欢迎来到麦多课文档分享! | 帮助中心 海量文档,免费浏览,给你所需,享你所想!
麦多课文档分享
全部分类
  • 标准规范>
  • 教学课件>
  • 考试资料>
  • 办公文档>
  • 学术论文>
  • 行业资料>
  • 易语言源码>
  • ImageVerifierCode 换一换
    首页 麦多课文档分享 > 资源分类 > PDF文档下载
    分享到微信 分享到微博 分享到QQ空间

    NASA-TN-D-1584-1964 Evaluation of the influence of load randomization and of ground-air-ground cycles on fatigue life《荷载随机化和地空循环对疲劳寿命的影响评估》.pdf

    • 资源ID:836781       资源大小:605.83KB        全文页数:38页
    • 资源格式: PDF        下载积分:10000积分
    快捷下载 游客一键下载
    账号登录下载
    微信登录下载
    二维码
    微信扫一扫登录
    下载资源需要10000积分(如需开发票,请勿充值!)
    邮箱/手机:
    温馨提示:
    如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
    如需开发票,请勿充值!如填写123,账号就是123,密码也是123。
    支付方式: 支付宝扫码支付    微信扫码支付   
    验证码:   换一换

    加入VIP,交流精品资源
     
    账号:
    密码:
    验证码:   换一换
      忘记密码?
        
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,就可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰。
    5、试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。

    NASA-TN-D-1584-1964 Evaluation of the influence of load randomization and of ground-air-ground cycles on fatigue life《荷载随机化和地空循环对疲劳寿命的影响评估》.pdf

    1、- NASA TECHNICAL NOTE d 00 Ih c I n z NASA TN D-1584-ii I EVALUATION OF THE INFLUENCE OF LOAD RANDOMIZATION AND OF GROUND-AIR-GROUND CYCLES ON FATIGUE LIFE by Eugene C. Naumann Langley Research Center Langley Station, Hampton, Va. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. OCTOB

    2、ER 1964 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ERRATA NASA Technical Note D-1584 EVALUATION OF THE IIWLUENCE OF LOAD RANDOMIZATION AND OF GROUND-AIR-GROUND CYCUS ON FATIGUE LIJQ By Eugene C. Nau“ y I- October 1964 (?,. I l*i /,? 6 L-, -I? ap

    3、proximately 2:l and 1.25:l were obtained, respectively. Sufficient data are not available to establish reliable relationships between GAG cycle spacing and life. From this it appears that the number of gust cycles used to represent typical flight directly influences the results obtained when the num

    4、ber of flights simulated is used as the basis of comparison. Thus, the life obtained in fatigue-evaluation tests can be very misleading if the anticipated service load history is appreciably different from the actual service load history. CONCLUSIONS 0 The results of variable-amplitude axial-load fa

    5、tigue tests on edge notched spechens with loads programed to approximate a gust-load spectrum support the following conclusions: 1. The insertion of ground-air-ground cycles (GAG) produced a large decrease in the number of simulated flights when compared with similar tests without the ground-air-gro

    6、und cycle. The.numberof flights simulated was found to be influenced as indicated by the following conditions: (a) GAG cycle range -number of flights decreased as GAG range increased the change is much Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-

    7、greater than anticipated by 1n/N) and (b) degree of load randomization - the decrease in number of flights was greater in random tests than in block tests having GAG cycles with the same range. 2. Ground-air-ground cycle spacing has a definite influence on the fatigue life as measured by the number

    8、of flights simulated, whereas no effect was noted on the basis of summation of cycle ratios 3. In tests using random-load sequences, the degree of load randomization present influences the fatigue life; life increases as the degree of the random ization increases. 4. The omission of the lowest load

    9、level did not significantly affect the number of flights simulated for tests in which the GAG cycle was introduced. 5. All the trends noted herein can be explained qualitatively by using the concepts of residual stresses and residual-static strength. Langley Research Center, National Aeronautics and

    10、 Space Administration, Langley Station, Hampton, Va., July 9, 1964. 20 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-APPENDIX CONVERSION OF U.S. CUSTOMARY UNITS TO SI UNITS The International System of Units (SI) was adopted by the Eleventh General

    11、Conference on Weights and Measures, Paris, October 1960, in Resolution No. 12 (ref. 4). Conversion factors required for units used herein are: Length: inches X 0.0254 = Meters (m) Force: pounds X 4.4482216 = Newtons (N) Time: minutes x 60 = Seconds (s) Frequency: cps = Hertz (Hz) Prefixes to indicat

    12、e multiples of units are: 106 mega (M) 10-3 milli (m) 21 I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REFERENCES 1. Naumann, Eugene C.; Hardrath, Herbert F.; and Guthrie, David E. : Axial-Load Fatigue Tests of 2024-T3and TOE-6 Aluminum-Alloy She

