Envelope grinding of micro-cylinder array lenses using a near arc-profile wheel without on-machine precision truing

2021 ◽  
Vol 289 ◽  
pp. 116927
Author(s):  
Wei Wang ◽  
Zhen Zhang ◽  
Peng Yao ◽  
Xiangyu Wang ◽  
Zongbo Zhang ◽  
...  
PIERS Online ◽  
2008 ◽  
Vol 4 (7) ◽  
pp. 746-750 ◽  
Author(s):  
Bing-Hung Chen ◽  
Yih-Chau Wang ◽  
Jia-Hng Lin

2020 ◽  
Vol 64 (12) ◽  
pp. 1060-1066
Author(s):  
M. K. Abubekerov ◽  
N. Yu. Gostev

Author(s):  
Michael Nierla ◽  
Alexander Sutor ◽  
Stefan Johann Rupitsch ◽  
Manfred Kaltenbacher

Purpose This paper aims to present a novel stageless evaluation scheme for a vector Preisach model that exploits rotational operators for the description of vector hysteresis. It is meant to resolve the discretizational errors that arise during the application of the standard matrix-based implementation of Preisach-based models. Design/methodology/approach The newly developed evaluation uses a nested-list data structure. Together with an adapted form of the Everett function, it allows to represent both the additional rotational operator and the switching operator of the standard scalar Preisach model in a stageless fashion, i.e. without introducing discretization errors. Additionally, presented updating and simplification rules ensure the computational efficiency of the scheme. Findings A comparison between the stageless evaluation scheme and the commonly used matrix approach reveals not only an improvement in accuracy up to machine precision but, furthermore, a reduction of computational resources. Research limitations/implications The presented evaluation scheme is especially designed for a vector Preisach model, which is based on an additional rotational operator. A direct application to other vector Preisach models that do not rely on rotational operators is not intended. Nevertheless, the presented methodology allows an easy adaption to similar vector Preisach schemes that use modified setting rules for the rotational operator and/or the switching operator. Originality/value Prior to this contribution, the vector Preisach model based on rotational operators could only be evaluated using a matrix-based approach that works with discretized forms of rotational and switching operator. The presented evaluation scheme offers reduced computational cost at much higher accuracy. Therefore, it is of great interest for all users of the mentioned or similar vector Preisach models.


2006 ◽  
Vol 16 (06) ◽  
pp. 1645-1669 ◽  
Author(s):  
SERGEJ FLACH ◽  
ANDREY GORBACH

This work provides a description of the main computational tools for the study of discrete breathers. It starts with the observation of breathers through simple numerical runs, the study uses targeted initial conditions, and discrete breather impact on transient processes and thermal equilibrium. We briefly describe a set of numerical methods to obtain breathers up to machine precision. In the final part of this work we apply the discussed methods to study the competing length scales for breathers with purely anharmonic interactions — favoring superexponential localization — and long range interactions, which favor algebraic decay in space. As a result, we observe and explain the presence of three different spatial tail characteristics of the considered localized excitations.


2020 ◽  
Vol 31 (41) ◽  
pp. 415302
Author(s):  
Yun Zhou ◽  
Jie Tang ◽  
Heng Zhang ◽  
Minghui Luo ◽  
Lei Zhou ◽  
...  

2015 ◽  
Vol 808 ◽  
pp. 3-8
Author(s):  
Miroslav Císar ◽  
Ivan Kuric ◽  
Vasile Adrian Ceclan

The article deals with diagnostics of machine tool precision and necessity to train basic routines of measurement and its preparation. Such training is essential for efficiency of diagnostic processes as preparation is usually the most time-consuming and skill-demanding part of overall measurement. The article roughly describes simulation of machine tool errors on proposed experimental device and its implementation into the training process in order to gain experiences with measurement on machine tools in wide scale of conditions. Described device is designed to simulate several geometrical errors, inaccuracies and environmental impacts on precision of positioning which affects not only machine precision but also effectivity of measurement itself.


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