paper pioneers in creating a framework for looking at alternative types of government responses to illegal construction. The paper is, to the authors’ best knowledge, the first to present a systematic cross-national comparative analysis and critique of such responses. The authors thus hope to expand the view of the possible legal and policy response strategies available to planning authorities in other advanced-economy countries. The comparative perspective will hopefully encourage, expansion of the research to more countries and contribute to the exchange of experiences between jurisdictions.

Material extrusion (MEX) 3D printers suffer from an intrinsic limitation of small size of the prints due to its restricted bed dimension. On the other hand, friction stir spot welding (FSSW) is gaining wide interest from automobile, airplane, off-road equipment manufacturers and even consumer electronics. This paper aims to explore the possibility of FSSW on Acrylonitrile Butadiene Styrene/Polylactic acid 3D-printed components to overcome the bed size limitation of MEX 3D printers.

Four different tool geometries (tapered cylindrical pin with/without concavity, pinless with/without concavity) were used to produce the joints. Three critical process parameters related to FSSW (tool rotational speed, plunge depth and dwell time) and two related to 3D printing (material combination and infill percentages) were investigated and optimized using the Taguchi L27 design of experiments. The influence of each welding parameter on the shear strength was evaluated by analysis of variance.

Results revealed that the infill percentage, a 3D printing parameter, had the maximum effect on the joint strength. The joints displayed pull nugget, cross nugget and substrate failure morphologies. The outcome resulted in the joint efficiency reaching up to 100.3%, better than that obtained by other competitive processes for 3D-printed thermoplastics. The results, when applied to weld a UAV wing, showed good strength and integrity. Further, grafting the joints with nylon micro-particles was also investigated, resulting in a detrimental effect on the strength.

To the best of the authors’ knowledge, this is the first study to demonstrate that the welding of dissimilar 3D-printed thermoplastics with/without microparticles is possible by FSSW, whilst the process parameters have a considerable consequence on the bond strength.

Adhesive bonding is critical to the effectiveness and structural integrity of 3D printed components. The purpose of this study is to investigate the effect of joint configuration on failure loads to improve the design and performance of single lap joints (SLJs) in 3D printed parts.

In this study, adherends were fabricated using material extrusion 3D printing technology with polyethylene terephthalate glycol (PETG). A toughened methacrylate adhesive was chosen to bond the SLJs after adherend printing. In this study, response surface methodology (RSM) was used to examine the effect of the independent variables of failure load, manufacturing time and mass on the dependent variable of joint configuration; adherend thickness (3.2, 4.0, 4.8, 5.6, 6.4, and 7.2 mm) and overlap lengths (12.7, 25.4, 38.1, and 50.8 mm) of 3D printed PETG SLJs.

The strength of the joints improved significantly with the increase in overlap length and adherend thickness, although the relationship was not linear. The maximum failure load occurred with a thickness of 7.2 mm and an overlap of 50.8 mm, whilst the minimum failure load was determined with a thickness of 3.2 mm and an overlap of 12.7 mm. The RSM findings show that the optimum failure load was achieved with an adherend thickness of 3.6 mm and an overlap length of 37.9 mm for SLJ.

This study provides insight into the optimum failure load for 3D printed SLJs, reducing SLJ production time and mass, producing lightweight structures due to the nature of 3D printing, and increasing the use of these parts in load-bearing applications.

This paper aims to design a vulnerability assessment model considering the multidimensional and systematic approach to disaster risk and vulnerability. This model serves to both risk mitigation and disaster preparedness phases of humanitarian logistics.

A survey of 27,218 households in Pueblo Rico and Dosquebradas was conducted to obtain information about disaster risk for landslides, floods and collapses. We adopted a cross entropy-based approach for the measure of disaster vulnerability (Kullback–Leibler divergence), and a maximum-entropy estimation for the reconstruction of risk a priori categorization (logistic regression). The capabilities approach of Sen supported theoretically our multidimensional assessment of disaster vulnerability.

Disaster vulnerability is shaped by economic, such as physical attributes of households, and health indicators, which are in specific morbidity indicators that seem to affect vulnerability outputs. Vulnerability is heterogeneous between communities/districts according to formal comparisons of Kullback–Leibler divergence. Nor social dimension, neither chronic illness indicators seem to shape vulnerability, at least for Pueblo Rico and Dosquebradas.

The results need a qualitative or case study validation at the community/district level.

We discuss how risk mitigation policies and disaster preparedness strategies can be driven by empirical results. For example, the type of stock to preposition can vary according to the disaster or the kind of alternative policies that can be formulated on the basis of the strong relationship between morbidity and disaster risk.

Entropy-based metrics are not widely used in humanitarian logistics literature, as well as empirical data-driven techniques.

The aim of the paper is to compare consumer acceptance, sensory analysis and volatile compounds of caiman meat with regard to surubí fish and chicken meat.

Caiman tail, chicken thigh and surubí meats' cuts were cooked in a pan with little oil and salt. The affective tests of acceptance (9-points hedonic scale) and preference ranking were evaluated by 80 consumers. Sensory analysis carried out by eight trained panelists described attributes' intensities on an unstructured linear scale (0–150 mm). Volatile compounds were analysed by solid-phase micro-extraction and gas chromatography/mass spectrometry GC–MS.

Caiman meat had good acceptance values of 6–7 (“like slightly” to “like moderately”), being similarly preferred to surubí but less than chicken. The ratings of bitterness, hardness, fibrous appearance, fibrous texture and cohesiveness were higher and raw colour, characteristic flavour and oiliness were lower in caiman's meat than in the others. Caiman meat had lower juiciness than chicken but similar to surubí. Caiman showed lower levels of aldehydes than chicken, lower level of hydrocarbons and higher levels of acids and esters than the other meats. Alcohols, mainly found in caiman and chicken meat, were positively associated to aroma acceptance. Hydrocarbons, mainly found in surubí meat, were positively associated with the characteristic flavour and negatively correlated with aroma acceptance. Volatile composition of meats was related to their sensory attributes and consumer acceptance.

Given that caiman meat showed similar acceptance and preference to that of surubí, it could be considered a good quality meat, helping promote current programmes of sustainable use of natural resources.