Metal components with applications across a range of industrial sectors can be manufactured by selective laser melting (SLM). A particular strength of SLM is its ability to manufacture components incorporating periodic lattice structures not realisable by conventional manufacturing processes. This enables the production of advanced, functionally graded, components. However, for these designs to be successful, the relationships between lattice geometry and performance must be established. We do so here by examining the mechanical behaviour of uniform and graded density SLM Al-Si10-Mg lattices under quasistatic loading. As-built lattices underwent brittle collapse and non-ideal deformation behaviour. The application of a microstructure-altering thermal treatment drastically improved their behaviour and their capability for energy absorption. Heat-treated graded lattices exhibited progressive layer collapse and incremental strengthening. Graded and uniform structures absorbed almost the same amount of energy prior to densification, 6.3±0.26.3±0.2 MJ/m3 and 5.7±0.25.7±0.2 MJ/m3, respectively, but densification occurred at around 7% lower strain for the graded structures. Several characteristic properties of SLM aluminium lattices, including their effective elastic modulus and Gibson-Ashby coefficients, C1 and α, were determined; these can form the basis of new design methodologies for superior components in the future.

/pdf/a-mechanical-property-evaluation-of-graded-density-al-si10-2t3mb2ihpx.pdf

A mechanical property evaluation of graded density Al-Si10-Mg lattice structures manufactured by selective laser melting

Dynamic compressive behaviour of cellular materials: A review of phenomenon, mechanism and modelling

A review on functionally graded structures and materials for energy absorption

In recent years, significant progress has been made to ensure that process industries are among the safest workplaces in the world. However, with the increasing complexity of existing technologies and new problems brought about by emerging technologies, a strong need still exists to study the fundamentals of process safety and predict possible scenarios. This is attained by conducting the corresponding consequence modeling and risk assessments. As a result of the continuous advancement of Computational Fluid Dynamics (CFD) tools and exponentially increased computation capabilities along with better understandings of the underlying physics, CFD simulations have been applied widely in the areas of process safety and loss prevention to gain new insights, improve existing models, and assess new hazardous scenarios. In this review, 126 papers from 2010 to 2020 have been included in order to systematically categorize and summarize recent applications of CFD for fires, explosions, dispersions of flammable and toxic materials from accidental releases, incident investigations and reconstructions, and other areas of process safety. The advantages of CFD modeling are discussed and the future of CFD applications in this research area is outlined.

Recent application of Computational Fluid Dynamics (CFD) in process safety and loss prevention: A review

Dynamic response of slender multilayer sandwich beams with metal foam cores subjected to low-velocity impact

Vented Methane-air Explosion Overpressure Calculation—A simplified approach based on CFD

Robust data-driven model to study dispersion of vapor cloud in offshore facility

In this study, we present a newly developed correlation for the estimation of boundary overpressures in and around congested regions subjected to vapor gas explosions. The GAME correlation, which is based on the MERGE, EMERGE experimental programs, shows rather moderate correlation with computational fluid dynamics (CFD) results in homogeneously congested configurations, however, a greater level of inaccuracy is found when it comes to the combination of a number of realistic scenarios. The newly developed model (confinement specific correlation), which consists parameters of volume blockage ration, the density of the gas, the flame path distance, the confinement ratio and the laminar flame speed of the flammable gas is proposed as a non-dimensional alternative and it shows a closer correlation with detailed CFD simulation in general particularly for realistic geometries. A linear least square method is used to achieve the best fitting parameters by applying the validated commercial software FLACS. About 400 CFD cases with homogenous congestions are modeled using FLACS for the purpose of testing both the GAME correlation and the confinement specific correlation (CSC). In addition to those 400 CFD homogenous cases, around 700 realistic cases in ten different module scenarios of a Liquefied Natural Gas (LNG) train along with three simplified models are simulated to validate the CSC; it is found that the CSC is applicable to both realistic modules with irregular obstacles and homogenous artificial modules.

New correlation for vapor cloud explosion overpressure calculation at congested configurations

A state-of-the-art review of road tunnel subjected to blast loads

So far, the prediction of blast wave generated from the Boiling Liquid Expanding Vapour Explosion (BLEVE) has been already broadly investigated. However, only a few validations of these blast wave prediction models have been made, and some well-established methods are available to predict BLEVE overpressure in the open space only. This paper presents numerical study on the estimation of the near-field and far-field blast waves from BLEVEs. The scale effect is taken into account by conducting two different scale BLEVE simulations. The expansion of pressurized vapour and evaporation of liquid in BLEVE are both modelled by using CFD method. Two approaches are proposed to determine the initial pressure of BLEVE source. The vapour evaporation and liquid flashing are simulated separately in these two approaches. Satisfactory agreement between the CFD simulation results and experimental data is achieved. With the validated CFD model, the results predicted by the proposed approaches can be used to predict explosion loads for better assessment of explosion effects on structures.

Jingde Li

Papers

Vented Methane-air Explosion Overpressure Calculation—A simplified approach based on CFD

Robust data-driven model to study dispersion of vapor cloud in offshore facility

New correlation for vapor cloud explosion overpressure calculation at congested configurations

A state-of-the-art review of road tunnel subjected to blast loads

Numerical study of medium to large scale BLEVE for blast wave prediction