A Novel Simulation Method of Micro-Topography for Grinding Surface

A novel simulation method of microtopography for grinding surface was proposed in this paper. Based on the theory of wavelet analysis, multiscale decomposition of the measured topography was conducted. The topography was divided into high frequency band (HFB), theoretical frequency band (TFB), and low frequency band (LFB) by wavelet energy method. The high-frequency and the low-frequency topography were extracted to obtain the digital combination model. Combined with the digital combination model and the theoretical topography obtained by geometric simulation method, the simulation topography of grinding surface can be generated. Moreover, the roughness parameters of the measured topography and the simulation topography under different machining parameters were compared. The maximum relative error of Sa, Sq, Ssk and Sku were 1.79%, 2.24%, 4.69% and 4.73%, respectively, which verifies the feasibility and accuracy of the presented method.

Image segmentation and robust edge detection for collision avoidance in machine tools

Collisions are a major cause of unplanned downtime in small series manufacturing with machine tools. Existing solutions based on geometric simulation do not cover collisions due to setup errors. Therefore a solution is developed to compare camera images of the setup with the simulation, thus detecting discrepancies. The comparison focuses on the product being manufactured (workpiece) and the fixture holding the workpiece, thus the first step consists in segmenting the corresponding region of interest in the image. Subsequently edge detection is applied to the image to extract the relevant contours. Additional processing steps in the spatial and frequency domain are used to alleviate effects of the harsh conditions in the machine, including swarf, fluids and sub-optimal illumination. The comparison of the processed images with the simulation will be presented in a future publication.

Geometric simulation for warp-knitted tubular bandages with the mesh model

The purpose of this paper is to geometrically simulate warp-knitted medical tubular bandages with a computer-aided simulator. A flat mesh model is established according to unfolded fabric considering the knitting characteristics of double-needle bed warp-knitted tubular fabrics. Moreover, a 3D (three-dimensional) mesh model corresponding to the actual product shape is created. To better describe the spatial geometry of stitches, eight-point models are introduced, and stitches are generated with the flat mesh model. Founded on matrix operations, the stitch position in the 3D mesh model is determined through coordinate mapping. Various stitch paths are rendered in computer programming languages C# and JavaScript to conduct simulations. Warp-knitted medical tubular bandages with a large number of shapes are effectively modeled.

Predictive Geometric Models for Heat-Insulation Properties of Semi-Finished Fur and Down Products

This paper is devoted to geometric simulation of heat-insulation properties of fur and down products which are considered as multi-parameter and multi-component systems. We consider predictive models of heat resistance depended on physical characteristics of fur and pelt. There is a problem of construction co-ordinate geometric models on condition that the set of experimental data is limited. We solve the problem as a problem for static multi-component systems. The model is considered as a piecewise constant function in the space of input and output parameters. The paper proposes an algorithm of construction the clusters on the set of given experimental points. Moreover, we construct multidimensional convex covering on the set of the points. The covering is based on its two-dimensional projections. Results of the investigations allow us to substantiate producer’s choice of fur and down semi-finished products and its composition for manufacturing the product of special purpose. The method suggested in the paper may be one of geometric modulus of the software HYPER-DESCENT which has been developed formerly. Our geometric models together with software HYPER- DESCENT may be applied for simulation and prediction the properties of another multi- parametrical systems or technological processes of light industry.

Using geometric simulation software ‘GASP’ to model conformational flexibility in a family of zinc metal-organic frameworks

Here, a new tripodal tricarboxylic acid ligand, 4,4'-(4'-(4'-carboxy-[1,1'-biphenyl]-4-yl)-[2,2':6',2''-terpyridine]-5,5''-diyl)-dibenzoic acid (H3cbt), was synthesised using a three-step convergent strategy. Subsequent reactions with zinc(II) nitrate hexahydrate yielded three metal-organic frameworks (MOFs). The three...

Geometry-Based Thick Origami Simulation

Origami is the art of creating a three-dimensional (3D) shape by folding paper. It has drawn much attention from researchers, and the designs that origami has inspired are used in various engineering applications. Most of these designs are based on familiar origami patterns and their known deformations, but origami patterns were originally intended for materials of near-zero thickness, primarily paper. To use the designs in engineering applications, it is necessary to simulate origami in a way that enables designers to explore and understand the designs while taking the thickness of the material to be folded into account. Because origami is primarily a problem in geometric design, this paper develops a geometric simulation for thick origami. The actuation, constraints, and assignment of mountain and valley folds in origami are also incorporated into the geometric formulation. The experimental results show that the proposed method is efficient and accurate. The method can successfully simulate a flat-foldable degree-four vertex, two different action origami, the bistable property of a waterbomb base, and the elasticity of non-rigid origami panels.