A typical contemporary computerized product develop me nt workflow is outlined in Fig.1. Product geometry information is first prep ared with computer-aided design (CAD) software. The CAD format can then be com munica...A typical contemporary computerized product develop me nt workflow is outlined in Fig.1. Product geometry information is first prep ared with computer-aided design (CAD) software. The CAD format can then be com municated to other downstream-computerized applications like, computer-aided e ngineering analysis (CAE), computer-aided manufacturing (CAM) and/or rapid prot otyping. Since design may need to be modified to incorporate new requirements, a loop back path is also depicted in Fig.1. The design engineers will check ac cording to their experience, result of physical test and CAE simulation to decid e whether redesign is needed or not. If the design passes all tests, its pr ototype or product can be produced. Otherwise, the current practice is to chang e its geometry and/or select a more appropriate material. The iteration repeat s until the latest version satisfies the engineering specification and customer requirements. Note that the material is homogeneous in the part to be designed. With the advent of functionally graded material (FGM) research, a new workflow will become possible. Components incorporating FGM’s can be designed to achieve levels of performance superior to that of homogeneous materials by combining the desirable properties of each constituent phase. Theoretically, the material composition can be tailo red within a component to achieve local control of properties; for example, form ability, corrosion resistance, hardness, toughness, and so on. By such local co ntrol, monolithic components can be created that integrate the function of multi ple discrete components, saving part count, space, weight, and enabling concepts that would otherwise be impractical. Controlling the spatial distribution of p roperties via composition will allow for control of the state of the entire comp onent (the state of residual stress in a component). There are various methods p roposed to produce FGM components. In particular, solid freeform fabrication ( SFF) methods are commonly used to directly fabricate an FGM part in an additive fashion directly from a computer controlled, layer-by-layer, additive process in which a standard CAD is sliced into a series of horizontal planes. Common SF F techniques being investigated include three-dimensional printing (3DP), Lamin ate Object Manufacturing (LOM), Extrusion Freeform Fabrication (EFF), Selective Laser Sintering (SLS) and even Stereolithography (SL). Fig.1 Current CAE design workflow Fig.2 Proposed CAE design workflow for FGM Albeit the feasibility to fabricate FGM components, one gap still needs to be fi lled for real life FGM product design; namely, where and how to grade the compon ent. This paper will, thus, address issues on incorporating FGM for design impr ovement. Rather than changing the geometry or reselecting a new material, a FGM approach can be employed in design enhancement as shown in Fig.2. The same geo metry and material is retained except that functional property in needed regions is selectively reinforced. As in conventional workflow, CAE simulation is perf ormed after CAD modelling. CAE simulation is preferred since physical test is v ery expensive and most of them are destructive. Moreover, the experience of the engineers may not be accurate. More importantly, the result of CAE simulation is used in this research to produce a stress intensity map for selective reinfor cement. The map will be converted to tool path control signals for generating FG component via SFF machine. On the implementation side, SolidWorks is used fo r CAD modeling, COSMOS/Works is used for CAE simulation. The model is then selec tively reinforced according to the simulation result to produce a FGM enriched p ath plan to drive the Z-corp machine. Case studies are performed to verify the approach. The preliminary result is positive. Future extension to material oth er than starch and plaster powders and enhancement other than stress distributio n may be explored. In conclusion, a CAE-based methodology for FGM product des ign展开更多
文摘A typical contemporary computerized product develop me nt workflow is outlined in Fig.1. Product geometry information is first prep ared with computer-aided design (CAD) software. The CAD format can then be com municated to other downstream-computerized applications like, computer-aided e ngineering analysis (CAE), computer-aided manufacturing (CAM) and/or rapid prot otyping. Since design may need to be modified to incorporate new requirements, a loop back path is also depicted in Fig.1. The design engineers will check ac cording to their experience, result of physical test and CAE simulation to decid e whether redesign is needed or not. If the design passes all tests, its pr ototype or product can be produced. Otherwise, the current practice is to chang e its geometry and/or select a more appropriate material. The iteration repeat s until the latest version satisfies the engineering specification and customer requirements. Note that the material is homogeneous in the part to be designed. With the advent of functionally graded material (FGM) research, a new workflow will become possible. Components incorporating FGM’s can be designed to achieve levels of performance superior to that of homogeneous materials by combining the desirable properties of each constituent phase. Theoretically, the material composition can be tailo red within a component to achieve local control of properties; for example, form ability, corrosion resistance, hardness, toughness, and so on. By such local co ntrol, monolithic components can be created that integrate the function of multi ple discrete components, saving part count, space, weight, and enabling concepts that would otherwise be impractical. Controlling the spatial distribution of p roperties via composition will allow for control of the state of the entire comp onent (the state of residual stress in a component). There are various methods p roposed to produce FGM components. In particular, solid freeform fabrication ( SFF) methods are commonly used to directly fabricate an FGM part in an additive fashion directly from a computer controlled, layer-by-layer, additive process in which a standard CAD is sliced into a series of horizontal planes. Common SF F techniques being investigated include three-dimensional printing (3DP), Lamin ate Object Manufacturing (LOM), Extrusion Freeform Fabrication (EFF), Selective Laser Sintering (SLS) and even Stereolithography (SL). Fig.1 Current CAE design workflow Fig.2 Proposed CAE design workflow for FGM Albeit the feasibility to fabricate FGM components, one gap still needs to be fi lled for real life FGM product design; namely, where and how to grade the compon ent. This paper will, thus, address issues on incorporating FGM for design impr ovement. Rather than changing the geometry or reselecting a new material, a FGM approach can be employed in design enhancement as shown in Fig.2. The same geo metry and material is retained except that functional property in needed regions is selectively reinforced. As in conventional workflow, CAE simulation is perf ormed after CAD modelling. CAE simulation is preferred since physical test is v ery expensive and most of them are destructive. Moreover, the experience of the engineers may not be accurate. More importantly, the result of CAE simulation is used in this research to produce a stress intensity map for selective reinfor cement. The map will be converted to tool path control signals for generating FG component via SFF machine. On the implementation side, SolidWorks is used fo r CAD modeling, COSMOS/Works is used for CAE simulation. The model is then selec tively reinforced according to the simulation result to produce a FGM enriched p ath plan to drive the Z-corp machine. Case studies are performed to verify the approach. The preliminary result is positive. Future extension to material oth er than starch and plaster powders and enhancement other than stress distributio n may be explored. In conclusion, a CAE-based methodology for FGM product des ign
