Transverse Vibration Testing Research for 6.8 Grades Bolted Joint Used on Transmission Tower

2013 ◽  
Vol 470 ◽  
pp. 567-571
Author(s):  
Xiao Hao Dai ◽  
Yan Ting Feng ◽  
Xiao Guang Niu ◽  
Hui Fan ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Transverse Vibration ◽  
Decisive Role ◽  
Bolted Joint ◽  
Transmission Tower ◽  
Vibration Testing ◽  
Second Stage ◽  
Reduced Rate ◽  
Test Result

Five groups of vibration experiments were carried out on the 6.8 grades and M20 bolts and nuts that used on transmission tower. The test result shows that the basic way to improve the anti-loosening property was increasing the initial preload. Both increasing initial torque and appending lubrication can obviously increase the initial preload, however appending lubrication may reduce it's anti-loosening property under the situation of same preload. In the vibrating process the second stage plays a decisive role for anti-loosening property, it can be expressed as reduced rate “K” of the preload.

UPAYA MOTIVASI DAN AKTIVITAS BELAJAR IPA PADA MATERI PENGUKURAN DENGAN MENGGUNAKAN MEDIA ANIMASI FLASH DI SMP NEGERI 3 PERCUT SEI TUAN

2013 ◽  
Vol 2 (2) ◽  
pp. 25
Author(s):  
Untung Narpati
Keyword(s):  
Learning Activity ◽  
Seventh Grade ◽  
Average Percentage ◽  
Second Stage ◽  
Satisfaction Condition ◽  
Motivation And Learning ◽  
Academic Year ◽  
Test Result ◽  
Science Subject

This research is aimed to find out the efforts to raise students’motivation and learning activity by utilizing flash animation media on the Science subject on the topic discussion of “Pengukuran” to the seventh gradestudents of SMP Negeri 3 Percut Sei Tuan. The subjects of the research werethirty students of seventh grade Academic Year 2012/2013 that consist of 15males and 15 females. The object of the research was how to raise thestudents’ motivation and learning activity by utilizing flash animation mediabased on the STAD theory. The result reveals that: (1) there is an averagerise of the students’ learning completeness which is indicated by (a) the test result in the first stage completes 63.33%, (b) the test-result in the secondstage completes 86.70% and the index gain is 0.32% which raises mediumcriteria. (2) Students learning activity is found rose which is indicated by theincreasing average percentage of 72.40 in the first stage becomes 88.48 inthe second stage. (3) There is an increasing number of students learningmotivation which is known that students’ motivation in the attentioncondition rises as much as 28.44% from 52.89% in the first stage becomes81.33% in the second stage, there is an increasing number in the relevancecondition as much as 23.67% from 64.75% in the first stage becomes88.42% in the second stage, there is an increasing number in the confidencecondition as much as 30.86% from 57.71% in the first stage become 88.57%in the second stage, on the satisfaction condition; there is also increasingnumber as much as 23.58% from 65.33% in the first stage becomes 88.92%in the second stage.

Finite Element Modeling of Self-Loosening of Bolted Joints

2004 ◽  
Author(s):  
Ming Zhang ◽  
Yanyao Jiang ◽  
Chu-Hwa Lee
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Bending Moment ◽  
Shear Loading ◽  
Transverse Load ◽  
Fe Model ◽  
Bolted Joint ◽  
Cyclic Bending ◽  
Second Stage ◽  
Cyclic Bending Moment

A three-dimensional finite element (FE) model with the consideration of the helix angle of the threads was developed to simulate the second stage self-loosening of a bolted joint. The second stage self-loosening refers to the graduate reduction in clamping force due to the back-off of the nut. The simulations were conducted for two plates jointed by a bolt and a nut and the joint was subjected to transverse or shear loading. An M12×1.75 bolt was used. The application of the preload was simulated by using an orthogonal temperature expansion method. FE simulations were conducted for several loading conditions with different preloads and relative displacements between the two clamped plates. It was found that due to the application of the cyclic transverse load, micro-slip occurred between the contacting surfaces of the engaged threads of the bolt and the nut. In addition, a cyclic bending moment was introduced on the bolted joint. The cyclic bending moment resulted in an oscillation of the contact pressure on the contacting surfaces of the engaged threads. The micro-slip between the engaged threads and the variation of the contact pressure were identified to be the major mechanisms responsible for the self-loosening of a bolted joint. Simplified finite element models were developed that confirmed the mechanisms discovered. The major self-loosening behavior of a bolted joint can be properly reproduced with the FE model developed. The results obtained agree quantitatively with the experimental observations.

