scholarly journals Micromechanical Characterisation of Ni/PU Hybrid Foams

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3746
Author(s):  
Martin Reis ◽  
Kristian König ◽  
Stefan Diebels ◽  
Anne Jung
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Tensile Tests ◽  
Experimental Investigations ◽  
Outer Diameter ◽  
Three Point Bending ◽  
Mechanical Characterisation ◽  
Energy Absorbers ◽  
Hybrid Foams ◽  
Aided Design

The computer-aided design of individual parts and the desire for weight reduction and material savings require further development of new hybrid materials. Ni/PU hybrid foams as a new hybrid material offer great potential for the production of components that are lightweight and yet can absorb large amounts of energy. The development of this structured material is at its beginning and mechanical characterisation on all scales is necessary. Experimental investigations on individual struts must be carried out on the micro scale to understand the structure-properties-relationship. Inspite of the challenges raising due to the complex geometry of the struts, tensile tests, three-point bending tests and micro sections are presented in this work. Due to the stiff Ni coating on the outer diameter of the struts, the resistance against bending is around five times as high as against tensile loading. The correlation between the behaviour of the struts and the macroscopic material behaviour validates the planned use of the foams as energy absorbers.

scholarly journals The Influence of Exposure Energy Density on Porosity and Microhardness of the SLM Additive Manufactured Elements

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2304 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Krzysztof Grzelak ◽  
Janusz Mierzyński
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Final Analysis ◽  
Machine Building ◽  
Layer By Layer ◽  
Laser Melting ◽  
Measurement Results ◽  
Computer Aided ◽  
Exposure Energy ◽  
Aided Design

Selective laser melting (SLM) is an additive manufacturing technique. It allows elements with very complex geometry to be produced using metallic powders. A geometry of manufacturing elements is based only on 3D computer-aided design (CAD) data. The metal powder is melted selectively layer by layer using an ytterbium laser. This paper contains the results of porosity and microhardness analysis made on specimens manufactured during a specially prepared process. Final analysis helped to discover connections between changing hatching distance, exposure speed and porosity. There were no significant differences in microhardness and porosity measurement results in the planes perpendicular and parallel to the machine building platform surface.

Powder Bed Fusion of Biomedical Co-Cr-Mo and Ti-6Al-4V Alloys: Microstructure and Mechanical Properties

2019 ◽  
Vol 1151 ◽  
pp. 3-7 ◽  
Author(s):  
Eleonora Santecchia ◽  
Paolo Mengucci ◽  
Andrea Gatto ◽  
Elena Bassoli ◽  
Lucia Denti ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
X Ray Diffraction ◽  
Powder Bed ◽  
Mechanical Parts ◽  
Aided Design ◽  
Microscopy Techniques ◽  
High Degree

Powder bed fusion (PBF) is an additive manufacturing technique, which allows to build complex functional mechanical parts layer-by-layer, starting from a computer-aided design (CAD) model. PBF is particularly attractive for biomedical applications, where a high degree of individualization is required. In this work, the microstructure of two biomedical alloys, namely Co-Cr-Mo and Ti-6Al-4V, were studied by X-ray diffraction and electron microscopy techniques. Hardness and tensile tests were performed on the sintered parts.

scholarly journals An Interactive Tool for Automatic Predimensioning and Numerical Modeling of Arch Dams

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
D. J. Vicente ◽  
J. San Mauro ◽  
F. Salazar ◽  
C. M. Baena
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Design Procedure ◽  
Software Tool ◽  
Gravity Dams ◽  
Detailed Model ◽  
Arch Dams ◽  
Double Curvature ◽  
Aided Design ◽  
Mass Volume

The construction of double-curvature arch dams is an attractive solution from an economic viewpoint due to the reduced volume of concrete necessary for their construction as compared to conventional gravity dams. Due to their complex geometry, many criteria have arisen for their design. However, the most widespread methods are based on recommendations of traditional technical documents without taking into account the possibilities of computer-aided design. In this paper, an innovative software tool to design FEM models of double-curvature arch dams is presented. Several capabilities are allowed: simplified geometry creation (interesting for academic purposes), preliminary geometrical design, high-detailed model construction, and stochastic calculation performance (introducing uncertainty associated with material properties and other parameters). This paper specially focuses on geometrical issues describing the functionalities of the tool and the fundamentals of the design procedure with regard to the following aspects: topography, reference cylinder, excavation depth, crown cantilever thickness and curvature, horizontal arch curvature, excavation and concrete mass volume, and additional elements such as joints or spillways. Examples of application on two Spanish dams are presented and the results obtained analyzed.

scholarly journals Development of Intertwined Infills to Improve Multi-Material Interfacial Bond Strength

