Experimental Research on the Stiffness of Hyperboloid Shallow Shell

2014 ◽  
Vol 940 ◽  
pp. 179-183
Author(s):  
Li Hong Zhao ◽  
Cheng Xi Lei ◽  
Zhong Wen Xing ◽  
Bin Wu
Keyword(s):  
High Strength ◽  
Process Conditions ◽  
Main Process ◽  
Technical Approach ◽  
Shallow Shells ◽  
Process Guidance ◽  
Experiment Method ◽  
Automobile Panel ◽  
Blank Holding Force ◽  
Panel Stiffness

Stiffness is a very important property of automobile panel, especially for high-strength thinning sheet due to personnel security and energy conservation on auto industry. It is difficult to study because of the complexity streamline feature of auto body. An experiment method for determining stiffness was presented. The experiment study models of which based on the hyperboloid shallow shells that could represent automobile panel’s surface features was established. The criterion and research technique of automobile panel stiffness were introduced. The experiment research works of effects of two main process conditions on stiffness which blank holding force (BHF) and boundary condition during the stiffness test were obtained. All conclusions provided a particularly effective process guidance and technical approach in the automobile panel production.

scholarly journals Parametric Investigation of Effect of Abnormal Process Conditions on Self-Piercing Riveting

2020 ◽  
Vol 10 (7) ◽  
pp. 2520 ◽  
Author(s):  
Taek-Eon Jeong ◽  
Dong-Hyuck Kam ◽  
Cheolhee Kim
Keyword(s):  
Process Parameters ◽  
Dissimilar Materials ◽  
High Strength ◽  
Process Conditions ◽  
Al Alloy ◽  
Main Process ◽  
Cross Sectional ◽  
Practical Applications ◽  
Parametric Investigation ◽  
Offset Distance

Self-piercing riveting (SPR) is one of the mechanical joining processes, and its application to Al/Fe dissimilar materials combination, which is hard to weld, is expanding in the automotive industry. The main process parameters in SPR are types of rivet and die, setting force, and rivet setting speed. Previously, the relationship between the main process parameters and output parameters such as cross-sectional characteristics and joint strength has been studied to optimize the SPR process. In practical applications, there are unexpected and abnormal process conditions such as poor fit-up, angular misalignment, edge offset distance, and inaccurate setting and pre-clamping forces, and their effects on the joining quality have not been discussed. In this study, parametric investigation was performed using an experimental design on SPR joints for 1 mm-thick high strength steel (590 DP) and 2 mm-thick Al alloy (Al5052-H32). The main effect of each level of the abnormal process parameters on the output parameters was statistically investigated, and the analysis of variance was performed for each abnormal process parameter. In the range of abnormal process conditions applied, the set force was the most significant factor affecting the output parameters, and the effect of pre-clamping force on the output parameters was the least significant.

Experimental Research on Impact Line of Hyperboloid Shallow Shell

2010 ◽  
Vol 139-141 ◽  
pp. 567-570
Author(s):  
Li Hong Zhao ◽  
Zheng Yi Ren ◽  
Shu Yong Jiang ◽  
Nan Yang
Keyword(s):  
Process Conditions ◽  
Forming Process ◽  
Shape Accuracy ◽  
Test Analysis ◽  
Shallow Shells ◽  
Blank Holding Force ◽  
Auto Body ◽  
Design And Manufacture ◽  
The Impact

Impact line is one of important factors to affect the shape accuracy and surface quality of auto body panel design and manufacture. It is difficult to study because of the complexity shape of auto body panels. The system of test analysis on impact line is established by analyzing the shapes and forming processes of auto-body panels, of which based on hyperboloid shallow shells. The criterion and research technique of impact line are introduced. Extensive experiment results, which show the effects of forming process conditions, such as blank holding force, draw bead arrangement, and lubrication on impact line, are achieved. It can be concluded that the draw bead arrangement significantly influence the impact line, the displacement of impact line is different with difference of blank holding force and the friction coefficient.

Influence of Die Materials on the Microstructural Evolution of HSS Sheets in Hot Stamping

2011 ◽  
Vol 473 ◽  
pp. 201-208 ◽  
Author(s):  
Andrea Ghiotti ◽  
Stefania Bruschi ◽  
Daniele Pellegrini
Keyword(s):  
Hot Stamping ◽  
Sheet Thickness ◽  
High Strength Steels ◽  
High Strength ◽  
Process Conditions ◽  
Main Process ◽  
Metal Sheets ◽  
Die Materials ◽  
Set Up ◽  
Tools Wear

Hot stamping of High Strength Steels sheets is gaining more and more popularity, particularly in the automotive industry, due to the sound microstructures achieved at the end of the process. The significant improvement of the mechanical properties achieved in the process enables to reduce the initial sheet thickness in favour of cost and fuel consumption reduction. However, a martensitic microstructure implies significant drawbacks in final trimming and cutting operations, which becomes more difficult and expensive due to tools wear and high blanking forces. This paper aims at investigating the performances of non-metallic materials to be used in heated dies, in order to inhibit the martensite formation by locally reducing the sheet cooling rate. To analyze the influence of the main process parameters, a new experimental set-up was designed and developed in a laboratory environment that allow applying controlled pressure and temperatures to HSS metal sheets. An analytical model was set-up in order to evaluate the influence of process conditions on the cooling profiles in different areas of the specimen. Accordingly, experiments were carried out to investigate the material behaviour when cooled in the different conditions. The experimentally acquired temperatures were analyzed and evaluated together with hardness measurements of metal sheets in order to assess the feasibility of the proposed approach in producing microstructurally-tailored components.

