scholarly journals An Integrative Experimental Approach to Design Optimization and Removal Strategies of Supporting Structures Used during L-PBF of SS316L Aortic Stents

2021 ◽  
Vol 11 (19) ◽  
pp. 9176
Author(s):  
Marius Grad ◽  
Naresh Nadammal ◽  
Ulrich Schultheiss ◽  
Philipp Lulla ◽  
Ulf Noster
Keyword(s):  
Experimental Approach ◽  
Breaking Load ◽  
Structure Design ◽  
Lead Times ◽  
Material Consumption ◽  
Support Structure ◽  
Support Design ◽  
Manufacturing Time ◽  
Lower Material ◽  
Supporting Structures

One of the fundamental challenges in L-PBF of filigree geometries, such as aortic stents used in biomedical applications, is the requirement for a robust yet easily removable support structure that allows each component to be successfully fabricated without distortion. To solve this challenge, an integrative experimental approach was attempted in the present study by identifying an optimal support structure design and an optimized support removal strategy for this design. The specimens were manufactured using four different support structure designs based on the geometry exposed to the laser beam during the L-PBF. Support removal procedures included sand blasting (SB), glass bead blasting (GB), and electrochemical polishing (ECP). The two best-performing designs (line and cross) were chosen due to shorter lead times and lower material consumption. As an additional factor that indicates a stable design, the breaking load requirement to remove the support structures was determined. A modified line support with a 145° included angle was shown to be the best support structure design in terms of breaking load, material consumption, and manufacturing time. All three procedures were used to ensure residue-free support removal for this modified line support design, with ECP proving to be the most effective.

Testing and Validation of a Custom CAD Tool to Support Design for Manufacturing: An Experimental Study

2021 ◽  
Author(s):  
Apurva Patel ◽  
Joshua D. Summers ◽  
Akash Patel ◽  
James L. Mathieson ◽  
Michael P. Sbarra ◽  
...  
Keyword(s):  
Undergraduate Students ◽  
Design Tool ◽  
Mass Reduction ◽  
Experimental Conditions ◽  
Support Design ◽  
Current State ◽  
Design Activities ◽  
Time Part ◽  
The Impact ◽  
Manufacturing Time

Abstract While fundamentals of DFMA are widely accepted and used in the engineering design community, many CAD environments lack tools that address manufacturing concerns and provide rapid feedback to designers about manufacturing impacts of their design choices. This paper presents an experiment-based testing and validation of a rapid feedback tool that provides users a history-based prediction of manufacturing time based on the current state of the design. A between-subjects experiment is designed to evaluate the impact of the tool on design outcomes based on modeling time, part mass, and manufacturing time. Participants in the study included mechanical engineering graduate and undergraduate students with at least one semester of experience using SolidWorks. The experiment included three different design activities and three different conditions of the design tool. Participants completed up to three sessions with different experimental conditions. Analysis of the data collected shows that use of the design tool results in a small but nonsignificant increase in modeling time. Moreover, use of the tool results in reduced part mass on average, as well as in a within-subject comparison. Tool use reduced manufacturing time in open ended activities, but increased manufacturing time when activities focus more on mass-reduction. Participant feedback suggests that the tool helped guide their material removal actions by showing the impact on manufacturing time. Finally, potential improvements and future expansions of the tool are discussed.

Allowable Load Derivation of Single Angle Members for Small Bore Pipe Supports Welded on 4-Bolt CEA Plate in APR1400

2008 ◽  
Author(s):  
Joon-Ho Lee ◽  
Hee-Cheon Choo ◽  
Jae-Hwan Bae
Keyword(s):  
Finite Element ◽  
Nuclear Power ◽  
Steel Structures ◽  
Integrated Analysis ◽  
Piping System ◽  
Finite Element Models ◽  
Support Design ◽  
Anchor System ◽  
Consensus Standard ◽  
Supporting Structures

