Design for Additive Manufacturing of Functionally Graded Lattice Structures: A Design Method with Process Induced Anisotropy Consideration

Cong Hong Phong Nguyen,Youngdoo Kim,Young Choi 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.1

Lattice structures are well-known as a solution for designing parts with lightweight and multifunctional characteristics. Owing to the advancement of additive manufacturing (AM), the development of design methods for additively manufactured lattice structures has extensively progressed, especially for functionally graded lattice structures (FGLS). Despite plenty of available design frameworks, the application of AM constraints in the design of FGLS is limited to geometric issues. Further, there is a lack of design methods that consider the unique physical properties of additively manufactured parts, especially the anisotropic characteristics induced by AM processes. This paper proposes a novel method for the design of additively manufactured functionally graded lattice structures with the consideration of AM anisotropic properties. In addition, a customized anisotropic AM-Lattice material model that supports the design of FGLS through the density-variable topology optimization is proposed. Moreover, Fused Deposition Modeling (FDM) process in which the process-induced anisotropy of AM is clearly demonstrated is focused. The design method was validated by the three-point bending-beam design problem, a classical design problem for validating topology optimization. The results, showing agreements between simulations and experiments, prove the validity and practicality of the proposed method.

Implicit-based computer-aided design for additively manufactured functionally graded cellular structures

Nguyen Cong Hong Phong,Kim Youngdoo,Do Quang Thang,Choi Young 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.3

Additive manufacturing has enabled the fabrication of complex structures such as cellular structures. Although numerous design frameworks have been proposed for cellular structures, their effectiveness was limited owing to the use of B-rep-based representation. To address the limitations in previous research, this study proposes an implicit-based computer-aided design framework customized for additively manufactured functionally graded cellular structures (AM-FGCSs). The proposed design framework effectively aids in both single- and multiscale structural optimization for designing FGCSs. Moreover, implicit-based modeling afforded a reliable geometric representation that could efficiently assist computation tasks such as visualization, validation, and process planning for fabrication. In addition, two case studies were conducted to demonstrate the effectiveness of the proposed framework for designing FGCSs. The first case study on a three-point bending beam design problem proved the practicality of implicit-based representation in multiscale structural design. Meanwhile, the second case study validated the proficiency of the proposed framework in process planning for fabrication and engineering analysis, the two most vital computation tasks in designing cellular structures.

Combination of Boundary Representation (B-rep) and Mesh Representation for 3D Modeling in Collaborative Engineering Involved in Plant Engineering

Cong Hong Phong Nguyen,Young-doo Kim,최영 한국CDE학회 2018 한국CDE학회 논문집 Vol.23 No.1

Plant engineering projects are vast and complex, involving cooperation between various engineering fields. 3D geometry data plays an essential role in aiding the engineering collaboration. Collaborative engineering commonly uses two representation methods, namely, boundary representation (B-rep) and mesh representation. Their advantages and disadvantages lead to a gap in 3D modeling procedures. In this paper, a new representation method that combines B-rep and mesh representation in one model for 3D modeling was proposed. The data structure and conversion technology for the proposed representation method was also developed. Despite certain limitations in watertight modeling, the new representation method when compared with the traditional representation method showcased its benefits in both memory requirement as well as processing time.

Comparison of point cloud data and 3D CAD data for on-site dimensional inspection of industrial plant piping systems

Nguyen, Cong Hong Phong,Choi, Young Elsevier 2018 AUTOMATION IN CONSTRUCTION - Vol.91 No.-

<P><B>Abstract</B></P> <P>Inspection is vital in industrial plant construction and management. However, traditional inspection methods that rely on human involvement and paper documentation are becoming untenable as modern industrial plants are becoming larger and more complex than legacy facilities. Hence, an efficient and robust method is required to support the inspection of modern industrial plants. In this paper, an improved technique relying on terrestrial laser scanning (TLS) for data acquisition and normal-based region growing and efficient random sample consensus (RANSAC) for point cloud data processing is proposed for the on-site dimensional inspection of the piping systems of an industrial plant. Consequently, the as-built condition of the plant is assessed via a distance-based deviation analysis and a comparison of geometric parameters between the as-designed and as-built models. The method is validated using a dataset acquired from a compartment of a ship has verified the robustness and reliability of the proposed approach.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Point cloud data and 3D CAD data comparison for on-site dimensional inspection. </LI> <LI> Normal-based region growing and efficient RANSAC for point cloud processing. </LI> <LI> As-built dimensional condition verification with distance-based deviation analysis and geometric parameter comparison. </LI> </UL> </P>

Lightweight design with metallic additively manufactured cellular structures

Nguyen Phong Cong Hong,Kim Youngdoo,Choi Young 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

Lightweight design is essential in modern product development and is prevalent in automotive, aerospace, and biomedical applications. The utilization of cellular structure, aided by advancements in additive manufacturing, is among the most effective methods for achieving lightweight design without sacrificing structural integrity and functionality. In this paper, a stress-based structural optimization method is proposed for the design of lightweight components filled with octet functionally graded cellular structures fabricated using selective laser melting (SLM) with the AlSi10Mg alloy. The proposed method includes two main parts: the homogenization-based characterization of SLM-octet-cellular structures and the utilization of the characterized cellular structures for lightweight structure optimum design. Tensile and compression experiments were utilized to validate the proposed homogenization-based characterization method, showing that the simulation and experimental results were in agreement. In addition, the effectiveness of the proposed design optimization method was validated using the three-point bending beam design problem. The experimental results revealed that components filled with functionally graded cellular structures can withstand 15.25$\%$ more load than those with uniform cellular structures. This investigation presents a complete, validated, and industry-oriented lightweight design method, which is useful for the development of future green products.

Optimal Design of Cellular Structures with Void-Induced Anisotropy

김영두(Youngdoo Kim),응웬콩홍퐁(Cong Hong Phong Nguyen),최영(Young Choi) Korean Society for Precision Engineering 2021 한국정밀공학회지 Vol.38 No.1

Trifluralin in aquatic products: QuEChERS and Gas chromatography-tandem mass spectrometry for trace amount detection

Le-Thi Anh-Dao,Do Minh-Huy,Vo Hong-Phong,Nguyen Cong-Hau 한국분석과학회 2023 분석과학 Vol.36 No.5

In the present study, an analytical method was proposed for detecting trifluralin in aquatic products at trace concentrations. The method employed QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) as the sample preparation and measurement, respectively. The effect of the aqueous phase volume used in the QuEChERS was demonstrated, and the ratio of 10:10 (mL) between water and acetonitrile phase was used for 5 g of sample. Besides, dSPE using C18 and primary-secondary amine (PSA) was applied to remove the potential interferences from the food matrices, indicating no remarkable analyte loss. The linear range was built up from 0.50 μg L–1 to 3.0 μg L–1 (R2 = 0.9993). Other criteria, i.e., repeatability (RSDr = 0.86-1.96 %), reproducibility (RSDR = 1.09-2.01 %), and recovery (over 90 %), were in accordance with Appendix F of AOAC (2016) for method performance. Although no trifluralin was detected for the commercial samples (fish, shrimp, and breaded shrimp), the spiked samples performed favorable recoveries and precision.