Single camera photogrammetry for reverse engineering and fabrication of ancient and modern artifacts

Photogrammetry has been used for recording objects for well over one hundred and fifty years. Modern photogrammetry, or digital image capture, can be used with the aid of a single medium range digital single lens reflex (DSLR) camera, to transform two-dimensional images into three-dimensional CAD spatial representations, and together with the use of additive manufacturing or 3D Printing technology, geometric representations of original cultural, historic and geological artifacts can be fabricated in a process known as Reverse Engineering. Being able to replicate such objects is of great benefit in education; if the original object cannot be handled because it is too old or delicate, then replicas can give the handler a chance to experience the size, texture and weight of rare objects. Photogrammetry equipment is discussed, the objective being simplicity of execution for eventual realisation of physical products such as the artifacts discussed. As the processing power of computers has increased and become more widely available, and with the use of computer software programs it is now possible to digitally combine multi-view photographs, taken from 360° around the object, into 3D CAD representational virtual images. The resulting Data is then reprocessed, with a secondary computer program, to produce the STL file that the additive manufacturing machines can read, so as to produce replicated models of the originals. Three case studies are documented: the reproduction of a small modern clay sculpture; a 3000-year-old Egyptian artifact; and an Ammonite fossil, all successfully recreated, using additive manufacturing technology

Design and structural optimisation of a tractor mounted telescopic boom crane

In this research, an application algorithm, which can be used in computer-aided design/engineering (CAD/CAE) and structural optimisation-based design studies of agricultural machineries, is introduced. This developed algorithm has been put in practice in a case study for a tractor mounted telescopic boom crane. The algorithm consists of both numerical and experimental methods and it includes material testing, three-dimensional (3D) computer-aided design and finite-element method (FEM)-based analysis procedures, structural optimisation strategy, physical prototyping, physical testing and design validation procedures. Following the visual and physical validation procedures carried out in the case study, the crane’s physical prototype was manufactured and the optimised design was approved for ongoing production. The study provides a unique CAD/CAE and experimentally driven total design pathway for similar products, which contributes to further research into the utilisation of engineering simulation technology for agricultural machinery design, analysis and related manufacturing subjects

Fuzzy Logic Based Ventilation for Controlling Harmful Gases in Livestock Houses

There are many factors that influence the health and productivity of the animals in livestock production fields, including temperature, humidity, carbon dioxide (CO2), ammonia (NH3), hydrogen sulfide (H2S), physical activity and particulate matter. High NH3 concentrations reduce feed consumption and cause daily weight gain. At high concentrations, H2S causes respiratory problems and CO2, displace oxygen, which can cause suffocation or asphyxiation. Good air quality in livestock facilities can have an impact on the health and well-being of animals and humans. Air quality assessment is basically depend on strictly given limits without taking into account specific local conditions between harmful gases and other meteorological factors. The stated limitations may be eliminated. using controlling systems based on neural networks and fuzzy logic. This paper describes a fuzzy logic based ventilation algorithm, which can calculate different fan speeds under pre-defined boundary conditions, for removing harmful gases from the production environment. In the paper, a novel fuzzy logic model has been developed based on a Mamedani’s fuzzy method. The model has been built on MATLAB software. As the result, optimum fan speeds under pre-defined boundary conditions have been presented

Nonlinear FEM based high-speed shell shattering simulation for shelled edible agricultural products:Pecan fruit shattering

This paper introduces an advanced engineering simulation procedure for the nonlinear finite element method (FEM) based high-speed shattering case of shelled edible agricultural products. A high-speed impactor which is targeted at the Pecan fruit (kernel-in-shell) was considered in this case study. Physical compression tests were conducted on Pecan fruit specimens and experimental deformation characteristics were utilized to describe realistic material models in the FEM based engineering simulation. Subsequently, a reverse engineering approach was employed in the solid modeling stage and the Pecan shell shattering case under high-speed loading was simulated, considering the explicit dynamics approach. The effect of the high loading rate on the deformation characteristics of the Pecan fruit components was observed. Visual outputs from the simulation revealed the shattering behavior of the Pecan fruit components under defined boundary conditions. In addition to useful visual simulation outputs, time-dependant stress distributions on the Pecan fruit under high-speed loading rates were represented using graphs. Simulation results have revealed that maximum equivalent stress values were 7.1 (MPa), 5.1 (MPa), and 0.336 (MPa) for shell, packing material, and kernel, respectively. Maximum reaction force at impact was calculated as 996,000 (N). This work contributes to further research into the use of nonlinear numerical method based high-speed deformation simulation studies for shelled edible agricultural products

Reverse engineering approach for precise measurement of the physical attributes related to the geometric features of agricultural products

