scholarly journals Multiphysics modelling of the mechanical properties in polymers obtained via photo-induced polymerization

2021 ◽  
Author(s):  
Roberto Brighenti ◽  
Mattia Pancrazio Cosma ◽  
Liviu Marsavina ◽  
Andrea Spagnoli ◽  
Michele Terzano
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Statistical Approach ◽  
Raw Material ◽  
Advanced Technology ◽  
Degree Of Cure ◽  
Monomer Solution ◽  
Multiphysics Modelling ◽  
Light Diffusion ◽  
Kinetics Of

AbstractPhotopolymerization is an advanced technology to trigger free radical polymerization in a liquid monomer solution through light-induced curing, during which mechanical properties of the material are significantly transformed. Widely used in additive manufacturing, parts fabricated with this technique display precisions up to the nanoscale; however, the performance of final components is not only affected by the raw material but also by the specific setup employed during the printing process. In this paper, we develop a multiphysics model to predict the mechanical properties of the photo-cured components, by taking into account the process parameters involved in the considered additive manufacturing technology. In the approach proposed, the main chemical, physical, and mechanical aspects of photopolymerization are modelled and implemented in a finite element framework. Specifically, the kinetics of light diffusion from a moving source and chain formation in the liquid monomer is coupled to a statistical approach to describe the mechanical properties as a function of the degree of cure. Several parametric examples are provided, in order to quantify the effects of the printing settings on the spatial distribution of the final properties in the component. The proposed approach provides a tool to predict the mechanical features of additively manufactured parts, which designers can adopt to optimize the desired characteristics of the products.

Quasi-Static Characterization of Polyamide-Based Discontinuous CFRP Manufactured by Additive Manufacturing and Injection Molding

2019 ◽  
Vol 809 ◽  
pp. 386-391 ◽  
Author(s):  
Patrick Striemann ◽  
Daniel Hülsbusch ◽  
Michael Niedermeier ◽  
Frank Walther
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Injection Molding ◽  
Mechanical Characterization ◽  
Length Distribution ◽  
Deep Understanding ◽  
Raw Material ◽  
Void Content ◽  
Fused Deposition ◽  
Printing Direction

Generating serial components via additive manufacturing (AM) a deep understanding of process-related characteristics is necessary. The extrusion-based AM called fused layer manufacturing (FLM), also known as fused deposition modeling (FDM™) or fused filament fabrication (FFF) is an AM process for producing serial components. Improving mechanical properties of AM parts is done by adding fibers in the raw material to reinforce the polymer. The study aims to create a more detailed comprehension of FLM and process-related characteristics with their influence on the composite.Thereby, a short carbon fiber-reinforced polyamide (CarbonX™ Nylon, 3DXTECH, USA) with 12.5 wt.‑% fiber content, 7 μm fiber diameter, and 150 to 400 µm fiber length distribution was investigated. To separate process-related characteristics of FLM, reference specimens were fabricated via injection molding (IM) with single-batch material. For the mechanical characterization, quasi-static tensile tests were carried out in accordance to DIN 527‑2. Quality assessment including void content and void distribution was performed via micro-computed tomography (CT).The mechanical characterization clarifies effects on mechanical properties depending on process-related characteristics of FLM. CT scans show higher void contents of FLM specimens compared to IM specimens and void orientation dependent on printing direction. FLM shows process-related characteristics which generally strengthen mechanical properties of polymers. Nevertheless, tensile strength of FLM specimens decrease by more than 28% compared to quasi-homogenous IM specimens.

Recycling of PA-12 in Additive Manufacturing and the Improvement of its Mechanical Properties

2016 ◽  
Vol 674 ◽  
pp. 9-14 ◽  
Author(s):  
Piret Mägi ◽  
Andres Krumme ◽  
Meelis Pohlak
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Raw Material ◽  
Positive Finding ◽  
Polyamide 12 ◽  
Fused Deposition ◽  
Micro Injection Moulding ◽  
Moulding Machine

This study explores possible ways to make Additive Manufacturing (AM) a cradle-to-cradle process, that is, use the leftover from one process as the raw material for another process. The main goal of this study is to develop a set of new polymeric blends with innovative properties, suitable for using in 3-D printing of prosthetic limbs using Fused Deposition Modeling (FDM) technology. Sustainable acting is achieved by reusing polymeric material left over from Selective Laser Sintering (SLS) processes for making raw material for FDM processes. Test specimens of polyamide 12 (PA-12) in its virgin form and used- , un-sintered form alongside specimens of used PA blended with TPU, aramid, or graphite, were produced in a micro-injection moulding machine and then tested for their mechanical properties. This paper provides information about the differences in mechanical characteristics of these different material blends. An unexpected but positive finding was that the differences between virgin and recycled PA-12 are insignificant. The aforementioned additives influenced PA-12 by producing specimens that responded with predictable characteristics which is a significant accomplishment as it lays the groundwork for the next stages of the project.

