Building Geometry as a Variable in Energy, Comfort, and Environmental Design Optimization—A Review from the Perspective of Architects

Due to negative environmental impacts caused by the building industry, sustainable buildings have recently become one of the most investigated fields in research. As the design technique itself is mainly responsible for building performance, building energy design optimization is of particular interest. Several studies concentrate on systems, operation, and control optimization, complemented by passive strategies, specifically related to the envelope. In building physics, different architectural considerations, in particular, the building’s shape, are essential variables, as they greatly influence the performance of a building. Most scientific work that takes into consideration building geometry explores spaces without any energy optimization or calculates optimization processes of a few basic variables of simplified space geometries. Review studies mainly discuss the historic development of optimization algorithms, building domains, and the algorithm-system and software framework performance with coupling issues. By providing a systemized clustering of different levels of shape integration intensities, space creation principals, and algorithms, this review explores the current status of sustainability related shape optimization. The review proves that geometry design variable modifications and, specifically, shape generation techniques offer promising optimization potential; however, the findings also indicate that building shape optimization is still in its infancy.

Development and testing of an additively manufactured lattice for DEMO limiters

In the conceptual design of EU-DEMO, damage to plasma-facing components under disruption events is planned to be mitigated by specific sacrificial limiter components. A new limiter concept has been proposed using lattice structures fabricated with tungsten powder by additive manufacturing techniques. The major potential benefits of using a lattice structure for limiters are the possibility to customise the thermal conductivity and structural compliance of the structure to manage temperatures and stress within material limits and lower sensitivity to crack propagation. This paper presents the results of the first investigations into the production, characterisation, and high heat flux testing of the lattices to assess their suitability for DEMO limiters. First stage prototypes have been manufactured from tungsten and tungsten tantalum mixed powder with two distinct laser power bed fusion processes, namely pulsed laser and continuous laser with heated bed. The samples are characterised in terms of mass, volume, density, extent of microcracks and voids, level of un-melted or partially melted particulates, texture and grain size, as well as tantalum segregation when applicable. High transient (0.25ms) heat load testing, with hydrogen plasma of energy density up to ~3 MJm-2 was carried out at KIPT on the QSPA Kh-50. These tests have shown that the energy absorbed by latticed targets preheated at 500°C is close to that absorbed by solid tungsten, suggesting that they may be used for limiter applications with the added advantage of adjustment of the heat transfer and stiffness performance by geometry design or material properties.

Using discrete-element method hindcasting of screw pile performance for practical design

Screw piles have been used to support a variety of structures due to their ease of installation and high axial capacity. Recently, screw piles have been proposed as an alternative foundation solution for offshore renewable structures due to their quiet or silent installation. Due to their variable geometry, design and prediction of installation requirements and its effect on in-service capacity may be challenging. In this research study, the discrete-element method (DEM) is used to numerically recreate a series of onshore field tests. The aim of the study is to investigate the ability of DEM to be used as a practical design tool for the design and deployment of screw piles. In this case study, the effect of the geometric helix pitch on the installation torque and tensile capacity of screw piles installed into sand is investigated. DEM results show that the geometric pitch of a screw pile appears to have little effect on the installation torque. The results show that DEM has the potential to be used as a practical design procedure for complex foundation installation where the simulation needs to capture installation effects.

Geometry design and optimization of piston by using finite element method

The piston performance may be impacted by piston geometry, stress, temperature and deformation applied. Thus, the purpose of this study is to investigate the changes of piston performance with different piston head designs. Besides, the piston is optimized by using topology optimization to remove excessive material. The study was carried out by using the dimension of a piston based on the cylinder of a spark ignition engine. The four piston head designs are flat-top piston, bowl piston, square bowl piston and dome piston. All four piston designs were modelled by using Solidworks. Static Structural and Steady State Thermal Analysis in ANSYS Workbench were used to analyze the piston performance. The measured parameters are stress, deformation and temperature distribution. Next, optimization of piston was done by using topology optimization to identify non-essential parts that can be removed. The optimized piston design was analyzed. The findings for the original and optimized piston geometries were tabulated to make comparison. It is found that bowl piston has lower stress, deformation and temperature. The stress, deformation and temperature of optimized piston is lower than original piston. The mass of optimized piston is about 5 percent lesser than the original piston.