2021 ◽  
pp. 1-10
Author(s):  
Irfan Mustafa ◽  
Tsz Ho Kwok
Keyword(s):  
Computer Aided Design ◽  
Material Design ◽  
Tensile Tests ◽  
Interfacial Bond Strength ◽  
Ongoing Research ◽  
Computer Aided ◽  
Cad Models ◽  
Multiple Materials ◽  
Aided Design ◽  
Material Information

Abstract Recently the availability of various materials and ongoing research in developing advanced systems for multi-material additive manufacturing (MMAM) have opened doors for innovation in functional products. One major concern of MMAM is the strength at the interface between materials. This paper hypothesizes overlapping and interlacing materials to enhance the bonding strength. To test this hypothesis, we need a computer-aided manufacturing (CAM) tool that can process the overlapped material regions. However, existing computational tools lack key multi-material design processing features and have certain limitations in making full use of the material information, which restricts the testing of our hypothesis. Therefore, this research also develops a new MMAM slicing framework that efficiently identifies the boundaries for materials to develop different advanced features. By modifying a ray tracing technology, we develop layered depth material images (LDMI) to process the material information from computer-aided design (CAD) models for slicing and process planning. Each sample point in the LDMI has associated material and geometric properties that are used to identify the multi-material regions. Based on the material information in each slice, interlocking joint (T-Joint) and interlacing infill are generated in the regions with multiple materials. Tensile tests have been performed to verify the enhancement of mechanical properties by the use of overlapping and interlacing materials.

scholarly journals Development of Intertwined Infills to Improve Multi-Material Interfacial Bond Strength

2021 ◽  
Author(s):  
Irfan Mustafa ◽  
Tsz-Ho Kwok
Keyword(s):  
Computer Aided Design ◽  
Material Design ◽  
Tensile Tests ◽  
Interfacial Bond Strength ◽  
Ongoing Research ◽  
Computer Aided ◽  
Cad Models ◽  
Multiple Materials ◽  
Aided Design ◽  
Material Information

Abstract Recently the availability of various materials and ongoing research in developing advanced systems for multi-material additive manufacturing (MMAM) have opened doors for innovation in functional products. One major concern of MMAM is the strength at the interface between materials. This paper hypothesizes overlapping and interlacing materials to enhance the bonding strength. To test this hypothesis, we need a computer-aided manufacturing (CAM) tool that can process the overlapped material regions. However, existing computational tools lack key multi-material design processing features and have certain limitations in making full use of the material information, which restricts the testing of our hypothesis. Therefore, this research also develops a new MMAM slicing framework that efficiently identifies the boundaries for materials to develop different advanced features. By modifying a ray tracing technology, we develop layered depth material images (LDMI) to process the material information from computer-aided design (CAD) models for slicing and process planning. Each sample point in the LDMI has associated material and geometric properties that are used to identify the multi-material regions. Based on the material information in each slice, interlocking joint (T-Joint) and interlacing infill are generated in the regions with multiple materials. Tensile tests have been performed to verify the enhancement of mechanical properties by the use of overlapping and interlacing materials.

Automatic Side-Cores Construction in Injection Plastic Mold Design for Free-Form NURBS Surface Models

2013 ◽  
Vol 275-277 ◽  
pp. 2635-2639 ◽  
Author(s):  
Nguyen Huu Quang ◽  
Alan C. Lin
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Automatic Generation ◽  
Free Form ◽  
Mold Design ◽  
Manufacturing Cost ◽  
Synthetic Approach ◽  
Nurbs Surface ◽  
Surface Models ◽  
Aided Design

In computer-aided design for moldings, automatic generation of side-cores is a crucial design task that has an influence on the entire mold structure and manufacturing cost. This paper proposes a synthetic approach for creating the side-cores of free-form NURBS surface models. Based on the geometric properties of entities, surfaces of undercut features which are molded for side-cores are identified. After determining the withdrawal directions for each group of undercut’s surface features, the number of side-cores is optimized. The heads and the bodies of side-cores are finally obtained through the combination of the Boolean operation and 3D oriented extrusion. The algorithm is efficiently for both protruded and indented portions of undercut features. A complex industrial part is used to demonstrate the performance and robustness of the proposed algorithm. Since the approach is generic in nature, it is easy to be applied to any complex geometry in 3D mold design.

Residual stress and quantitative phase mapping on complex geometries

2014 ◽  
Vol 29 (2) ◽  
pp. 176-185 ◽  
Author(s):  
Masoud Allahkarami ◽  
Jay C. Hanan
Keyword(s):  
Residual Stress ◽  
Computer Aided Design ◽  
Complex Geometry ◽  
Geometry Optimization ◽  
Curved Surfaces ◽  
Laser Alignment ◽  
Fine Mesh ◽  
Alignment System ◽  
Aided Design ◽  
Five Axis