The characteristics related to the physical properties of agricultural products can be considered when designing and sizing machinery systems/equipment used in agricultural production. Agricultural products as biological/organic materials have several unique characteristics, which set them apart from conventional engineering materials such as steel and plastic based materials, in the context of inner structure and product geometry/shape. Agricultural materials have heterogeneous inner structures and irregular shapes cultured by nature. Most especially, the irregular shape of most agricultural products complicates their physical and engineering analysis. Therefore, precise description of the irregular product geometry/shape is significant for any related analyses used in both product quality evaluation and design of agricultural machinery systems. This study describes a reverse engineering application procedure for precise description of the physical attributes related to geometric features (size, shape, volume etc.) of the agricultural products under consideration. In the study, a three-dimensional (3D) laser scanner has been utilised and 3D digital model data of the selected sample agricultural product (Pecan) processed in the virtual environment through 3D scanner software and 3D parametric solid modelling design software has been collected. After 3D solid models were created, some of the physical attributes related to geometric features of the agricultural products were measured precisely and realistic virtual 3D computer aided design (CAD) data was provided for deeper rheological investigation such as structural deformation, fluid dynamics (flow) and heat transfer analyses of the products by means of computer aided engineering (CAE) techniques. Finally, a comparative deformation simulation case study was concluded. This study contributes to further research into the development of agricultural machinery and equipment through the utilisation of reverse engineering and CAD tools

Designing Digital Materials with Volumetric Gradients

Next-generation engineering designs could be digitally conceived as vast constellations of material dots in space and physically fabricated with advanced Additive Manufacturing (AM) technologies. AM is already transforming how we create physical objects across a wide range of manufacturing industries. However, recent advances in multi-material AM make it possible to envision a form of three-dimensional pointillism, whereby complex structures are designed and assembled on a micron-by-micron basis through the precise placement of different material “dots” within three-dimensional space. In line with traditional pointillism techniques, different compositions of many small dots would collectively give rise to higher-level properties such as colour and geometry, but also physical properties such as: topology, stiffness, flexibility, and transparency. This paper first describes exciting challenges and opportunities associated with designing multi-material objects as constellations of material dots, then outlines initial experiments which explore data-driven volumetric gradients to design and fabricate physical objects using advanced PolyJet technologies

Pressure Drop and Velocity Simulations in Non-Stochastic Structures - Filters Fabricated by Additive Manufacturing

This research utilises additive manufacturing technology to fabricate filter mesh designed with non-stochastic lattice structures. Disc filters with 1-layer, 2-layer and 3-layer thicknesses of repeated 1.8 mm lattice unit cell as the filter mesh are modelled in SolidWorks. Computational Fluid Dynamic (CFD) simulation using ANSYS CFX is performed at eight different flow rates (250-390 lit/min) and the results (pressure drop and velocity) are analysed. Simulations are also done for perforated plates with circular-shaped and square-shaped holes with the same aperture size and filter cut point for benchmarking purposes. The outcomes indicate that the pressure drop of the lattice filters is noticeably lower than the perforated plates. These findings show that several layers of lattice structure could be stacked together as filter mesh to increase filtration efficiency with minimal pressure drop and to create a more tortuous path for the fluid

A Short Review on 4D Printing

Additive Manufacturing can be described as a process to build 3D objects by adding layer-upon-layer of material, the material traditionally being plastics, metals or ceramics, however ‘smart’ materials are now in use. Nowadays, the term “3D Printing” has become a much-used synonym for additive manufacturing. The use of computing, 3D solid modeling applications, layering materials and machine equipment is common to majority of additive manufacturing technologies. Advancing from this 3D printing technology, is an emerging trend for what is being termed “4D printing”. 4D printing places dependency on smart materials, the functionality of additive manufacturing machines and in ingenious design processes. Although many developments have been made, limitations are still very much in existence, particularly with regards to function and application. The objective of this short review is to discuss the developments, challenges and outlook for 4D printing technology. The review revealed that 4D printing technology has application potential but further research work will be vital for the future success of 4D printing

Directing self-assembly to grow adaptive physical structures

Additive manufacturing technologies offer exciting opportunities to rethink the process of designing and fabricating physical structures. This paper outlines initial work that seeks to extend existing AM capabilities, creating physically adaptive structures by exploiting processes of self-assembling materials. The paper details an investigation of self-assembling structures that can respond to different conditions by adapting their physical properties over time. The process uses electrolysis of seawater to demonstrate a proof-of concept of tuneable material structures, via crystal growth. Results demonstrate an aggregation-based multi-material system that is sensitive to changing environmental conditions. Material properties of grown structures have been analysed and illustrate that different materials can be created from an abundant base material (seawater) by manipulating environmental conditions (i.e. electrical current). It is found that turbulence is a useful property within these kinds of systems and that the physical properties of cathode scaffold structures have a significant impact in controlling material properties and resolution

3D printed facial laser scans for the production of localised radiotherapy treatment masks

This study investigates the use of 3D printing for patients that require localised radiotherapy treatment to the face. The current process involves producing a lead mask in order to protect the healthy tissue from the effects of the radiotherapy. The mask is produced by applying a thermoplastic sheet to the patient’s face and allowing to set hard. This can then be used as a mould to create a plaster impression of the patient’s face. A sheet of lead is then hammered on to the plaster to create a bespoke fitted face mask. This process can be distressing for patients and can be problematic when the patient is required to remain motionless for a prolonged time while the thermoplastic sets. In this study, a 1:1 scale 3D print of a patient’s face was generated using a laser scanner. The lead was hammered directly on to the surface of the 3D print in order to create a bespoke fitted treatment mask. This eliminated the thermoplastic moulding stage and significantly reduced the time needed for the patient to be in clinic. The higher definition impression of the face resulted in a more accurate, better fitting treatment mask