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5.5 Analysis procedure and boundary conditions A transient elastostaic analysis is planned to assess the influence of the deposition scheme on the mechanical characteristic of the final shell type parts. Each model is partitioned into two parts, so as to create 25 points on the top surface, for the specification of the compressive load, simulating the three point bending conditions. The load is equally distributed at the nodes on the top of the curvature, as shown in Figs 5.10 and 5.11 in the case of flat and curved layer parts respectively. The load vales at each node increases during the selected time interval, from 0 to -30 N, thus allowing for the total load to vary from 0 to -750 N. All the nodes on the bottom surfaces of the flat portions are fixed in the vertical direction. All these conditions allow the three point bending experimental conditions to be simulated closely. The total number of elements and nodes being high, each of the analyses takes considerable amount of computational time. Field output requests and history of field outputs need to be specified in Abaqus, so as to be able store and retrieve data for postprocessing and recording the results for further discussion. Fig. 5.10 Load and boundary conditions in the case of the flat layer FDM model 114
Fig. 5.11 Load and boundary conditions in the case of the curved layer FDM part 5.6 Results and discussion A lot of data is generated from the finite element analysis of the stress fields of the two parts in terms of displacements and various stress components. However, the finite element results are mainly considered to compare the maximum displacement values with the maximum allowable displacement of the material as generated by the tensile test conducted on the raw material and presented in the load-displacement diagram of Fig. 5.6. The reason for this is a lack of experimental data on other parameters. The distribution of the stress components will also be used, but mainly to assess the stress patterns generated in different material deposition schemes. Each of the model is analysed for a time dependent variation of the applied loads. Fig. 5.12 presents a series of screen shots showing the gradual increase in the applied load and the corresponding variation in the displacement. There is a peculiar problem observed in the case of the flat layer FDM model, the applied load is concentrated at a few points, in a very narrow zone. The component assumes a completely distorted shape, and to reach the target load of 400-500 N overall, it was necessary to increase the total of nodal loads beyond 900 N. The model was tested a number of times, with all load and boundary conditions repeatedly checked, but the end result was the same. It was finally concluded that the relatively weak interaction between the flat layers, in particular at regions, where the part bends into a curved shape from the flat portions leads to an early failure and the strands are almost 115
Page 1 and 2:
An Investigation into curved layer
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Contents Abstract..................
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3.5.2 Fabepoxy.....................
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methodology to print simple curved
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List of Figures 1.1 The Rapid proto
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4.3 Parts being tested with Hounsfi
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List of Abbreviations 3D: Three dim
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Fig 1.1 The Rapid prototyping Cycle
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1.1.1 Stereolithography Stereolitho
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The object to be made is first mode
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1.1.5 Laser Engineered Net Shaping
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1.2 Fused Deposition Modeling A det
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Fig 1.8 Deposition Head Different t
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900mc is capable of producing parts
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noted that the parts built in this
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structure. Honeycomb scaffold archi
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optimal direction to build a part t
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processing treatment was analyzed w
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The actual influence of the curved
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Separating the Main part with its s
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limited to simple models. It could
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Fig 2.2 Faces, Edges and Vertices o
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2.1.5 Constructive Solid Geometry C
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A STL file is a triangular represen
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Fig 2.8 A sample Binary STL File Sl
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Different processes may either vary
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At the very outset of generating th
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and correction of each point to sat
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apid prototyping machine are remove
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Fig 2.13 Main Part Fig 2.14 Support
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As this text file is to be used wit
Page 63 and 64: mounted to the axes carriage. Timin
Page 65 and 66: Fig 3.1 The deposition head At the
Page 67 and 68: 3.2.3 Assembling Electronics and ca
Page 69 and 70: microcontroller is now disconnected
Page 71 and 72: The relationship between test point
Page 73 and 74: on the mechanical properties and po
Page 75 and 76: 3.5.1 Silicone with other materials
Page 77 and 78: Fab@home machine. Since our require
Page 79 and 80: are printed using the two suitable
Page 81 and 82: The support structure‟s dimension
Page 83 and 84: machine Fig 3.13 Flat and curved la
Page 85 and 86: 4.1 Experimental conditions Chapter
Page 87 and 88: have many factors from contention a
Page 89 and 90: 4.3 Taguchi methods There are two t
Page 91 and 92: Such steps usually identify the nee
Page 93 and 94: Nominal is best Larger is better S
Page 95 and 96: Control of material flow - The lead
Page 97 and 98: Fig 4.3 Parts being tested with Hou
Page 99 and 100: values in all cases are almost doub
Page 101 and 102: level. The other parameters were in
Page 103 and 104: The finite element method has had a
Page 105 and 106: performance of finished FDM parts [
Page 107 and 108: ehaviour with failure occurring at
Page 109 and 110: Fig. 2 (a) is the thin curved part
Page 111 and 112: Table 5.1 Property data: Fabepoxy M
Page 113: optimum number. The final finite el
Page 117 and 118: overall deflection pattern of two s
Page 119 and 120: Fig. 5.13 Variation of compressive
Page 121 and 122: Fig. 5.15 shows the overall deforma
Page 123 and 124: The effectiveness of the deposition
Page 125 and 126: [11] M. Greul, T. Pintat, M. Greuli
Page 127 and 128: [32] Philip J. Ross, 1988, “Taguc
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