Single angle members have been rarely used as supporting structures in nuclear power plant because they are open sections which have significantly reduced capacities when considered in comparison to closed sections, and have weakness for twisting load such as local torsion caused by loading eccentricity of geometric center and shear center. However, in APR1400 (Advanced Power Reactor 1400 MW-class in Korea), the extended application of single angle members for supporting structures of small bore piping systems is considered to enhance the constructability and economics of plant. Furthermore, although it is general guideline for support design in APR1400 that supporting structures for equipment should be directly welded to embedded plates or steel structures in buildings as far as possible, in the case of small bore piping system, for the low level priority of construction in site, supporting steel structures for small bore piping could not be evitable to be welded onto the CEA (Concrete Expansion Anchor) plate. Per the ACI 318, ACI 349 and ACI 355.2, most CEA plate designs and anchor bolt load determinations are now based on finite element models that many applications have been individually made for CEA plates. If single angle members are attached onto these plates, integrated finite element models should be developed and analyzed in detail accroding to NRC IEB 79-02. Such a detailed analysis may appear to be excessive to small bore pipe supports which have diverse design materials and frequently subjected to field changes requiring rapid revision. Consideration should be given to reviewing current practices and reducing the level of effort being used for the integrated analysis of support and CEA plate by developing consensus standard regarding reasonable support and CEA plate designs. In this paper, allowable piping loads for single angle members such as L2×2×1/4, L2-1/2×2-1/2×1/4, L3×3×3/8, and L4×4×1/2 welded on the 4-bolt CEA assembly are derived and reviewed for general use for small bore pipe support design, and L2-1/2×2-1/2×1/4 and L3×3×3/8 welded onto 4-bolt (3/8″Φ sleeve type) CEA plate (1/2″×9″×9″) are recommended as standard small bore pipe supports with post-installed anchor system in APR1400.

scholarly journals Backbone cup – a structure design competition based on topology optimization and 3D printing

2016 ◽  
Vol 7 ◽  
pp. A1 ◽  
Author(s):  
Ji-Hong Zhu ◽  
Kai-Ke Yang ◽  
Wei-Hong Zhang
Keyword(s):  
Topology Optimization ◽  
3D Printing ◽  
Experimental Approach ◽  
Mechanical Performance ◽  
Turnaround Time ◽  
Structure Design ◽  
The Finite Element Method ◽  
New Approach ◽  
Design Competition ◽  
Testing Approach

This paper addresses a structure design competition based on topology optimization and 3D Printing, and proposes an experimental approach to efficiently and quickly measure the mechanical performance of the structures designed using topology optimization. Since the topology optimized structure designs are prone to be geometrically complex, it is extremely inconvenient to fabricate these designs with traditional machining. In this study, we not only fabricated the topology optimized structure designs using one kind of 3D Printing technology known as stereolithography (SLA), but also tested the mechanical performance of the produced prototype parts. The finite element method is used to analyze the structure responses, and the consistent results of the numerical simulations and structure experiments prove the validity of this new structure testing approach. This new approach will not only provide a rapid access to topology optimized structure designs verifying, but also cut the turnaround time of structure design significantly.

Flexible support structure design of lightweight thin reflector

2017 ◽  
Vol 38 (5) ◽  
pp. 618-622
Author(s):  
Yang Jianli ◽  
Qi Yuan ◽  
Yang Xiaoqiang ◽  
Zhu Lei ◽  
Teng Guoqi ◽  
...  
Keyword(s):  
Structure Design ◽  
Support Structure ◽  
Flexible Support

scholarly journals Probabilistic Design and Optimization for Tunnels considering Measuring Uncertainties

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhirong Jia ◽  
Hongbo Zhao ◽  
Changxing Zhu
Keyword(s):  
Test Data ◽  
Rock Strength ◽  
Triaxial Compression ◽  
Interaction Mechanism ◽  
Essential Property ◽  
Circular Tunnel ◽  
Support Structure ◽  
Support Design ◽  
Reliability Based Design ◽  
Bee Colony

Uncertainty is an essential property of rock mechanics and engineering, which is of great significance to excavation, design, and control of rock engineering. In this study, an innovative framework of the reliability-based design was developed for the rock tunnel under uncertainty. The convergence-confinement method is used to characterize the interaction mechanism between the support structure and surrounding rock mass. Artificial bee colony (ABC) was adopted to solve the optimization problem in the reliability-based design. The probabilistic properties of rock strength and failure envelope were obtained based on the triaxial compression test data using the Bayesian method. The reliability of the tunnel and support structure was evaluated based on the abovementioned probabilistic properties of rock strength using the reliability analysis method. A circular tunnel was used to illustrate the developed framework, and the procedure was presented in detail. The time of rockbolt installed, the thickness of the shotcrete, length of rockbolt, circumferential space, and longitudinal space of rockbolt were determined and met the constraints of reliability index. Results show that the developed framework can consider the uncertainty for support design in the tunnel. It provides a good and promising way to support design considering the uncertainty of test data using the reliability-based design.

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