As a consequence of substantial advances in computer-aided design and manufacturing technology, engineering parts are no longer restricted to combination of simple geometrical shapes. Implementing complex curved surfaces in engineering components in combination with finite-element geometry optimization has become a prevalent means of designing a part. Measuring residual stresses using X-ray diffraction (XRD) on complex curved surfaces requires further development of current measurement methods. Here we investigate how a laboratory XRD system equipped with a five-axis stage and two-dimensional detector can execute sin2ψ residual stress measurements on curved surfaces. Shadowing that blocks the diffracted beam to reach the detector was avoided using proper rotations and tilting of the sample. A standard video-laser alignment system commonly used to manually place the sample in the center of diffraction was used to also generate virtual maps of the sample's curved surfaces on a fine mesh grid. The geometry was then used for setting the required rotations and tilt angles. A set of diffraction frames collected using this method on a model zirconia dental ceramic, afforded the opportunity to superimpose phase and stresses on a complex geometry. This is a step forward for the XRD technology, and its usefulness applies to many different industries.

Computer Aided Design of Extrusion Dies for Complex Geometry Profiles

2012 ◽  
Vol 730-732 ◽  
pp. 495-500
Author(s):  
Nelson D. Gonçalves ◽  
Ângela M. Ribau ◽  
Olga S. Carneiro ◽  
João M. Nóbrega
Keyword(s):  
Cross Section ◽  
Computer Aided Design ◽  
Complex Geometry ◽  
Numerical Code ◽  
Extrusion Dies ◽  
Extrusion Die ◽  
Structured Meshes ◽  
Plastic Profile ◽  
Cross Section Profile ◽  
Aided Design

The inherent design freedom promoted by the employment of thermoplastic profiles is one of the major reasons for their attractiveness. Theoretically, thermoplastic profiles can be produced with any cross section suited for a specific application. The design of the corresponding extrusion dies usually employ a methodology based on experimental trial-and-error approaches, being highly dependent on the experience of the designer and highly demanding in terms of resources. These difficulties are obviously more evident when the plastic profile has a complex geometry. This research team is involved since the mid-nineties on the development of computational tools to aid the design of thermoplastic profile extrusion dies. Initially, the numerical code employed was based on structured meshes that limited its use to simple geometries. In this work, a numerical modelling code developed to work with unstructured meshes is described and employed in a case study involving the design of a extrusion die for the production of complex cross section profile. The results obtained show that the developed code can be a useful tool to aid the design of complex profile extrusion dies.

scholarly journals Computing Axes of Rotation for Setup Planning Using Visibility of Polyhedral Computer-Aided Design Models

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Ye Li ◽  
Matthew C. Frank
Keyword(s):  
Computer Aided Design ◽  
Feature Detection ◽  
Complex Geometry ◽  
Setup Planning ◽  
Polyhedral Model ◽  
Design Models ◽  
Axis Of Rotation ◽  
Computer Aided ◽  
Aided Design ◽  
Part Model

This paper presents a method for determining feasible axes of rotation for setup planning, based on the visibility of a polyhedral model. The intent of this work was to develop a feature-free approach to setup planning, with the specific focus on multi-axis machine setups. Visibility mapping can provide a quantitative evaluation of a surface, a feature or an entire part model; however, the next step is to use this information for process planning. In this paper, we present an approach of using a visibility map to evaluate axes of rotation that could be used in an indexer-type setup on a machine tool. Instead of using expensive and complicated multi-axis machining, it may be feasible to machine using multiple three-axis toolpaths if a single axis of rotation can be used to rotate the part through the minimum set of orientations. An algorithm is presented that is capable of processing visibility information from a polyhedral model; hence, the method is generic and does not require feature detection. As such, the work is applicable to a variety of applications; in particular for subtractive rapid prototyping where complex geometry may not contain recognizable features.

Strength and Deformability of Corroded Steel Plates Estimated by Replicated Specimens

2008 ◽  
Vol 24 (03) ◽  
pp. 161-167
Author(s):  
Yoichi Sumi
Keyword(s):  
Computer Aided Design ◽  
Tensile Tests ◽  
Steel Plates ◽  
Displacement Sensor ◽  
Bottom Plate ◽  
General Corrosion ◽  
Surface Geometry ◽  
Surface Data ◽  
Cad Cam ◽  
Aided Design

Strength and deformability of corroded steel plates are investigated using artificially pitted and replicated specimens processed by a computer-aided design/computeraided manufacturing (CAD-CAM) system that numerically controls a desktop milling machine to produce or replicate the surface geometry of a corroded surface. Periodic array of surface pits are made for self-similar specimens. Also, corroded surfaces are measured by scanning a plate by a laser displacement sensor, so that the surface data are stored to generate the input for the CAM system. As a typical example of plates with general corrosion, surface geometries of a sample specimen taken from the bottom plate of an aged tanker are reproduced, and the corresponding tensile tests are carried out. The reduction of the tensile strength is slight, while that of the elongation is significant. In order to examine the extent of the corroded surface, test specimens having different sample area but with the same thickness are tested, where the surface undulation is machined in the same scale. The test results show a slight dependence on the extent of the surface area.

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