Effects of low-temperature transformation and transformation-induced plasticity on weld residual stresses: Numerical study and neutron diffraction measurement

In this paper, three-dimensional static and free vibration analysis of functionally graded graphene platelets-reinforced composite (FG-GPLRC) truncated conical shells, cylindrical shells and annula...

Static and free vibration analysis of graphene platelets reinforced composite truncated conical shell, cylindrical shell, and annular plate using theory of elasticity and DQM

Supplier selection process in an integrated construction materials management model

Purpose
The purpose of this meta-analysis was to evaluate the prognostic value of standard uptake value (SUV) from serial Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with head and neck cancer.

18F-FDG PET or PET-CT to evaluate prognosis for head and neck cancer: a meta-analysis

A general Fourier solution for the vibration analysis of composite laminated structure elements of revolution with general elastic restraints

Background The utility of 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in oral cavity cancer has received little attention in a clinician's perspective. We systematically evaluated the clinical roles of FDG PET in patients with oral cavity squamous cell carcinomas (SCCs). Methods Between August 2001 and February 2005, 82 new patients with resectable oral cavity SCCs underwent CT/MRI and FDG PET at initial staging and follow-up. The sensitivity and specificity of CT/MRI and FDG PET for neck metastases were compared with histopathologic reference of 67 patients who underwent neck dissection. The relationships between the maximal standardized uptake value (SUV) of primary tumors and clinicopathologic parameters, such as gender, age, tumor thickness, local invasiveness, T and N categories, tumor-node-metastasis stage, and histological grade, as well as with disease-free survival (DFS), were assessed. Results FDG PET was more sensitive than CT/MRI for detecting cervical metastases on a level-by-level basis (38/43 vs . 28/43; P  = 0.002). Age, T and N categories, tumor thickness (>8 mm) and SUV (>5.0) were also significant variables of 3-year DFS in univariate analysis. T category was an independent determinant of DFS in multivariate analysis ( P Conclusion FDG PET may have potential roles in initial staging, survival prediction, and the detection of recurrences and second cancers.

Utility of FDG PET in patients with squamous cell carcinomas of the oral cavity

At most shipyards, flame bending has been widely used to fabricate curved shells. Since residual deformation of flame bending is produced by thermo-elastic-plastic strains, it is difficult to accurately achieve the desired shape. Therefore, mechanical bending processes such as multi-press forming and multi-point press forming have become attractive because such processes can accurately control the desired shape. Springback is one of the major problems associated with mechanical bending. When the pressing tools are removed after the loading stage, the workpiece springs back due to the elastic recovery and the shape deviation needs to be compensated. The tools of the press forming process therefore need to be changed in order for the produced surface to reach the desired shape accurately after springback. Generally, forming tools are designed and constructed to operate through an iterative process in which the die and the pistons are adjusted to compensate for springback after a pressing operation. Such adjustments require significant time and effort. Therefore, the present study investigates not only how to simulate springback deformation, but also the degree of adjustment required to the stroke of pistons in multi-press forming. Finite Element Analysis (FEA) of thick metal forming and an iterative displacement adjustment algorithm are integrated for practical application. Shape deviations between the design surface and the deformed plate are minimized to reach the desired shape.

Springback adjustment for multi-point forming of thick plates in shipbuilding

A fully automated line heating (LH) process includes a control system (software) and an automated machine (hardware). The software and hardware need to be developed concurrently in order to verify and maximize the efficiency of the new process. However, most shipyards have developed these separately for an automated LH process. The development also involves extensive calculations of computer-aided design, manufacturing, and engineering (CAD/CAM/CAE) information. Thus, it cannot be user friendly for technicians. The objective of this paper is to describe the entire engineering concept for the automation of LH process. Based on the object-oriented methodology, a control system and an automated machine were developed simultaneously. The main function of the control system is to provide real-time heating information to technicians or automated machines. The information includes heating location, torch speed, heating sequence, and other related information. These data are derived from CAD/CAM/CAE applications. With the calculated heating information, the machine provides automated LH tasks and collects relevant information during and after the task. The developed system shows a user-friendly capability for shipyard operators and includes advanced engineering calculations for accurate plate fabrication. A specific example was performed, in order to verify the system. Details of the applications will be described in the paper.

User-Friendly, Advanced Line Heating Automation for Accurate Plate Forming

PLM (Product Lifecycle Management) as well as enterprise information systems commonly use the BOM (Bill of Material) as a means of communication during product development. BOM has been used for product design, production scheduling, procurement, manufacturing and maintenance as it contains the part list of a subassembly or assembly product. BOM currently plays a key role in the PLM environment because it is an essential product information platform in the industry. In practice, product data should be arranged based on the BOM and product structure. Many shipyards or PLM vendors have attempted to develop a PLM adequate for shipbuilding. However, it is always the premise of the successful PLM implementation to prepare the efficient product structure and BOM. This paper suggests an enterprise BOM which addresses the hierarchy of parts and assembly, product structure and product information of outfitting equipment in marine vessel design. In order to express the evolution of product structures and outfitting information during the ship design, the enterprise BOM is modeled by the structure BOM and the display BOM. Concepts are developed for modeling all levels of product relations with a uniform set of relationships supported by the enterprise BOM. It is shown that the architecture of the structure BOM can be used to define the relationships between assemblies, parts, and a multi-view of an evolutional BOM in ship design. The architecture of the outfitting BOM is also presented using an example of a piping system.

Integration of evolutional BOMs for design of ship outfitting equipment

Free vibration of symmetric and antisymmetric cross-ply composite laminated truncated conical shells using the spline function technique is studied. The equilibrium equations for a truncated conical shells are formulated including first-order shear deformation theory. The equations of motion are derived in terms of displacement functions and rotational functions using stress–strain and strain–displacement relationships. The coupled differential equations are solved using Bickley-type splines to obtain the generalized eigenvalue problem by combining suitable boundary conditions. The convergence and comparative results are presented. Both symmetric and anti-symmetric cross-ply shells are considered using various types of material properties. Parametric studies are made to investigate the effect of transverse shear deformation on the frequency parameter with respect to the thickness ratio, length ratio, cone angle, and circumferential mode number using different numbers of layers under various types of boundary conditions.

Jang-Hyun Lee

Papers

Utility of FDG PET in patients with squamous cell carcinomas of the oral cavity

Springback adjustment for multi-point forming of thick plates in shipbuilding

User-Friendly, Advanced Line Heating Automation for Accurate Plate Forming

Integration of evolutional BOMs for design of ship outfitting equipment

Vibration analysis of cross-ply laminated truncated conical shells using a spline method