Design Method for Conformal Lattice-Skin Structure Fabricated by AM Technologies

2016 ◽  
Author(s):  
Yunlong Tang ◽  
Sheng Yang ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Complex Geometry ◽  
Design Method ◽  
Mapping Function ◽  
Design Guidelines ◽  
Design Methods ◽  
Design Stage ◽  
Lattice Structures ◽  
Skin Structure ◽  
General Design ◽  
Geometry Model

Parts with complex geometry can be produced by additive manufacturing processes without a significant increase in fabrication time and cost. One application of AM technologies is to fabricate customized lattice-skin structures which can enhance the functional performance of products with less material and less weight. In this paper, a brief comparison between different types of lattice structures and their related design methods has been done. The result shows that conformal lattice structures may perform better than other types of lattice due to its unique configuration for some design cases. However, most existing design methods of conformal lattice have a limitation to deal with complex external geometry. To solve this issue and fully utilize conformal lattice structures, a general design method for a conformal lattice-skin structure is proposed. This design method consists of two major design stages. At the beginning design stage, conformal surfaces are selected based on proposed general design guidelines. Then two different lattice frame generation methods are provided to generate conformal lattice to fit the selected conformal surfaces. A comparison between these two methods is made to help designers select a suitable method for their design cases. In the second design stage, the thickness of each lattice strut is calculated based on a defined mapping function. This mapping function generally considers two important factors from the result of topology optimization. They are optimal relative density distribution and its related principle stress direction. Based on the calculated strut’s thickness, the geometry model of heterogeneous conformal lattice can be generated. At the end of the design process, skin structures can be added on the generated heterogeneous conformal lattice. To further illustrate and validate the proposed design method, a design case of handle connector is provided. The result of this case study shows this method can provide an efficient tool for designers to generate the conformal lattice-skin structure for a complex external shape.

Design Method for Lattice-Skin Structure Fabricated by Additive Manufacturing

2014 ◽  
Author(s):  
Yunlong Tang ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Complex Geometry ◽  
Lattice Structure ◽  
Design Method ◽  
Mapping Function ◽  
Second Step ◽  
Parameter Distribution ◽  
Skin Structure ◽  
Traditional Design ◽  
Novel Design

Parts with complex geometry structure can be produced by AM without significant increase of fabrication time and cost. One application of AM technology is to fabricate customized lattice-skin structure which can enhance performance of products with less material and less weight. However, most of traditional design methods only focus on design at macro-level with solid structure. Thus, a design method which can generate customized lattice-skin structure for performance improvement and functionality integration is urgently needed. In this paper, a novel design method for lattice-skin structure is proposed. In this design method, FSs and FVs are firstly generated according to FRs. Then, initial design space is created by filling FVs and FSs with selected lattice topology and skin, respectively. In parallel to the second step, initial parameters of lattice-skin structure are calculated based on FRs. Finally, TO method is used to optimize parameter distribution of lattice structure with the help of mapping function between TO’s result and lattice parameters. The design method proposed in this paper is proven to be efficient with case study and provides an important foundation for wide adoption of AM technologies in industry.

Teaching Multiple Approaches to Engineering Design Within a Unified Curriculum

2010 ◽  
Author(s):  
Robert L. Nagel ◽  
Kerry Poppa ◽  
Robert B. Stone
Keyword(s):  
Problem Solving ◽  
Engineering Design ◽  
Integrated Curriculum ◽  
Systematic Approach ◽  
Design Method ◽  
Design Methods ◽  
Design Approach ◽  
General Definition ◽  
General Description ◽  
General Design

This paper presents a comparison on four different, yet complimentary, design methods: (1) Pahl and Beitz’s Systematic Approach to Design, (2) Suh’s Axiomatic Design, (3) Altshuller’s Theory of Inventive Problem Solving and (4) Ulwick’s Outcome-Driven Method. To compare these approaches to design, a general definition and process for design is first derived from common engineering design texts. After a general description of each of these design approaches is presented, a comparison is made between each design approach and the general design method. The paper is concluded with the proposal of an integrated curriculum for teaching the methods within the scope of a single design course.

Requirements for Design and Environmental Assessment of Products

2012 ◽  
Author(s):  
Srinivas Kota ◽  
Daniel Brissaud ◽  
Peggy Zwolinski
Keyword(s):  
Virtual Reality ◽  
Design Method ◽  
Design Methods ◽  
Design Stage ◽  
Major Influence ◽  
User Centered Design ◽  
Virtual Reality Technology ◽  
Environmental Properties ◽  
Potential Benefits ◽  
User Centered

Companies can have competitive advantage if their products are developed with the help of users and their practice in mind. Product development needs to include user views in the design [1] as the changes to product proposals in design stage needs less effort and time and has major influence on later stages. User-centered design methods have been proposed and implemented. Virtual reality technology has been developed to support these design methods. Advances in virtual reality technologies help realize virtually not only the products but the environment in which they can be used and the actors who use them. This research aims at investigating the eco-design methods and the technology supporting them. A huge challenge in eco-design is to make clear the environmental potential of products for both the engineer and the user. The paper deals with the use of virtual reality technology to see how it can help both designer and user in design and assessment of product and its use to reduce environmental impact. Different studies are reported in literature [2], [3], and [4] but do not address the environmental properties. The paper reviews the literature to propose the requirements of a user-centered eco-design method and investigates the potential benefits of the holographic technology for this purpose.

