The rapid prototyping has been developed from the 1980s to produce models and prototypes until the technologies evolution today. Nowadays, these technologies have other names such as 3D printing or additive manufacturing, and so forth, but they all have the same origins from rapid prototyping. The design and manufacturing process stood the same until new requirements such as a better integration on production line, a largest series of manufacturing or the reduce weight of products due to heavy costs of machines and materials. The ability to produce complex geometries allows proposing of design and manufacturing solutions in the industrial field in order to be ever more effective. The additive manufacturing (AM) technology develops rapidly with news solutions and markets which sometimes need to demonstrate their reliability. The community needs to survey some evolutions such as the new exchange format, the faster 3D printing systems, the advanced numerical simulation or the emergence of new use. This review is addressed to persons who wish have a global view on the AM and improve their understanding. We propose to review the different AM technologies and the new trends to get a global overview through the engineering and manufacturing process. This article describes the engineering and manufacturing cycle with the 3D model management and the most recent technologies from the evolution of additive manufacturing. Finally, the use of AM resulted in new trends that are exposed below with the description of some new economic activities.
Additive Manufacturing or 3D Printing has a great potential to develop significant advances in materials, printers’ technology, and processes. Thus, the layer by layer manufacturing has existed for three decades and new developments recently appeared in smart materials. Laboratories discovered ways to design and manufacture advanced structured materials and responsive materials used in multi-functional and high-performance products. The current research and development efforts will have an impact on the traditional design and manufacturing process. 4D Printing announces a major modification in the product design and manufacturing process from static structures to dynamic structures like Shape Memory Material (SMM) with integrated functionalities. This article presents a review of smart materials based on a classification of advanced structured materials and responsive materials before beginning a description of current applications. The use of multi-materials and the study of predictive models to simulate the responsive materials behaviour accelerate the smart materials development.
23 December 2017 in International Journal of Fracture
In this paper, a numerical method is proposed to simulate the mechanical behavior of a new polymeric pre-structured material manufactured by fused filament fabrication (FFF), where the filaments are oriented along the principal stress directions. The model implements optimized filament orientations, obtained from the G code by assigning materials references in mesh elements. The Gauss points are later configured with the physical behavior while considering a homogeneous solid structure. The objective of this study is to identify the elastoplastic behavior. Therefore, tensile tests were conducted with different filament orientations. The results show that using appropriate material constants is efficient in describing the built anisotropy and incorporating the air gap volume fraction. The suggested method is proved very efficient in implementing multiplex G code orientations. The elastic behavior of the pre-structured material is quasi-isotropic. However, the anisotropy was observed at the yield point and the ultimate stress. Using the Hill criterion coupled with an experimental tabular law of the plastic flow turns out to be suitable for predicting the response of various specimens.
Purpose: The purpose of this paper is the application and the improvement of a previous method based on an acrylonitrile butadiene styrene thread deposition in fused deposition modeling. To gain up to 20 per cent of mechanical strength in comparison with a classical deposition, this method suggests a smart threads deposition in the principal stresses direction. Design/methodology/approach: In this work, the authors use single edge notched bend specimens with mixed mode I+II loading cases to study the influence of the thread deposition on the fracture toughness of the specimens. For this purpose, finite elements simulations have been used to evaluate the fracture toughness of the specimens through the calculation of the J integral. The study presents a method to compare the optimized and classical specimens and also to gather data and suggest a numerical model for this optimized deposition. For this reason, tensile tests are carried out to characterize the mechanical behavior of the printed samples with respect to the raster angle. Extra attention has been paid to 45 per cent samples behavior that shows a pronounced plasticity before the fracture. This interprets partially the improvement in the fracture behavior of the single edge notched bend samples. Findings: The results show an enhancement through this optimization which leads to an increase of the maximal force in fracture up to 20 per cent and the fracture toughness of the specimens with stress intensity factors KI and KII increases about 30 per cent. Originality/value: Additive manufacturing is increasingly gaining importance not only in prototyping but also in industrial production. For this reason, the characterization and the optimization of these technologies and their materials are fundamental. An adaptive deposition through a smart material based on specific mechanical behaviors would be an advance.