Needle-Free Jet Injectors’ Geometry Design and Drug Diffusion Process Analysis

In order to study the injection and diffusion process of the drug in the subcutaneous tissue of a needle-free jet injectors (NFJIs) in detail and understand the influence of different nozzle geometry on the diffusion process of the drug, in this paper, numerical simulations were performed to study the diffusion process of the drug in the subcutaneous tissue of NFJIs with cylindrical nozzle. On this basis, the differences of the drug diffusion process with different nozzle geometries were analyzed. The results show that the drug diffused in the shape of ellipsoid in the subcutaneous tissue. The penetration of the drug into the subcutaneous tissue is deeper under the condition of conical nozzle and conical cylindrical nozzle at the same time. However, it takes longer to spread to the interface between skin and subcutaneous tissue in reverse.

Irregular Symmetrical Object Designed By Using Lambda Miu B-Spline Degree Four

In Computer Aided Geometry Design (CAGD), B-splines curves are piecewise polynomial parametric curves that play an important role. CAGD involves the interpolation and approximation curves and surfaces. CAGD has been widely used which brings good impact of computers to industries in manufacturing. There are many improved methods in the B-spline curve such as extended cubic B-spline, trigonometric B-spline, quasi trigonometric B-spline, and λμ-B-spline. Each of the methods has its behaviour and advantage. In this paper, λμ-B-spline was used to be implemented in generating irregular symmetrical objects. λμ-B-spline has a shape parameter that can change the global shape by manipulating the value of the shape parameter. The bottle has been chosen as an irregular symmetrical object. The 2-dimensional symmetrical curves of Bottle design were formed by using λμ-B-spline degree 4. The curves designed are dependent on the shape parameter which can be adjusted. Then, the curves generated were revolved using the Sweep Surface method to form 3-dimensional objects. Every object has its volume and this research focused on the numerical method which was Simpson’s 3/8 to compute the volume. The volumes obtained were compared to the actual volume to determine the best shape parameter used. The results show that the λμ-B-spline curve with a shape parameter of 1 is the best shape parameter in designing symmetrical irregular objects with the desired volume.

Influence of Die Threading and Finishing Length in the Thread-Rolling Process Using Flat Dies: A Numerical Analysis

In this paper, a numerical analysis of the cold thread-rolling process using flat dies is presented as a function of the die geometry design. Five die geometries with different threading and finishing ratios were modelled to induce different screw deformation rates. An analytical method was proposed by the authors to design die geometries as a function of screw roll rotation. Screw geometry accuracy, induced stress, and die wear were selected to compare the tested geometries. The results showed that three screw rotations in the threading step were sufficient to guarantee good geometry accuracy. Moreover, the results highlighted that die wear is the most affected parameter among all the tested geometries. Finally, a new solution was proposed by the authors to obtain uniform wear and reduce the die length.

Inverted pyramid Azores - an eternal hybrid structure

Engineering structures are designed with observation of rules for structural performance under specific design loads, defined in the so-called structural codes. While dead loads are directly dependent from the selection of structural materials to a given structural function, live and accidental loads are often linked to the region where the structure must perform. In a complete opposition to engineering principles in Ancient Egypt, the inverted pyramid was designed to become a statement of how to bend gravitational laws, and what can be achieved by modern engineering, sill with intelligence to fulfill its function in a region where engineering structures are subjected to extreme live and accidental load regimes, e.g. high risk of earthquakes and high wind seasonal loads. A hybrid structural concept was specified, comprising lightweight structural wall elements anchored to a relatively heavyweight structural core. The suggested design concept fulfills the global equilibrium equation defined by architecture, and should become a structural example from a structural design perspective. As any other project involving non-comprehensive geometry, design and construction of the inverted pyramid is highly sensible to management options, which shall assure high precision manufacturing, and accurate control of its production.