Finite Element Modeling of Self-Loosening of Bolted Joints

2006 ◽  
Vol 129 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Ming Zhang ◽  
Yanyao Jiang ◽  
Chu-Hwa Lee
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Bending Moment ◽  
Shear Loading ◽  
Transverse Load ◽  
Fe Model ◽  
Bolted Joint ◽  
Cyclic Bending ◽  
Second Stage ◽  
Cyclic Bending Moment

A three-dimensional finite element (FE) model with the consideration of the helix angle of the threads was developed to simulate the second stage self-loosening of a bolted joint. The second stage self-loosening refers to the gradual reduction in clamping force due to the back-off of the nut. The simulations were conducted for two plates jointed by a bolt and a nut and the joint was subjected to transverse or shear loading. An M12×1.75 bolt was used. The application of the preload was simulated by using an orthogonal temperature expansion method. FE simulations were conducted for several loading conditions with different preloads and relative displacements between the two clamped plates. It was found that due to the application of the cyclic transverse load, microslip occurred between the contacting surfaces of the engaged threads of the bolt and the nut. In addition, a cyclic bending moment was introduced on the bolted joint. The cyclic bending moment resulted in an oscillation of the contact pressure on the contacting surfaces of the engaged threads. The microslip between the engaged threads and the variation of the contact pressure were identified to be the major mechanisms responsible for the self-loosening of a bolted joint. Simplified finite element models were developed that confirmed the mechanisms discovered. The major self-loosening behavior of a bolted joint can be properly reproduced with the FE model developed. The results obtained agree quantitatively with the experimental observations.

Experiment Study on the Phenomenological Model of Bolted Joint Connections

2012 ◽  
Vol 193-194 ◽  
pp. 839-842
Author(s):  
Min Yang
Keyword(s):  
Experimental Study ◽  
Phenomenological Model ◽  
Bolted Joint ◽  
Phenomenological Method ◽  
Nonlinear Mechanics ◽  
Experiment Study ◽  
Joint Structure ◽  
Test Result

Based on phenomenological method, the paper carried out experimental study for a kind of typical bolted joint structure, three kinds of testing specimens was designed, from the test result, the phenomenological model was obtained and the nonlinear mechanics behavior was comprehended, at last, the phenomenological model was verified experimental and numerical

Theoretical and Experimental Research on Joint Slippage Effects of Lattice Angle Steel Tower

2013 ◽  
Vol 477-478 ◽  
pp. 660-665
Author(s):  
Zhang Qi Wang ◽  
Ze Ming Song ◽  
Wen Qiang Jiang
Keyword(s):  
Axial Force ◽  
Numerical Models ◽  
Element Model ◽  
Test Results ◽  
Bolted Joint ◽  
Transmission Tower ◽  
Hybrid Finite Element ◽  
Lattice Tower ◽  
Angle Steel ◽  
Bolt Diameter

In lattice angle steel transmission tower, as the bolt diameter is small and member connection is relatively thin, lower clamping force is commonly used in bolted joint. It is common in lattice tower during full tower tests, joint slippage occur even under design load. However, traditionally trussed beam hybrid finite element model without explicitly considering slippage effects has been widely used in the analysis of the tower. In this paper, the HD-1 tower was experimentally studied under various static load cases, and several numerical models with including joint eccentricity and slippage are established. After comparing the theoretical analysis results and the experimental results, the following conclusions are presented: joint eccentricity almost has not effects on leg member axial force; Among all the studied load cases, joint slippage effects the leg member force most under torsional condition than the other load conditions; Numerical model with including joint slippage effects yield much better axial force results in leg member compared with experimental test results.

scholarly journals PENGARUH PEMBERIAN KURMA TERHADAP KEMAJUAN PERSALINAN KALA II IBU BERSALIN DI RUMAH SAKIT AURA SYIFA KABUPATEN KEDIRI

2020 ◽  
Vol 2 (2) ◽  
pp. 126-134
Author(s):  
Lely Ayu Permata Addini ◽  
Ira Titisari ◽  
Ribut Eko Wijanti
Keyword(s):  
Date Palm ◽  
Sampling Technique ◽  
Fisher Exact Probability Test ◽  
Group Approach ◽  
Exact Probability ◽  
Second Stage Of Labor ◽  
Uterine Contractions ◽  
Second Stage ◽  
Static Group ◽  
Test Result

Progress of labor depends on three factors: (power) is the efficiency of uterine contractions, passenger (fetal) and passage (uterus, cervix, pelvis). When there are any abnormalities in one or more of the factors above it can slow the progress of delivery process. Dates rich in carbohydrates as a source of energy, affect the progress of labor, spontaneity in labor and reduce postpartum hemorrhage. Carbohydrates as a booster are sugars that are absorbed and used by body cells not long after consumed. The purpose of this study was to determine the effect of dates on the progress of the second stage of labor in Aura Syifa Hospital Kediri Regency. The research design used was pre-experimental (pre experimental design) with a static group approach (the static group comparison). The samples were 32 respondents who were determined by accidental sampling technique. In this research the data analysis used was Fisher Exact Probability test. Based on the statistic test result that there was no influence of Providing Date Palm to the mother in labor at second progress of labor in Kediri Aura Syifa Hospital.

