Design for Disassembly with Heat Reversible Locator-Snap System
As recent legislative and social pressures drive manufacturers to consider effective part reuse and material recycling at the end of product life at the design stage, it becomes crucial to design and use joints that can disengage with minimum labor, part damage, and material contamination. This project presents a unified method to design high-stiffness reversible locator-snap system that can disengage non-destructively with localized heat. The problem is posed as an optimization problem to find the orientations, numbers, and locations of locators and snaps, and the number, locations and sizes of heating areas, which realize the release of snaps with minimum heating and maximum stiffness, while satisfying all motion and structural requirements.
Design for Product-Embedded Disassembly
Design for product-embedded disassembly is a new approach to Design for Disassembly that aims at designing products with built-in disassembly means to be activated at the end of product life. the relative motions of components are constrained by the locators (tabs, slots, lips, rests, etc) integral to the components, in such a way that the removal of one or few fasteners would cause the self-disintegration of the assembly in a unique sequence, much like the domino effect.
Design for Crash Satety using Equivalent Mechanism Models
The goal of this project is to develop an efficient method for vehicle crashworthiness design based on a reduced-order model of vehicle structures, called “equivalent” mechanism (EM) model. An equivalent mechanism (EM) model is a network of rigid links with lumped masses connected by prismatic and revolute joints with nonlinear springs, which approximate aggregated behaviors of structural members during crush. An EM model of a vehicle is optimized by selecting the nonlinear springs among the ones realizable by thin-walled beams. The optimum EM model serves to identify a good crash mode (CM), the time history of collapse of the structural members, and to suggest the sizes of the structural members to attain it. After the optimization, the FE model of an entire structure is “assembled” from the suggested dimensions, which is further modified to attain the good CM identified by the optimum EM model.
Top-Down Structural Assembly Synthesis
Most structural products have complex geometry to meet customer’s demand of high functionality with enhanced structural stability. Since manufacturing those products in one piece is either impossible or uneconomical, most structural products are assemblies of components with simpler geometries. The conventional way to design structural assemblies is to design overall geometry first, and then decompose the geometry to determine the part boundary and joint locations. This two-step process, however, can lead to sub-optimal design since the product geometry, even if optimized as one piece, would not be optimal after decomposition. The objective of this research is the development of top-down methodology that synthesizes structural assemblies directly from the design specifications, without going through the two-step process.
Assembly Synthesis for Robust Dimensional Integrity
The goal of this project is to develop a computational method to design an assembly and the corresponding fixture schemes and assembly sequence, such that the dimensional integrity of the assembly is insensitive to the dimensional variations of individual parts. The method recursively decomposes a given product geometry into two subassemblies until parts become manufacturable. At each recursion, joints are assigned to the interfaces between two subassemblies to ensure the in-process dimensional adjustability and proper part constraints.
Assembly Synthesis for Component Modularity
The goal of this project is to develop a computational method to identify modular structural components that are sharable among multiple structures. The method simultaneously decomposes the multiple structures with given geometries such that the reduction of structural strength of each structure due to the introduction of joints, and the overall manufacturing cost are minimized. The types of welded joints at component interfaces are selected from a given library, and the manufacturing costs of components are estimated under given production volumes considering the economies of scale. A multi-objective genetic algorithm is utilized to allow effective examination of trade-offs between manufacturing cost and structural strength.
Robust Co-Design of Products and Production Systems
The goal of this project is to develop a computational method for allocating production capacity among flexible and dedicated machines based on uncertain demand forecasts of products in a production portfolio. Given multiple scenarios of future demands with the associated probabilities, the method provides alternative capacity allocations by quantifying the expected values of the product quality and cost. The product quality is estimated as the total performance variations from the nominal design for each product in a portfolio. The production cost is estimated as the total annual equivalent of investment and operation costs for each production period. A multi-objective genetic algorithm is utilized to compute the Pareto-optimal capacity allocations that quantify the trade-offs between the expected product quality and cost. Case studies on an automotive valvetrain production demonstrated that the allocation of flexible machines is encouraged only at production steps critical to quality and cost under the demand forecasts with low uncertainty.
ChemReader : Automated Annotation of Chemical Structural Database
As biological/chemical research has become increasingly data intensive, it is invaluable to link each resource with published relevant information. In this project, we are developing an automated annotation system, ChemReader, for recognizing chemical structure diagrams in research articles and linking them with molecules in the chemical structure database. By annotating each molecule in the database with one or more relevant links to the scientific literature, the database would be a more useful resource to bio/chemical research scientists.
Molecular Docking Simulation for Flexible Protein
In drug discovery researches, it is necessary to screen of millions of compounds for a particular receptor such as protein and DNA. In order to enhance such screens, novel molecular docking tools which can predict accurately the bound conformation and interaction energy between small organic molecules (the ligand) and biomacromolecules (the receptor) are essential. The goal of our research is to build a molecular model able to represent both receptor’s and ligand’s dynamics and to develop an optimization method to explore conformational space effectively.
