Research on the Collision Checking During the Boosters-Separation Based on Spatial Geometry Structure

2021 ◽  
Author(s):  
Wu Jie ◽  
He Wei ◽  
Feng Shaowei ◽  
Liu Yang ◽  
Huo Mingying ◽  
...  
Keyword(s):  
Geometry Structure ◽  
Spatial Geometry

scholarly journals Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

2021 ◽  
Vol 9 (3) ◽  
pp. 256
Author(s):  
Wei Liu ◽  
Hao Tang ◽  
Xinxing You ◽  
Shuchuang Dong ◽  
Liuxiong Xu ◽  
...  
Keyword(s):  
Drag Force ◽  
Mesh Size ◽  
Current Speed ◽  
Midwater Trawl ◽  
Minimum Drag ◽  
Fish Catch ◽  
Spatial Geometry ◽  
By Catch ◽  
Trawl Fisheries ◽  
Crucial Part

The codend of a trawl net is the rearmost and crucial part of the net for selective fish catch and juvenile escape. To ensure efficient and sustainable midwater trawl fisheries, it is essential to better understand the drag characteristics and fluttering motions of a midwater trawl codend. These are generally affected by catch, cutting ratio, mesh size, and twine diameter. In this study, six nylon codend models with different cutting ratios (no cutting, 6:1, 5:1, 4:1, 7:2, and 3:1) were designed and tested in a professional flume tank under two conditions (empty codends and codends with catch) and five current speeds to obtain the drag force, spatial geometry, and movement trend. As the cutting ratio of empty codends decreased, the drag force decreased, and the drag coefficient increased. The unfolding degree of codend netting and the height of empty codends were found to be directly proportional to the current speed and inversely proportional to the cutting ratio. The positional amplitude of codend with cutting ratio 4:1 was the smallest for catch. The drag force of codends with catch increased as the current speed increased, and first decreased and then increased as the cutting ratio decreased. To ensure the best stability and minimum drag force of the codend, it is recommended to use the 4:1 cutting ratio codend.

scholarly journals Vibroacoustic Assessment of an Innovative Composite Material for the Roof of a Coupe Car

2021 ◽  
Vol 11 (3) ◽  
pp. 1128
Author(s):  
Nunziante Cascone ◽  
Luca Caivano ◽  
Giuseppe D’Errico ◽  
Roberto Citarella
Keyword(s):  
Composite Material ◽  
Transfer Functions ◽  
Realistic Model ◽  
Point Of View ◽  
Damping Capacity ◽  
Geometry Structure ◽  
Fiberglass Composite ◽  
New Material ◽  
Static Rigidity ◽  
Innovative Material

The objective of this paper is the vibroacoustic evaluation of an innovative material for a sports car roof, aiming at replacing fiberglass composite materials. Such evaluation was carried out using numerical and experimental analysis techniques, with cross-comparison between the corresponding results. The innovative material under analysis is a composite material, with a thermoplastic polypropylene matrix and reinforcement made of cellulose fibers. In order to validate the virtual dynamic modeling of the new material, the inertance on different points of some sheets made of the material under analysis was evaluated by an in-house made experimental activity, performed in the CRF (Fiat Research Center) test room, and cross-compared with corresponding results from a numerical analysis performed with the MSC Nastran software. Then, a realistic model of the car roof of the Alfa Romeo 4C car, made with the new material, was implemented and analyzed from the vibroacoustic point of view. The mere switch to the new material, with no changes in the geometry/structure of the car roof, did not allow preserving the original values of static rigidity, dynamic rigidity, and configuration of modal shapes. For this reason, a geometric/structural optimization of the component was performed. Once the new geometry/structure was defined, a vibroacoustic analysis was carried out, checking for a possible coupling between the fluid cavity modes and the structure car body modes. Finally, the vibroacoustic transfer functions to the driver’s ear node were assessed, considering two different excitation points on the structure. The excellent damping capacity of the proposed material led to an improvement in the vibroacoustic transfer functions and to a reduction in the weight of the pavilion.

scholarly journals Dynamic multistep uncertainty prediction in spatial geometry

Procedia CIRP ◽  
2021 ◽  
Vol 96 ◽  
pp. 74-79
Author(s):  
Alex Grenyer ◽  
Oliver Schwabe ◽  
John A. Erkoyuncu ◽  
Yifan Zhao
Keyword(s):  
Uncertainty Prediction ◽  
Spatial Geometry

INFLUENCE OF GENDER ON LEFT VENTRICULAR GEOMETRY (STRUCTURE) AND FUNCTION IN ISOLATED SYSTOLIC ARTERIAL HYPERTENSION

2011 ◽  
Vol 22 ◽  
pp. S40
Author(s):  
Dafni Koumoutsea ◽  
Stavros Chrisanthopoulos ◽  
Vasilios German ◽  
Pantelis Kapralos ◽  
Damianos Aslanoglou ◽  
...  
Keyword(s):  
Arterial Hypertension ◽  
Left Ventricular ◽  
Structure And Function ◽  
Left Ventricular Geometry ◽  
Ventricular Geometry ◽  
Geometry Structure ◽  
And Function

Presenting a Railbound Forging Manipulator

2015 ◽  
Vol 762 ◽  
pp. 219-224
Author(s):  
Florian Ion Petrescu ◽  
Relly Victoria Petrescu
Keyword(s):  
Main Mechanism ◽  
Kinematic Scheme ◽  
Large Load ◽  
Geometry Structure ◽  
Operation Process ◽  
Walking Motion ◽  
Capacitive Load ◽  
Forging Manipulator ◽  
Output Characteristics ◽  
General Aspects

Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationships between outputs and inputs have greatly influence about the control and the reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper one presents the general aspects of a railbound forging manipulator, like geometry, structure, general kinematics and forces of the main mechanism from such manipulator. Kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed.

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

2021 ◽  
pp. 004051752110138
Author(s):  
Haisang Liu ◽  
Gaoming Jiang ◽  
Zhijia Dong
Keyword(s):  
Programming Languages ◽  
Three Dimensional ◽  
3D Mesh ◽  
Mesh Model ◽  
Matrix Operations ◽  
Computer Aided ◽  
Spatial Geometry ◽  
3D Mesh Model ◽  
Coordinate Mapping ◽  
Geometric Simulation

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.

Sign in / Sign up

Export Citation Format

Share Document