Fatigue Characteristics of Bolted Joint under Transverse Vibration ~Influence of Bolt Tightening Conditions on Transverse Fatigue Strength~

2010 ◽  
Vol 452-453 ◽  
pp. 609-612
Author(s):  
Shinji Hashimura ◽  
YU Kurakake ◽  
Shinichi Umeno
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Transverse Vibration ◽  
Bending Moment ◽  
Fatigue Tests ◽  
Bolted Joint ◽  
The Real ◽  
Thread Length ◽  
Fatigue Characteristics

Fatigue tests under transverse vibration were performed for three separate tightening conditions to investigate the grip length and the engaging thread length in this study. The relationships between the apparent fatigue limit (the highest amplitude of transverse vibration force which can be applied to the bolted joint without generating fatigue) and the real fatigue limit of bolt material also were investigated. Results showed that apparent transverse fatigue limit decreased if the grip length was long. And relationships of the apparent fatigue limit and the real fatigue limit were different in each tightening conditions depending on the bending moment at the root of the first thread.

scholarly journals Design and Experimental Study of Potato-Soil SeparationDevice for Sticky Soils Condition

2021 ◽  
Vol 11 (22) ◽  
pp. 10959
Author(s):  
Bei Wu ◽  
Tianci Huang ◽  
Xuanxuan Qiu ◽  
Tianlin Zuo ◽  
Xiushan Wang ◽  
...  
Keyword(s):  
Potato Tuber ◽  
Field Experiments ◽  
Southern China ◽  
Orthogonal Test ◽  
National Standard ◽  
Separation Device ◽  
Second Stage ◽  
Damage Rate ◽  
Harvesting Process ◽  
Test Result

The potato-soil separation device comprising five function areas (i.e., shearing, bending, throwing, cleaning, and conveying) was developed to address the mentioned problems (e.g., soil with high moisture content, large viscosity, and poor separation efficacy) in the harvesting process for winter idle paddy fields of Southern China. Given the kinetic analyses for the potato-soil mixture of five function areas, the crucial factors of the effect of potato-soil separation were determined. Subsequently, the orthogonal test of 4 factors and 3 levels was performed, and the percentage of small soil λ, the percentage of soil adhering to potato tuber γ, and damage rate of potato tuber K were adopted as assessment indexes. Regression analyses and programming for the orthogonal test result were conducted to optimize the device run parameters, and the optimal run parameters included the rotational speed of the soil-crushing mechanism of 84.18 r/min, linear velocity of second-stage lifting chain of 0.75 m/s, and inclination angle of lifting chain of 15.87°. The field experiments were performed with the modified potato harvester. As indicated from the result, the visible potato rate was 94.31% and damage rate of potato was 0.89%, and the requirement of the national standard was satisfied. This study presented technical feasibility data and equipment for potato-soil separation under sticky soils condition.

scholarly journals Statistical methods for batch screening of input populations by stage and group in COVID-19 nucleic acid testing

2020 ◽  
Author(s):  
Cheng Yuan Yuan
Keyword(s):  
Nucleic Acid ◽  
High Risk ◽  
Sample Size ◽  
Nasopharyngeal Swab ◽  
Nucleic Acid Testing ◽  
Test Results ◽  
Risk Of Infection ◽  
Positive Group ◽  
Second Stage ◽  
Test Result

AbstractPurposeTo screen for COVID-19 patients in immigration using minimal nucleic acid testing (NAT).MethodsIn the first phase, nasopharyngeal swab samples from the inbound population were numbered and grouped. The samples in the group were mixed together, and a NAT test was performed. When the test result is negative, it means that everyone in the group is not infected and the screening of the group is complete. When the test results were positive, the group moved on to the second stage. In the second stage, all samples in the positive group will be tested individually for NAT.ResultsThe advantages and considerations of the method are discussed. Prevalence in the incoming population was a determinant of the sample size within the group. The lower the incidence, the larger the sample size within the group, the higher the savings in NAT and testing costs.ConclusionThis method has significant efficiency and cost advantages in COVID-19 screening. It can also be used to screen other populations, such as community populations and people at high risk of infection, etc.

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