scholarly journals Research on the precision loss of ball screw with short-time overload impact

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881790 ◽  
Author(s):  
Jiajia Zhao ◽  
Mingxing Lin ◽  
Xianchun Song ◽  
Hongkui Jiang
Keyword(s):  
Plastic Deformation ◽  
Load Condition ◽  
Ball Screw ◽  
Axial Deformation ◽  
Elastic Plastic ◽  
Precision Equipment ◽  
Model Combining ◽  
High Load Condition ◽  
Short Time ◽  
The Relationship

Ball screw is the driving functional component most frequently used for the precision equipment. To a certain extent, the transmission accuracy of precision equipment is affected by the position error of ball screw caused by the elastic–plastic deformation between ball and raceway under the overload impact. This article aims to investigate the precision loss of ball screw considering short-time overload impact. A novel precision loss model combining the Hertzian and Thornton contact theories is established to describe the variations in the axial deformation depths. Thus, the axial precision loss can be defined as the differential value between the initial no-loading travel variations and the loading stroke variations caused by the axial plastic deformation of raceway. Meanwhile, the maximum stress and the residual plastic deformation for four couples of ball-raceway materials are analyzed. Furthermore, the relationship between the precision loss and the elastic–plastic deformation is studied by the theoretical analysis and experiments. The results show that the position and precision is affected indeed by the contact deformation. The position and precision loss of the nut relative to the screw increases with the increase in the axial load. The results can help to provide the prediction for the precision life of ball screw operating in high-load condition.

Validation on the Relationship Between J Integral and CTOD for Offshore Structural Steel Weldments by Experimental and Numerical Analyses

2014 ◽  
Author(s):  
Dong Hyun Moon ◽  
Jeong Soo Lee ◽  
Jae Myung Lee ◽  
Myung Hyun Kim
Keyword(s):  
Plastic Deformation ◽  
Crack Tip ◽  
J Integral ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Constraint Factor ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Plastic Constraint ◽  
The Relationship

Elastic plastic fracture mechanics (EPFM) is the domain of fracture analysis which considers extensive plastic deformation at crack tip prior to fracture. J integral and crack tip opening displacement (CTOD) have been commonly used as parameters for EPFM analysis. The relationship between these parameters has been extensively studied by industry and academia. The plastic constraint factor can serve as a parameter to characterize constraint effects in fracture involving plastic deformation. Therefore, the characteristics of plastic constraint factor are important in EPFM analysis. In this study, the relationship between J Integral and CTOD was investigated by conducting fracture toughness tests using single edge notched bend (SENB) specimens. Also, plastic constraint factor was investigated by using finite element analysis. Numerical analysis was carried out using ABAQUS elastic-plastic analysis mode.

Analysis of the precision sustainability of the preload double-nut ball screw with consideration of the raceway wear

2019 ◽  
Vol 234 (9) ◽  
pp. 1530-1546 ◽  
Author(s):  
Jiajia Zhao ◽  
Mingxing Lin ◽  
Xianchun Song ◽  
Qizhen Guo
Keyword(s):  
Test Bench ◽  
Interpolation Method ◽  
Ball Screw ◽  
Machining Accuracy ◽  
Wear Depth ◽  
Wear Model ◽  
Coupling Relationship ◽  
Precision Equipment ◽  
Model Combining ◽  
Iterative Interpolation

Ball screws are the driving components used to convert the rotational motion into linear motion in precision equipment. However, the machining accuracy of precision equipment is directly determined by the positioning accuracy of the ball screw. The authors analyze the precision sustainability of preload double-nut ball screws with raceway wear. A new wear model combining the modified Archard theory and the iterative interpolation method is established to analyze the variations in wear depth. A new model considering the coupling relationship between raceway wear and preload loss is proposed to study the precision life of the double-nut ball screw. In addition, a novel running test bench is designed to verify the precision sustainability of ball screws. The precision sustainability of the ball screw is analyzed during its life cycle, and these results match the theoretical values obtained by using the wear model.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals Application of an Innovative Model for the Risk Management of COVID-19 in a Multinational Manufacturing Company

2021 ◽  
Vol 13 (11) ◽  
pp. 5771
Author(s):  
Piero Lovreglio ◽  
Angela Stufano ◽  
Francesco Cagnazzo ◽  
Nicola Bartolomeo ◽  
Ivo Iavicoli
Keyword(s):  
Risk Management ◽  
Manufacturing Industry ◽  
Incidence Rates ◽  
Manufacturing Plants ◽  
Model Combining ◽  
Innovative Model ◽  
Global Prevention ◽  
The Relationship ◽  
Physician Team ◽  
The Eu

The COVID-19 incidence in 61 manufacturing plants in Europe (EU), North America (NA) and Latin-America (LATAM) was compared with the incidence observed in the countries where the plants are located in order to evaluate the application of an innovative model for COVID-19 risk management. Firstly, a network of local and global teams was created, including an external university occupational physician team for scientific support. In July 2020, global prevention guidelines for the homogenous management of the pandemic were applied, replacing different site or regional procedures. A tool for COVID-19 monitoring was implemented to investigate the relationship between the incidence rates inside and outside the plants. In the period of May–November 2020, 565 confirmed cases (EU 330, NA 141, LATAM 94) were observed among 20,646 workers with different jobs and tasks, and in the last two months 85% EU and 70% NA cases were recorded. Only in 10% of cases was a possible internal origin of the contagion not excluded. In the EU and NA, unlike LATAM, the COVID-19 incidence rates inside the sites punctually followed the rising trend outside. In conclusion, the model, combining a global approach with the local application of the measures, maintains the sustainability in the manufacturing industry.

Energy storage and dissipation of elastic-plastic deformation under shock compression: Simulation and Analysis

2021 ◽  
Vol 158 ◽  
pp. 103876
Author(s):  
Qi-lin Xiong ◽  
Zhenhuan Li ◽  
Takahiro Shimada ◽  
Takayuki Kitamura
Keyword(s):  
Plastic Deformation ◽  
Energy Storage ◽  
Shock Compression ◽  
Elastic Plastic

scholarly journals The Effects of Extraneous Load on the Relationship Between Self-Regulated Effort and Germane Load Within an E-Learning Environment

2017 ◽  
Vol 18 (5) ◽  
Author(s):  
Christopher Lange ◽  
Jamie Costley ◽  
Seung-Lock Han
Keyword(s):  
Load Condition ◽  
Poor Quality ◽  
Online Instructors ◽  
South Korean ◽  
Processing Information ◽  
E Learning ◽  
Effort Regulation ◽  
Extraneous Load ◽  
Survey Responses ◽  
The Relationship

<p class="3">Online instructors need to avoid unclear and confusing explanations of content, which can reduce the quality of learning. Extraneous load is reflective of poor instruction, in that it directs student effort towards processing information that does not contribute to learning. However, students may be able to manage poor instruction through effort regulation. Students who show high levels of effort have been shown to overcome poor instruction in some cases. This study analyzed survey responses from South Korean university students studying online (n = 1,575) to examine the relationship between self-regulated effort and germane load within varying extraneous load conditions. The experimental design separated extraneous load responses into three conditions (low, medium, high). Within each extraneous load condition, self-regulated effort responses were also separated (low, medium, high). The results showed that as extraneous load increased, self-regulated effort had a weaker relationship with germane load. It was also found that the use of effort regulation is effective only when dealing with low and mid-level extraneous load situations and that use of such strategies within high extraneous load situations was not effective. These results show the importance of improving instruction to reduce extraneous cognitive load, in that, not even high levels of effort can overcome poor quality instruction.</p>

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