Stability of 3D printing using a mixture of pea protein and alginate: Precision and application of additive layer manufacturing simulation approach for stress distribution

2021 ◽  
Vol 288 ◽  
pp. 110127 ◽  
Author(s):  
Timilehin Martins Oyinloye ◽  
Won Byong Yoon
2014 ◽  
Vol 96 (7) ◽  
pp. 230-231 ◽  
Author(s):  
Craig Gerrand

The convergence of digital technologies in imaging, surgical navigation and additive layer manufacturing has opened up new possibilities for surgeons in many fields. One of these is the reconstruction of major bone defects after the resection of primary bone tumours.


Author(s):  
Rohit Pandey ◽  
Sandeep Salodkar

Purpose of study: Additive manufacturing processes taking the basic information form computer-aided design (CAD) file to convert into the stereolithography (STL) data file. Today additive layer manufacturing processes are playing a very vital role in manufacturing parts with high rate of effectiveness and accuracy. CAD software is approximated to sliced containing information of each layer by layer that is printed. The main purpose of the study is to discuss the scientific and technological challenges of additive layer manufacturing processes for making polymer components production through various technological parameters and problem-solving techniques of layer manufacturing processes. Main findings: Additive layer manufacturing is simply another name for 3D printing or rapid prototyping. As 3D printing has evolved as a technology, it has moved beyond prototyping and into the manufacturing space, with small runs of finished components now being produced by 3D printing machines around the world. Additive layer manufacturing (ALM) is the opposite of subtractive manufacturing, in which material is removed to reach the desired shape Methodology Used:  The continuous and increasing growth of additive layer manufacturing processes to discuss with different experimental behavior through simulations and graphical representations. In ALM, 3D parts are built up in successive layers of material under computer control. In its early days, 3D printing was used mainly for rapid prototyping, but it is now frequently used to make finished parts the automotive and aerospace sectors, amongst many others. The originality of study: At the present time, the technologies of additive manufacturing are not just using for making models with the plastics but using polymer materials. It is possible to make finished products developed with high accuracy and save a lot of time and there is the possibility of testing more models.


2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Ercan M. Dede ◽  
Shailesh N. Joshi ◽  
Feng Zhou

Topology optimization of an air-cooled heat sink considering heat conduction plus side-surface convection is presented. The optimization formulation is explained along with multiple design examples. A postprocessing procedure is described to synthesize manifold or “water-tight” solid model computer-aided design (CAD) geometry from three-dimensional (3D) point-cloud data extracted from the optimization result. Using this process, a heat sink is optimized for confined jet impingement air cooling. A prototype structure is fabricated out of AlSi12 using additive layer manufacturing (ALM). The heat transfer and fluid flow performance of the optimized heat sink are experimentally evaluated, and the results are compared with benchmark plate and pin-fin heat sink geometries that are conventionally machined out of aluminum and copper. In two separate test cases, the experimental results indicate that the optimized ALM heat sink design has a higher coefficient of performance (COP) relative to the benchmark heat sink designs.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuezong Wang ◽  
Jinghui Liu ◽  
Mengfei Guo ◽  
LiuQIan Wang

Purpose A three-dimensional (3D) printing error simulation approach is proposed to analyze the influence of tilted vertical beams on the 3D printing accuracy. The purpose of this study is to analyze the influence of such errors on printing accuracy and printing quality for delta-robot 3D printer. Design/methodology/approach First, the kinematic model of a delta-robot 3D printer with an ideal geometric structure is proposed by using vector analysis. Then, the normal kinematic model of a nonideal delta-robot 3D robot with tilted vertical beams is derived based on the above ideal kinematic model. Finally, a 3D printing error simulation approach is proposed to analyze the influence of tilted vertical beams on the 3D printing accuracy. Findings The results show that tilted vertical beams can indeed cause 3D printing errors and further influence the 3D printing quality of the final products and that the 3D printing errors of tilted vertical beams are related to the rotation angles of the tilted vertical beams. The larger the rotation angles of the tilted vertical beams are, the greater the geometric deformations of the printed structures. Originality/value Three vertical beams and six horizontal beams constitute the supporting parts of the frame of a delta-robot 3D printer. In this paper, the orientations of tilted vertical beams are shown to have a significant influence on 3D printing accuracy. However, the effect of tilted vertical beams on 3D printing accuracy is difficult to capture by instruments. To reveal the 3D printing error mechanisms under the condition of tilted vertical beams, the error generation mechanism and the quantitative influence of tilted vertical beams on 3D printing accuracy are studied by simulating the parallel motion mechanism of a delta-robot 3D printer with tilted vertical beams.


