Based on the investigation of large length measurement and alignment techniques in 3D construction, a laser diode alignment system for boat assembly is presented. In the system, a…
Abstract
Based on the investigation of large length measurement and alignment techniques in 3D construction, a laser diode alignment system for boat assembly is presented. In the system, a horizontal laser diode beam and a vertical light plane formed by a rotating pentagonal prism are used as a measuring datum. The system is of low cost, reliable, safe and convenient to be used on‐line in small boatyards with reasonable accuracy. The synthesised error of the system is analysed. The application of the system in boat assembly and some considerations of the system design are described.
Details
Keywords
Wenlei Zhang, Mingxu Ma, Haiyan Li, Jiapeng Yu and Zhenwei Zhang
The purpose of this paper is to discriminate fake interference caused by polygonal approximation so as to achieve accurate assembly sequence planning and assembly simulation.
Abstract
Purpose
The purpose of this paper is to discriminate fake interference caused by polygonal approximation so as to achieve accurate assembly sequence planning and assembly simulation.
Design/methodology/approach
An approximation zone model is proposed to formulate polygonal approximation. Fake interference is discriminated from hard interference by evaluating if polygonal models intersect within corresponding approximation zones. To reduce the computation, the surface-surface, surface-end face and end face-end face intersection test methods have been developed to evaluate the intersection and obtain collision data. An updated collision detection algorithm with this method is presented, which is implemented by a system named AutoAssem.
Findings
This method has been applied to a set of products such as a valve for assembly interference matrix generation, static and dynamic collision detection. The results show that it ensures the accuracy of assembly sequence planning and assembly simulation for polygonal models.
Practical implications
This method facilitates assembly design in the virtual environment with polygonal models. It can also be applied to computer aided design systems to achieve quick and accurate collision detection.
Originality/value
Fake interference between polygonal models may result in serious errors in assembly sequence planning and assembly simulation. Assembly zone model and novel polygon intersection verification methods have been proposed to effectively tackle this problem. Compared to current methods, this method considers valid penetration direction and approximation difference, does not need to process complicated auxiliary data and can be easily integrated with current collision detection methods.
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Zhenwei Li, Zhixun Wen, Cheng Wang, Ying Dai and Peng Fei He
This paper aims to provide SIF calculation method for engineering application.
Abstract
Purpose
This paper aims to provide SIF calculation method for engineering application.
Design/methodology/approach
In this paper, the stress intensity factors (SIFs) calculation method is applied to the anisotropic Ni-based single crystal film cooling holes (FCHs) structure.
Findings
Based on contour integral, the anisotropic SIFs analysis finite element method (FEM) in Ni-based single crystal is proposed. The applicability and mesh independence of the method is assessed by comparing the calculated SIFs using mode of plate with an edge crack. Anisotropic SIFs can be calculated with excellent accuracy using the finite element contour integral approach. Then, the effect of crystal orientation and FCHs interference on the anisotropic SIFs is clarified. The SIFs of FCH edge crack in the [011] orientated Ni-based single crystal increases faster than the other two orientations. And the SIF of horizontal interference FCHs edge crack is also larger than that of the inclined interference one.
Originality/value
The SIFs of the FCH edge crack in the turbine air-cooled blade are innovatively computed using the sub-model method. Both the Mode I and II SIFs of FCHs edge crack in blade increase with crack growing.