CHEMICAL PULPING. Oxidative degradation of AOX in softwood-based kraft mill effluents from E C F bleachin g

2012 ◽  
Vol 27 (4) ◽  
pp. 707-713 ◽  
Author(s):  
Jukka Pekka lsoaho ◽  
Suvi Tarkkanen ◽  
Raimo Alen ◽  
Juha Fiskari
Keyword(s):  
Reaction Time ◽  
Oxidative Degradation ◽  
Cost Effective ◽  
Process Conditions ◽  
Main Process ◽  
Chemical Pulping ◽  
Kraft Mill ◽  
Organic Halogens ◽  
Aox Removal ◽  
Adsorbable Organic Halogens

Abstract Softwood-based kraft mill bleaching effluents from the initial bleaching stages D0 and E1 (the bleaching sequence being D0E 1D 1 E2D2) were treated by the oxidative Fenton method (H20rFeS04) to decompose organic pollutants contammg adsorbable organic halogens (AOX). Experiments designed using the Taguchi method were applied to predict the process conditions that would result in a cost-effective and adequate removal of AOX. In addition to the composition and concentration of the reagents (H202 and Fe2+), the main process parameters selected were temperature and reaction time, while pH was adj usted to an approximate value of 4 (the volumetric ratio of the mixed effluents D0:E 1 was 3 :2). The results indicated that an AOX removal of about 70% for this mixture ( corresponding to about 50% for the mill) was achieved when the eftluent samples were treated for 60 min at 70°C with H202 and Fe2+ at a concentration of 1 600 mg/1 and 28 mg/1, respectively.

Low-consistency refining of CTMP targeting high strength and bulk: effect of filling pattern and trial scale

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jan-Erik Berg ◽  
Börje Hellstadius ◽  
Mikael Lundfors ◽  
Per Engstrand
Keyword(s):  
High Strength ◽  
Natural Fibre ◽  
Laboratory Scale ◽  
Process Conditions ◽  
Tensile Index ◽  
Filling Pattern ◽  
Basic Objective ◽  
High Bulk ◽  
Fibre Morphology ◽  
Bulk Effect

AbstractChemithermomechanical pulp (CTMP) is often used in central layers of multiply paperboards due to its high bulk and strength. Such a CTMP should consist of well-separated undamaged fibres with sufficient bonding capacity. The basic objective of this work is to optimize process conditions in low-consistency (LC) refining, i. e. to select or ultimately develop new optimal LC refiner filling patterns, in order to produce fibrillar fines and improve the separation of fibres from each other while preserving the natural fibre morphology as much as possible. Furthermore, the aim is to evaluate if this type of work can be done at laboratory-scale or if it is necessary to run trials in pilot- or mill-scale in order to get relevant answers. First stage CTMP made from Norway spruce (Picea abies) was LC refined in mill-, pilot- and laboratory-scale trials and with different filling patterns. The results show that an LR1 laboratory refiner can favourably be used instead of larger refiners in order to characterize CTMP with regard to tensile index and z-strength versus bulk. A fine filling pattern resulted in CTMP with higher tensile index, z-strength and energy efficiency at maintained bulk compared to a standard filling pattern.

Experimental Study of Forming Rene95 Alloy Parts by Laser Cladding

2001 ◽  
Author(s):  
Qilin Deng ◽  
Dejin Hu ◽  
Jingyu Pei ◽  
Wenwu Zhang ◽  
Y. Lawrence Yao
Keyword(s):  
Experimental Study ◽  
Laser Cladding ◽  
Laser Power ◽  
Alloy Powder ◽  
High Strength ◽  
Scanning Speed ◽  
Main Process ◽  
Beam Diameter ◽  
Laser Beam Diameter ◽  
Metal Parts

Abstract In this paper, experimental study of forming metal parts by laser cladding Rene95 alloy powder was reported. The influence of main process parameters, such as laser power, scanning speed and laser beam diameter, on the thickness, width and the angle of the laser cladding track was investigated. The microstructures of laser cladding parts were studied and compared with those of common casting parts. The obtained Rene95 metal parts formed by laser cladding are dense and of high strength.

scholarly journals Conduction-Based Thermally Assisted Micromilling Process for Cutting Difficult-to-Machine Materials

