scholarly journals Lapping modeling of looped warp knitted jacquard fabrics based on web

2020 ◽  
Vol 15 ◽  
pp. 155892502097930
Author(s):  
Haisang Liu ◽  
Gaoming Jiang ◽  
Zhijia Dong

In this paper a mathematical model of looped warp knitted jacquard fabric is proposed. The technology parameters cover chain notation, threading, jacquard pattern grid and so on are defined based on the matrix. A basic pattern matrix is derived from chain notation and threading using the block matrix. Then combined with the displacement data of jacquard girds, the jacquard pattern matrix is calculated. Finally, the stitch type and stitch position are obtained analyzing the pattern information in the previous matrix. Special stress is laid on the difference between two different displacement data of jacquard girds, RT = 0 and RT = 1, which results in inconsistent lapping for the same jacquard bitmap. The pattern models are implemented and the jacquard lapping bitmap and three-dimensional simulation are generated by a calculating program via Visualstudio2015 using C# and JavaScript. The results show that this model can distinguish two types displacement jacquard information. The parameter input process is simplified and the run time for calculation is also shortened. In addition, with the help of CAD system via the web, priorities including resource sharing, design-time saving, and efficiency improving are achieved.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sandang Guo ◽  
Yaqian Jing ◽  
Bingjun Li

PurposeThe purpose of this paper is to make multivariable gray model to be available for the application on interval gray number sequences directly, the matrix form of interval multivariable gray model (IMGM(1,m,k) model) is constructed to simulate and forecast original interval gray number sequences in this paper.Design/methodology/approachFirstly, the interval gray number is regarded as a three-dimensional column vector, and the parameters of multivariable gray model are expressed in matrix form. Based on the dynamic gray action and optimized background value, the interval multivariable gray model is constructed. Finally, two examples and comparisons are carried out to verify the effectiveness of IMGM(1,m,k) model.FindingsThe model is applied to simulate and predict expert value, foreign direct investment, automobile sales and steel output, respectively. The results show that the proposed model has better simulation and prediction performance than another two models.Practical implicationsDue to the uncertainty information and continuous changing of reality, the interval gray numbers are used to characterize full information of original data. And the IMGM(1,m,k) model not only considers the characteristics of parameters changing with time but also takes into account information on lower, middle and upper bounds of interval gray numbers simultaneously to make better suitable for practical application.Originality/valueThe main contribution of this paper is to propose a new interval multivariable gray model, which considers the interaction between the lower, middle and upper bounds of interval numbers and need not to transform interval gray number sequences into real sequences. According to combining different characteristics of each bound of interval gray numbers, the matrix form of interval multivariable gray model is established to simulate and forecast interval gray numbers. In addition, the model introduces dynamic gray action to reflect the changes of parameters over time. Instead of white equation of classic MGM(1,m), the difference equation is directly used to solve the simulated and predicted values.


Author(s):  
Igor Tsukrov ◽  
Michael Giovinazzo ◽  
Kateryna Vyshenska ◽  
Harun Bayraktar ◽  
Jon Goering ◽  
...  

Finite element models of 3D woven composites are developed to predict possible microcracking of the matrix during curing. A specific ply-to-ply weave architecture for carbon fiber reinforced epoxy is chosen as a benchmark case. Two approaches to defining the geometry of reinforcement are considered. One is based on the nominal description of composite, and the second involves fabric mechanics simulations. Finite element models utilizing these approaches are used to calculate the overall elastic properties of the composite, and predict residual stresses due to resin curing. It is shown that for the same volume fraction of reinforcement, the difference in the predicted overall in-plane stiffness is on the order of 10%. Numerical model utilizing the fabric mechanics simulations predicts lower level of residual stresses due to curing, as compared to nominal geometry models.


Author(s):  
Dani Fadda

A numerical simulation project, described in this paper, was assigned in an undergraduate heat transfer course in the mechanical engineering curriculum. This project complemented the heat transfer lecture course and its corresponding heat transfer lab. It was used to help students visualize and better understand the difference between conduction heat transfer which occurs within a three-dimensional solid body and the convection and/or radiation which occur at the surface of the solid body. It also allowed the students to generate and compare results of one dimensional heat transfer calculations to three dimensional simulation results. The project contained well defined deliverables and an open-ended deliverable which allowed students to be creative. It gave the students reason to discuss the course outside the classroom. It allowed students to use SolidWorks heat transfer simulation and manage a MATLAB script without taking classroom time. It was appreciated and enjoyed by the students.


2013 ◽  
Vol 805-806 ◽  
pp. 1763-1770
Author(s):  
Chun Lan Mo ◽  
Wen Zhong ◽  
Wei Guan ◽  
Wei Wei ◽  
Hao Zhong Huang ◽  
...  