An Update on Improved Flange Design Methods

2007 ◽  
Author(s):  
Warren Brown
Keyword(s):  
Design Method ◽  
Design Methods ◽  
Project Development ◽  
Design Improvement ◽  
Panel Session ◽  
Improved Methods ◽  
Made In

This paper details further progress made in the PVRC project “Development of Improved Flange Design Method for the ASME VIII, Div.2 Rewrite Project” presented during the panel session on flange design at the 2006 PVP conference in Vancouver. The major areas of flange design improvement indicated by that project are examined and the suggested solutions for implementing the improved methods into the Code are discussed. Further analysis on aspects such as gasket creep and the use of leakage-based design has been conducted. Shortcomings in the proposed ASME flange design method (ASME BFJ) and current CEN flange design methods (EN-1591) are highlighted and methods for resolution of these issues are suggested.

Impact of Secondary Flow on the Accuracy of Simplified Design Methods for Steam Turbine Stages

2012 ◽  
Author(s):  
Jan Schumann ◽  
Ulrich Harbecke ◽  
Daniel Sahnen ◽  
Thomas Polklas ◽  
Peter Jeschke ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Steam Turbine ◽  
Design Process ◽  
Design Method ◽  
Computing Time ◽  
Leading Edge ◽  
Design Methods ◽  
Preliminary Design ◽  
Line Design ◽  
Radial Equilibrium

The subject of the presented paper is the validation of a design method for HP and IP steam turbine stages. Common design processes have been operating with simplified design methods in order to quickly obtain feasible stage designs. Therefore, inaccuracies due to assumptions in the underlying methods have to be accepted. The focus of this work is to quantify the inaccuracy of a simplified design method compared to 3D Computational Fluid Dynamics (CFD) simulations. Short computing time is very convenient in preliminary design; therefore, common design methods work with a large degree of simplification. The origin of the presented analysis is a mean line design process, dealing with repeating stage conditions. Two features of the preliminary design are the stage efficiency, based on loss correlations, and the mechanical strength, obtained by using the beam theory. Due to these simplifications, only a few input parameters are necessary to define the primal stage geometry and hence, the optimal design can easily be found. In addition, by using an implemented law to take the radial equilibrium into account, the appropriate twist of the blading can be defined. However, in comparison to the real radial distribution of flow angles, this method implies inaccuracies, especially in regions of secondary flow. In these regions, twisted blades, developed by using the simplified radial equilibrium, will be exposed to a three-dimensional flow, which is not considered in the design process. The analyzed design cases show that discrepancies at the hub and shroud section do exist, but have minor effects. Even the shroud section, with its thinner leading-edge, is not vulnerable to these unanticipated flow angles.

Design of Cooling Towers by the Effectiveness-NTU Method

1989 ◽  
Vol 111 (4) ◽  
pp. 837-843 ◽  
Author(s):  
H. Jaber ◽  
R. L. Webb
Keyword(s):  
Heat Exchanger ◽  
Cooling Tower ◽  
Design Method ◽  
Design Methods ◽  
Parallel Flow ◽  
Basic Method ◽  
Cooling Towers ◽  
Flow Configuration ◽  
Heat Exchanger Design

This paper develops the effectiveness-NTU design method for cooling towers. The definitions for effectiveness and NTU are totally consistent with the fundamental definitions used in heat exchanger design. Sample calculations are presented for counter and crossflow cooling towers. Using the proper definitions, a person competent in heat exchanger design can easily use the same basic method to design a cooling tower of counter, cross, or parallel flow configuration. The problems associated with the curvature of the saturated air enthalpy line are also treated. A “one-increment” design ignores the effect of this curvature. Increased precision can be obtained by dividing the cooling range into two or more increments. The standard effectiveness-NTU method is then used for each of the increments. Calculations are presented to define the error associated with different numbers of increments. This defines the number of increments required to attain a desired degree of precision. The authors also summarize the LMED method introduced by Berman, and show that this is totally consistent with the effectiveness-NTU method. Hence, using proper and consistent terms, heat exchanger designers are shown how to use either the standard LMED or effectiveness-NTU design methods to design cooling towers.

Die Wertstrommethode in der Prozessindustrie*/The Value Stream Method in the process industry - Analysis of its shortcomings and recommendations for adaption

2017 ◽  
Vol 107 (04) ◽  
pp. 231-234
Author(s):  
K. Erlach ◽  
E. Sheehan ◽  
S. Hartleif
Keyword(s):  
Production Systems ◽  
Design Method ◽  
Design Guidelines ◽  
Process Industry ◽  
Joint Production ◽  
Industry Analysis ◽  
Process Industries ◽  
Good Industry ◽  
Value Stream ◽  
Different Characteristics

In der Stückgutindustrie lassen sich die acht Gestaltungsrichtlinien der Wertstrommethode nach Erlach hervorragend anwenden. In der Prozessindustrie weist die Produktion jedoch häufig andere Merkmale (beispielsweise eine Kuppelproduktion) auf, die neue Herausforderungen an die Wertstrommethode stellen. Aufbauend auf den acht Gestaltungsrichtlinien des Wertstromdesigns werden in diesem Fachbeitrag Handlungsempfehlungen für die Anwendung der Wertstrommethode in der Prozessindustrie diskutiert.   The eight design guidelines of Erlach‘s Value Stream Design Method work well in streamlining operations in the piece-good industry. In the process and chemical industries, however, production systems exhibit different characteristics, like joint production, that present challenges for the eight step value stream design method. Building on the eight design guidelines, this article discusses the deficits of this method in the process industries and gives recommendations for its adaptatio.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

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