Post-doc, University of Michigan
Use multi-functional cementitious materials to 3D print infrastructure
Compared with contemporary concrete structure’s construction method, three-dimensional (3D) printing has great potential to improve the construction process by reducing the construction time, labor, cost, hazards, and impacts on environment; hence it is attracting increasing interests in construction industry. As an additive manufacturing approach, 3D printing facilitates diverse architectural and structural designs. Complex geometries that are difficult to construct through conventional construction processes can be built much more easily and economically using 3D printing. Furthermore, an existing design can be changed by properly modifying the computer-aided design model in a 3D printing procedure, without any need to customize formwork to fit the new design. This gives architectural and structural designers freedom to make each design unique and architecturally appealing, while simultaneously optimizing structural performance. My research is aimed to address fundamental technical challenges and bridge the knowledge gaps, thus advancing this emerging construction technique.
Abstract: In the present paper a new additive manufacturing processing route is introduced for ultra-high performance concrete. Interdisciplinary work involving materials science, computation, robotics, architecture and design resulted in the development of an innovative way of 3D printing cementitious materials. The 3D printing process involved is based on a FDM-like technique, in the sense that a material is deposited layer by layer through an extrusion printhead mounted on a 6-axis robotic arm. The mechanical properties of 3D printed materials are assessed. The proposed technology succeeds in solving many of the problems that can be found in the literature. Most notably, this process allows the production of 3D large-scale complex geometries, without the use of temporary supports, as opposed to 2.5D examples found in the literature for concrete 3D printing. Architectural cases of application are used as examples in order to demonstrate the potentialities of the technology. Two structural elements were produced and constitute some of the largest 3D printed concrete parts available until now. Multi-functionality was enabled for both structural elements by taking advantage of the complex geometry which can be achieved using our technology for large-scale additive manufacturing.
Pub.: 25 Mar '16, Pinned: 21 Aug '17
Abstract: Authors: Freek Bos ; Rob Wolfs ; Zeeshan Ahmed ; Theo Salet Article URL: http://www.tandfonline.com/doi/full/10.1080/17452759.2016.1209867?ai=z4&mi=3fqos0&af=R Citation: Virtual and Physical Prototyping Publication Date: 2016-08-03T02:58:59Z Journal: Virtual and Physical Prototyping
Pub.: 03 Aug '16, Pinned: 21 Aug '17
Abstract: A challenge for tissue engineering is producing three-dimensional (3D), vascularized cellular constructs of clinically relevant size, shape and structural integrity. We present an integrated tissue–organ printer (ITOP) that can fabricate stable, human-scale tissue constructs of any shape. Mechanical stability is achieved by printing cell-laden hydrogels together with biodegradable polymers in integrated patterns and anchored on sacrificial hydrogels. The correct shape of the tissue construct is achieved by representing clinical imaging data as a computer model of the anatomical defect and translating the model into a program that controls the motions of the printer nozzles, which dispense cells to discrete locations. The incorporation of microchannels into the tissue constructs facilitates diffusion of nutrients to printed cells, thereby overcoming the diffusion limit of 100–200 μm for cell survival in engineered tissues. We demonstrate capabilities of the ITOP by fabricating mandible and calvarial bone, cartilage and skeletal muscle. Future development of the ITOP is being directed to the production of tissues for human applications and to the building of more complex tissues and solid organs.
Pub.: 15 Feb '16, Pinned: 21 Aug '17