Prediction of Mechanical Properties of Direct Metal Laser Sintered 15-5PH Steel Parts Using Bayesian Inference: A Preliminary Study

2019 ◽  
Author(s):  
Ala Qattawi ◽  
Durul Ulutan ◽  
Ala’aldin Alafaghani
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Statistical Approach ◽  
Processing Parameters ◽  
Training Dataset ◽  
Layer By Layer ◽  
Probabilistic Prediction ◽  
Testing Data ◽  
Preliminary Study ◽  
Prediction Of Mechanical Properties

Abstract Direct Metal Laser Sintering (DMLS) is an additive manufacturing process where metal parts are created layer by layer. Mechanical properties of the final product can vary significantly based on processing parameters. In traditional processes, such effects of processing parameters on mechanical properties are well-established. However, additive manufacturing methods are relatively new, which means there is less consensus, if at all, on how processing parameters affect mechanical properties of the final product. This study is a preliminary effort toward understanding the effects of processing parameters on mechanical properties of the metal. Processing parameters studied were the fabrication direction and temperature. Mechanical properties that were studied were the yield and tensile strength of the built material. 15-5PH stainless steel parts were DMLS fabricated with varying temperatures and directions for this purpose and their mechanical properties were measured. Then, a statistical approach was followed in order to generate a probabilistic prediction model. In this approach, Gibbs sampling was used to randomly sample from population of coefficients, Metropolis algorithm was used for decision-making purposes based on performance of different coefficient sets, and an empirical model was hypothesized. Then, the model was trained using a training dataset, and the cloud of coefficient sets for the hypothesized equation were obtained. Using these coefficient sets, the probable normal distribution of other test conditions was predicted and verified using testing data. It was shown that all measurements were well within the confidence interval of predictions, with a maximum difference of 4% between mean predictions and measurements. It was also observed that with a coefficient of variation smaller than 18%, spread of predictions was low enough to suggest that predictions were precise as well as their accuracy.

Build Orientation Influence on some Mechanical Properties of 3D-Printed Polyamide Specimens

2019 ◽  
Vol 34 ◽  
pp. 3-9
Author(s):  
Alexandra Nitoi ◽  
Mihai Alin Pop ◽  
Ting Ting Peng ◽  
Tibor Bedő ◽  
Sorin Ion Munteanu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Raw Material ◽  
Processing Technologies ◽  
Build Orientation ◽  
Hardness Tests ◽  
Metallic Parts ◽  
Polyamide Powder

Additive manufacturing [AM] is a type of production technology characterized by the additive nature of stacking and unifying individual layers, with the main advantage that parts with complex geometries can easily be obtained, compared to conventional production methods. Due to its working principle, i.e. stacking layers, obtained by melting and solidification, the mechanical characteristics of the built part might be influenced by the build orientation chosen for the specific part. The mechanical behavior, cyclic deformation and fatigue behaviors of additively manufactured metallic parts as compared to their counterparts obtained by conventional processing technologies was reported to be highly dependent on the build orientation. The aim of this study was to assess whether the build orientation will have an impact on the mechanical properties of parts built by Selective Laser Sintering, using polyamide powder as raw material. Samples were built at various inclination degrees, and were further tested in terms of bending, compressive, impact and hardness tests. It was observed that the build orientation has a significant effect on the mechanical properties of parts additively manufactured from polyamide, compared to the behavior presented on the technical sheet of the material, provided by the manufacturer. Keywords: additive manufacturing, mechanical properties, build orientation, Selective Laser Sintering

Additive Manufacturing of Aluminum Alloys

2019 ◽  
Author(s):  
Sriram Praneeth Isanaka ◽  
Sreekar Karnati ◽  
Frank Liou
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Aluminum Alloys ◽  
Raw Material ◽  
Additive Manufacture ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Grain Structures ◽  
Direct Energy ◽  
Am Processes

Successful additive manufacturing (AM) of aluminum alloys has been demonstrated using a number of processes, which is the focus of this article. Utilization of some aluminum alloys with relatively low reflectivity coupled with process optimization to achieve high retained energy densities enabled the successful deposition of aluminum–silicon alloys that were previously manufactured exclusively using casting processes. The design flexibility of AM processes coupled to the ability to direct energy and material to specific spatial locations has also been used to demonstrate the ability to join dissimilar aluminum alloys, with applicability toward functional grading and repair. Researchers have shown that the additively manufactured alloys exhibit comparable and, in cases, improved mechanical properties to their conventional counterparts with highly refined grain structures. Elaborate investigations into their microstructures to determine the causality of the mechanical properties are also discussed in detail. Understanding the relationship between these desired high retained energy densities and the factors favoring them, including the alloy composition, input energy, and the deposition speed and volume, plays a pivotal role toward successful additive manufacture. With further process parameter optimization and the development of raw material supply chains that can create and tailor alloys based on need, the applicability of these AM processes can be adapted to many more aluminum alloys and can be tailored to serve a wide range of industries.

Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
Author(s):  
Laurent Royer ◽  
Stéphane Mathieu ◽  
Christophe Liebaut ◽  
Pierre Steinmetz
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Molten Glass ◽  
Energy Production ◽  
Creep Properties ◽  
Refractory Alloys ◽  
Industrial Use ◽  
Kinetics Of ◽  
Selection Of

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.

Control of humping phenomenon and analyzing mechanical properties of Al–Si wire-arc additive manufacturing fabricated samples using cold metal transfer process

2021 ◽  
pp. 095440622199840
Author(s):  
Yashwant Koli ◽  
N Yuvaraj ◽  
Aravindan Sivanandam ◽  
Vipin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Heat Input ◽  
Large Scale ◽  
High Deposition Rate ◽  
Bead Geometry ◽  
Layer By Layer ◽  
Cold Metal Transfer ◽  
Geometrical Shapes ◽  
Wire Arc Additive Manufacturing

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

scholarly journals Development of a 3D Printable and Highly Stretchable Ternary Organic-Inorganic Nanocomposite Hydrogel

2021 ◽  
Author(s):  
Chen Hu ◽  
Malik Haider ◽  
Lukas Hahn ◽  
Mengshi Yang ◽  
Robert Luxenhofer
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Nanocomposite Hydrogel ◽  
Highly Stretchable ◽  
Manufacturing Techniques ◽  
Advanced Applications

Hydrogels that can be processed with additive manufacturing techniques and concomitantly possess favorable mechanical properties are interesting for many advanced applications. However, the development of novel ink materials with high...

Sign in / Sign up

Export Citation Format

Share Document