A Shape Optimal Design Methodology for Packaging Design

1992 ◽  
Vol 114 (4) ◽  
pp. 461-466 ◽  
Author(s):  
S. D. Rajan ◽  
Ben Nagaraj ◽  
Mali Mahalingam

Shape optimal design methodology has been used as a design tool in the automotive and aerospace industries for quite some time now. In the present work the hybrid natural shape optimal design approach is used along with a nonlinear programming (NLP) technique to find the optimal shapes of electronic packaging components. The design problems are formulated as min-max problems and linear and materially nonlinear finite element analyses provide the function values. The applicability of the developed methodology is illustrated using a design example that deals with the packaging design of a plastic pad array carrier digital package. The results indicate that the methodology can be used either as an effective way of evaluating different design alternatives or refining existing designs.

Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.


2012 ◽  
Vol 544 ◽  
pp. 194-199
Author(s):  
Di Zhang ◽  
Shui Ping Sheng ◽  
Zeng Liang Gao

Two important parameters of torispherical head that are (interior radius of spherical crown area) and r (interior radius of transition corner) have been optimized by the module of the large general-purpose finite-element software ANSYS, targeting the strength and stability of the head. This paper provides an optimized torispherical head, which improves the stability of the edge of the head with acceptable strength of the head. The procedure is generally applicable as a design tool for optimal design.


Author(s):  
P. Y. Shim ◽  
S. Mannoochehri

Abstract This paper presents a hybrid shape optimal design methodology using an implicit differentiation approach for sensitivity analysis and a node removal technique for shape alteration. The approach presented attempts to overcome the weaknesses inherent in each individual technique. The basic idea is to combine the sensitivity analysis, which forms the analytical basis for the algorithm, and a node removal technique, which grossly modifies the shape without the need for a remeshing after each iteration. The sensitivity analysis is based on the finite element equilibrium equation and the implicit differentiation technique. It examines the effect positional changes of the boundary nodes have on the stress values. Using the sensitivity results, a sequential linear programming algorithm is utilized to determine optimum positions of the boundary nodes. These optimization results are provided as inputs to an algorithm that decides which boundary nodes should be removed. By removing boundary nodes, the boundary elements change to either a triangular or a non-existent type. This shape modification procedure starts from the boundary elements and moves toward the internal elements. Only two iterations of finite element analysis are required to modify one boundary layer. To maintain the structural integrity and the connectivity of the elements in the model, a connectivity check is performed after each iteration. Three design examples are given to illustrate the accuracy and the steps involved in the proposed optimal design methodology.


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