2020 ◽  
Vol 4 (2) ◽  
pp. 34 ◽  
Author(s):  
Timo Platt ◽  
Alexander Meijer ◽  
Dirk Biermann
Keyword(s):  
Tool Wear ◽  
High Speed ◽  
End Milling ◽  
High Speed Steel ◽  
High Strength ◽  
Process Conditions ◽  
Manufacturing Processes ◽  
Central Process ◽  
Workpiece Temperature ◽  
Micro End Milling

The increasing demand for complex and wear-resistant forming tools made of difficult-to-machine materials requires efficient manufacturing processes. In terms of high-strength materials; highly suitable processes such as micromilling are limited in their potential due to the increased tool loads and the resulting tool wear. This promotes hybrid manufacturing processes that offer approaches to increase the performance. In this paper; conduction-based thermally assisted micromilling using a prototype device to homogeneously heat the entire workpiece is investigated. By varying the workpiece temperature by 20 °C < TW < 500 °C; a highly durable high-speed steel (HSS) AISI M3:2 (63 HRC) and a hot-work steel (HWS) AISI H11 (53 HRC) were machined using PVD-TiAlN coated micro-end milling tools (d = 1 mm). The influence of the workpiece temperature on central process conditions; such as tool wear and achievable surface quality; are determined. As expected; the temporary thermal softening of the materials leads to a reduction in the cutting forces and; thus; in the resulting tool wear for specific configurations of the thermal assistance. While only minor effects are detected regarding the surface topography; a significant reduction in the burr height is achieved.

Reach on Impact Line of Hyperboloid Shallow Shell Surface Deflection

2009 ◽  
Vol 628-629 ◽  
pp. 511-516 ◽  
Author(s):  
Li Hong Zhao ◽  
Y.F. Zheng ◽  
Zhong Wen Xing
Keyword(s):  
Finite Element ◽  
Sheet Thickness ◽  
Test Method ◽  
Element Analysis ◽  
Shallow Shells ◽  
Blank Holding Force ◽  
Simulation And Experiment ◽  
Auto Body ◽  
Automotive Panels ◽  
The Impact

The impact line is a remarkable disadvantage in the auto body panels forming. It is difficult to study because of the complexity shape of automotive panels. The finite element models of hyperboloid shallow shells that can represent automotive panels are established, and suitability of finite element analysis to induce the impact line of automotive panel is carried out. The experiment test method for determining impact line is presented also. The criterion and research technique of auto body panels impact line are introduced. The consistency of results of simulation and experiment shows that the numerical simulation on research of impact line is accurate and feasible. Finally, research works of simulation and experiment on controlling impact line measures are carried out: effects of blank holding force (BHF), sheet thickness and lubricating modes on the impact line are obtained.

Press-Shaving Characteristics of Ultrahigh-Strength Steel Sheets

2013 ◽  
Vol 554-557 ◽  
pp. 1879-1886 ◽  
Author(s):  
Masao Murakawa ◽  
Kenta Nakamura ◽  
Tomio Shionome ◽  
Fumitoshi Komuro ◽  
Giichirou Muro ◽  
...  
Keyword(s):  
Surface Quality ◽  
New Technologies ◽  
High Strength ◽  
Process Conditions ◽  
Steel Sheets ◽  
Ultrahigh Strength ◽  
Ultrahigh Strength Steel ◽  
Experimental Researches ◽  
Very High

The paper proposes new technologies able to improve the surface quality in the case of press-shaving applied to very high strength materials. Experimental researches were developed and the best combination of process conditions was identified.

scholarly journals Numerical Modelling of the Powder Metallurgical Manufacturing Chain of High Strength Sintered Gears

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Ali Rajaei ◽  
Yuanbin Deng ◽  
Oliver Schenk ◽  
Soheil Rooein ◽  
Alexander Bezold ◽  
...  
Keyword(s):  
High Performance ◽  
Monte Carlo Model ◽  
High Strength ◽  
Homogenization Method ◽  
Process Conditions ◽  
Fe Modelling ◽  
Production Chain ◽  
Materials Engineering ◽  
Integrated Computational Materials Engineering ◽  
Computational Materials

AbstractThis paper presents a digital model for the powder metallurgical (PM) production chain of high-performance sintered gears based on an integrated computational materials engineering (ICME) platform. Discrete and finite element methods (DEM and FEM) were combined to describe the macroscopic material response to the thermomechanical loads and process conditions during the entire production process. The microstructural evolution during the sintering process was predicted on the meso-scale using a Monte-Carlo Model. The effective elastic properties were determined by a homogenization method based on modelling a representative volume element (RVE). The results were subsequently used for the FE modelling of the heat treatment process. Through the development of multi-scale models, it was possible obtain characteristics of the microstructural features. The predicted hardness and residual stress distributions allowed the calculation of the tooth root load bearing capacity of the heat-treated sintered gears.

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