Author(s):  
Sagar H. Nikam ◽  
N. K. Jain

Prediction of residual stresses induced by any additive layer manufacturing process greatly helps in preventing thermal cracking and distortion formed in the substrate and deposition material. This paper presents the development of a model for the prediction of residual stresses using three-dimensional finite element simulation (3D-FES) and their experimental validation in a single-track and double-track deposition of Ti-6Al-4V powder on AISI 4130 substrate by the microplasma transferred arc (µ-PTA) powder deposition process. It involved 3D-FES of the temperature distribution and thermal cycles that were validated experimentally using three K-type thermocouples mounted along the deposition direction. Temperature distribution, thermal cycles, and residual stresses are predicted in terms of the µ-PTA process parameters and temperature-dependent properties of substrate and deposition materials. Influence of a number of deposition tracks on the residual stresses is also studied. Results reveal that (i) tensile residual stress is higher at the bonding between the deposition and substrate and attains a minimum value at the midpoint of a deposition track; (ii) maximum tensile residual stress occurs in the substrate material at its interface with deposition track. This primarily causes distortion and thermal cracks; (iii) maximum compressive residual stress occurs approximately at mid-height of the substrate material; and (iv) deposition of a subsequent track relieves tensile residual stress induced by the previously deposited track.


Author(s):  
Ershad Mortazavian ◽  
Zhiyong Wang ◽  
Hualiang Teng

The complicated steel wheel and rail interaction on curve causes side wear on rail head. Thus, the cost of maintenance for the track on curve is significantly higher than that for track on a tangent. The objective of this research is to develop 3D printing technology for repairing the side wear. In this paper, the study examines induced residual thermal stresses on a rail during the cooling down process after 3D printing procedure using the coupled finite volume and finite element method for thermal and mechanical analysis respectively. The interface of the railhead and additive materials should conserve high stresses to prevent any crack initiation. Otherwise, the additive layer would likely shear off the rail due to crack propagation at the rail/additive interface. In the numerical analysis, a cut of 75-lb ASCE (American Society of Civil Engineers) worn rail is used as a specimen, for which a three-dimensional model is developed. The applied residual stresses, as a result of temperature gradient and thermal expansion coefficient mismatch between additive and rail materials, are investigated. At the beginning, the worn rail is at room temperature while the additive part is at a high initial temperature. Then, additive materials start to flow thermal energy into the worn rail and the ambient. The thermal distribution results from thermal analysis are then employed as thermal loads in the mechanical analysis to determine the von-Mises stress distribution as the decisive component. Then, the effect of preheating on residual stress distribution is studied. In this way, the thermo-mechanical analysis is repeated with an increase in railhead’s initial temperature. In thermal analysis, the temperature contours at different time steps for both the non-preheated and preheated cases indicate that preheating presents remarkably lower temperature gradient between rail and additive part and also represents a more gradual cooling down process to allow enough time for thermal expansion mismatch alignment. In mechanical analysis, the transversal von-Mises stress distribution at rail/additive interface is developed for all cases for comparison purposes. It is shown that preheating is a key factor to significantly reduce residual stresses by about 40% at all points along transversal direction of interface.


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