Rolling bearings - dynamic load ratings and rating life - life modification factor a ; amendment a2 iso 281 : 1990 amd 2 : 2000 滾動軸承.動載荷值和額定壽命.修改件2 :壽命改進(jìn)因子a
Rolling bearings - dynamic load ratings and rating life - life modification factor a and calculation of the modified rating life 滾動軸承.動力荷載額定值和額定壽命.壽命修改因素和
Current design codes of the steel structure ( gb50017 - 2003 ) gave the global stability coefficients of beams under loading of the concentrated load / the uniformly distributed load / the end moments , simultaneously offered its modification factors of the linearly distributed moment 現(xiàn)行國家鋼結(jié)構(gòu)設(shè)計規(guī)范( gb50017 - 2003 )給出了集中荷載,均布荷載,以及端彎矩作用下梁的整體穩(wěn)定系數(shù)。
Modification factors were given according to the relationship between elastic modulus reduction and tensile stress . the empirical elementarily formulas of damage evolution in tensile loading were given quantitatively , and verified by experiments 通過彈性模量衰減與應(yīng)力變化的關(guān)系,確定了二維編織、三維編織c sic復(fù)合材料拉伸損傷的修正系數(shù),初步定量給出了該材料拉伸損傷演化方程的經(jīng)驗公式并通過實驗驗證。
This paper , regarding the asphalt pavement in the zhoukou region as the study object , according to the prevalent norms ( specifications for design of highway asphalt pavement ) , with the beginning of the pavement performance and the transportation investigation , totally and systematically analyzes the traffic parameters and the destroying reason of pavement at the early stage in the point of fatigue property and limit strength , gives the concepts and methods of the growth rate of equivalent axle load action time , seasonal modification factor and overload factor , proposes the method of axle load conversion on the condition of heavy loading . on this basis , it proposes the design method adapting to asphalt pavement construction , explains the steps of thickness computation of construction with the combination of engineering example , finally verifies thedesign method in the paper by test road . theory and practice both prove that the reasonability of pavement structure style and the reliability of design method in the paper can adapt to the present heavy loading and overloading traffic conditions , have highly theoretical and practical value 本文以周口地區(qū)瀝青路面為研究對象,以現(xiàn)行《公路瀝青路面設(shè)計規(guī)范》為依據(jù),從路面使用性能和交通特征的調(diào)查入手,從疲勞特性和極限強(qiáng)度出發(fā)分析了路面早期破損的原因,全面系統(tǒng)地進(jìn)行了交通參數(shù)的分析,提出了當(dāng)量軸次增長率、季節(jié)修正系數(shù)和超載系數(shù)的概念和方法,并提出了重載交通的軸載換算方法。在此基礎(chǔ)上,針對超載、重載交通從結(jié)構(gòu)組合設(shè)計、結(jié)構(gòu)厚度計算(包括疲勞強(qiáng)度標(biāo)準(zhǔn)和極限強(qiáng)度標(biāo)準(zhǔn))等方面提出了適宜的瀝青路面結(jié)構(gòu)設(shè)計方法,并結(jié)合工程實測,說明了結(jié)構(gòu)層厚度計算的具體步驟,最后通過試驗路驗證本文提出的設(shè)計方法。理論與實踐均表明,本文提出的路面結(jié)構(gòu)型式合理、設(shè)計方法可靠,能適應(yīng)目前重載、超載交通的狀況,具有較高理論與實用價值。