The thermodynamic cycle analysis of diesel engines using the engine cycle simulation programs is feasible. The comparison of dual and LIVC miller cycles engine fueled with ED10 diesel/ethanol blends on temperature and emissions are investigated by simulation. From the comparison, +0.85 EIVC miller cycle is a selection for an optimizing point of miller cycle ratio, i.e, the intake valve timing of the engine is good for NO emission, SOOT emission and the engine power output. The difference of EIVC and LIVC miller cycle was studied. The results show the tendency of performance with EIVC miller cycle is similar to that of LIVC miller cycle. But the peak cylinder combustion temperature of EIVC miller cycle become lower relative to LIVC miller cycle, which lead to slightly lower NO emission and slightly higher SOOT emission for EIVC miller cycle.


2018 ◽  
Vol 11 (11) ◽  
pp. 5981-6002 ◽  
Author(s):  
Xinhua Zhou ◽  
Qinghua Yang ◽  
Xiaojie Zhen ◽  
Yubin Li ◽  
Guanghua Hao ◽  
...  

Abstract. A sonic anemometer reports three-dimensional (3-D) wind and sonic temperature (Ts) by measuring the time of ultrasonic signals transmitting along each of its three sonic paths, whose geometry of lengths and angles in the anemometer coordinate system was precisely determined through production calibrations and the geometry data were embedded into the sonic anemometer operating system (OS) for internal computations. If this geometry is deformed, although correctly measuring the time, the sonic anemometer continues to use its embedded geometry data for internal computations, resulting in incorrect output of 3-D wind and Ts data. However, if the geometry is remeasured (i.e., recalibrated) and to update the OS, the sonic anemometer can resume outputting correct data. In some cases, where immediate recalibration is not possible, a deformed sonic anemometer can be used because the ultrasonic signal-transmitting time is still correctly measured and the correct time can be used to recover the data through post processing. For example, in 2015, a sonic anemometer was geometrically deformed during transportation to Antarctica. Immediate deployment was critical, so the deformed sonic anemometer was used until a replacement arrived in 2016. Equations and algorithms were developed and implemented into the post-processing software to recover wind data with and without transducer-shadow correction and Ts data with crosswind correction. Post-processing used two geometric datasets, production calibration and recalibration, to recover the wind and Ts data from May 2015 to January 2016. The recovery reduced the difference of 9.60 to 8.93 ∘C between measured and calculated Ts to 0.81 to −0.45 ∘C, which is within the expected range, due to normal measurement errors. The recovered data were further processed to derive fluxes. As data reacquisition is time-consuming and expensive, this data-recovery approach is a cost-effective and time-saving option for similar cases. The equation development can be a reference for related topics.


2013 ◽  
Vol 722 ◽  
pp. 441-446
Author(s):  
Guo Li Pang ◽  
Dan Qi Chen ◽  
Meng Huang

GIS geographic information system algorithm are able to be used in the disaster initialization period, middle and rescue stage for the advanced two-dimensional simulation technology with its geographical model as well as providing us with accurate and quick geographical indicators, with the estimation of building distribution and mountain damaged condition, can bring us extremely high value in use. But the traditional GIS algorithm also has tremendous convenience, namely we can't form accurate analysis of the buildings and streets form three dimensional regions, we cannot tell the difference between topographic change quantities as well, resulting in certain circumstances that the algorithm is no practical. This article puts forward 3d and 2d embedded GIS algorithm according to the satellite remote sensing technology, which can be used to cope with buildings and streets for disaster situation simulation and analysis, through this algorithm we are able to obtain the original data before a disaster, disaster failure scene and the distribution of post-disaster construction. With verification, this algorithm has high practical value and can shorten the fitting time of data.


Author(s):  
Rodney J. Clifton ◽  
Jian-Juei Wang

Abstract This paper presents an adaptive optimal mesh generator, including criteria for determining the boundary nodal coordinates. This mesh generator has been developed to provide mesh for a planar fracture surface in the three-dimensional simulation of hydraulic fracturing. The mesh generator is based on the optimization of the local aspect ratio by minimizing the difference of the principal stretches in mapping a square reference mesh onto the fracture surface. Sector areas, curvatures along the fracture boundary, and the locations of the corner nodes are used to calculate weights in determining the locations of the boundary nodes of the advancing fracture surface. Hydraulic fracturing simulation examples of various meshes are presented with discussion of the weighing parameters used in locating the boundary nodes.


Author(s):  
B. Carragher ◽  
M. Whittaker

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.


Author(s):  
Kenneth H. Downing

Three-dimensional structures of a number of samples have been determined by electron crystallography. The procedures used in this work include recording images of fairly large areas of a specimen at high tilt angles. There is then a large defocus ramp across the image, and parts of the image are far out of focus. In the regions where the defocus is large, the contrast transfer function (CTF) varies rapidly across the image, especially at high resolution. Not only is the CTF then difficult to determine with sufficient accuracy to correct properly, but the image contrast is reduced by envelope functions which tend toward a low value at high defocus.We have combined computer control of the electron microscope with spot-scan imaging in order to eliminate most of the defocus ramp and its effects in the images of tilted specimens. In recording the spot-scan image, the beam is scanned along rows that are parallel to the tilt axis, so that along each row of spots the focus is constant. Between scan rows, the objective lens current is changed to correct for the difference in specimen height from one scan to the next.


Author(s):  
R.A. Herring

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.


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