    13、et Specimens Under Constant- and Variable-Amplitude Loads. NASA TN D-212, 1959. 2. Naumann, Eugene C.; and Schott, Russell L.: Axial-Load Fatigue Tests Using Loading Schedules Based on Maneuver-Load Statistics. NASA TN D-1253, 1962. 3. Naumann, Eugene C.: Variable-Amplitude Fatigue Tests With Partic

    14、ular Attention to the Effects of High and Low Loads. NASA TN D-1522, 1962. 4. Anon.: International System of Units, Resolution No. 12. NASA TT F-200,1964. 5. Neuber, Heinz: Theory of Notch Stresses: Principles for Exact Stress Cal culation. J. W. Edwards (Ann Arbor, Mich.), 1946. 6. Grover, H. J.; B

    15、ishop, S. Mj and Jackson, L. R.: Fatigue Strengths of Air craft Materials. Axial-Load Fatigue Tests on Unnotched Sheet Specimens of 24S-T3and 75s-6 Aluminum Alloys and of SAE 4130 Steel. NACA TN 2324, 1951. 7. Grover, H. J.; Hyler, W. S.; Kuhn, Paul; Landers, Charles B.; and Howell, F. M.: Axial-Loa

    16、d Fatigue Properties of 24s-T and 75s-TAluminum Alloy as Determined in Several Laboratories. NACA Rep. 1190, 1954. (Supersedes NACA TN 2928.) 8. %ode, Richard V.; and Donely, Philip: Frequency of Occurrence of Atmos pheric Gusts and of Related Loads on Airplane Structures. NACA WR L-121,1944. (Forme

    17、rly NACA ARR LkI2l. ) 9. Taussky, Olga; and Todd, John: Generation and Testing of Pseudo-Random Numbers. Symposium on Monte Carlo Methods, John Wiley and Copp, Martin R.: Summary of VGH and V-G Data Obtained From Piston-Engine Transport Airplanes From 1947 to 1958. NASA TN G29, 1959. 11. Anon.: A Te

    18、ntative Guide for Fatigue Testing and the Statistical Analysis of Fatigue Data. Special Tech. Pub. No. 9l-A, ASTM, 1958. 12. McEvily, Arthur J., Jr.; Illg, Walter; and Hardrath, Herbert F. : Static Strength of Aluminum-Alloy Specimens Containing Fatigue Cracks. NACA TN 3816, 1956. 13. Hudson, C. Mic

    19、hael; and Hardrath, Herbert F.: Investigation of the Effects of Variable-Amplitude Loadings on Fatigue Crack Propagation Patterns. NASA Tm D-1803,1963. 22 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE I.- TENSIIX PROPERTIES OF ALUMINUM-ALLOY.

    20、MATERIALS TESTEB Eats from ref. 73 7075-T6 (152 tests) Property Average Minimum Yield stress (0.2-percent off set) -Inksi. . 75 *50 71 54 In W/m2 . 520.2 492.9 Ultimate tensile strength -Inksi 82.94 In m/m2 . 5719 5 Total elongation (2-inch (5.08-cm) gage length), percent 12.3 2024-T3 (147 tests) Yi

    21、eld stress (0.2-percent offset) -Inksi 46.88 In W/m2 . 323 0 Ultimate tensile strength -Inksi. . 72.14 70.27 In m/m2 . 497.0 484.2 Total elongation (2-inch(5.08-cm) gage length), percent 21.6 1 15.0 Maximum 79 - 79 549.8 84.34 582*5 15.0 59.28 408.4 73.44 506.0 25.0 Provided by IHSNot for ResaleNo r

    22、eproduction or networking permitted without license from IHS-,-,-TABLE 11.- VARIABLEAMPLITUDE LOAD PROGRAMS APPROXIMATING A GUST-LOAD HISTORY 7075-T6 aluminum-alloy specimens; Slg = 20 ksi (137.8 MN/m2) Load level Representative stress .-ksi m/m2 Relative frequency, cycles n/N per cycle 21.5 148.4 4

    23、2.000 0 25.3 174.6 28.7 198.0 32.6 224.9 7,5001,190 175 .00000625 .00006024 .00017241 36.3 250.5 23 .00034482 40.1 276 9 7 2.5 .00067120 43.9 302.9 *5 .00122000 47.5 327.8 .I .00208000 RGAG = 0; GAG cycle Sig to 0 (20 ksi to 0) (137.8 m/m2 to 0) . . . . . . . . . . . . . . . . . .00002000 RGAG = -1/

    24、2; GAG cycle SIg to -1/2Slg (20 ksi to -10ksi) (137.8 m/m2 to -68.9 MN/m2). . . . . . . . .00006293 2024-T3 aluminum-alloy specimens; Slg = 17.4 ksi (119.9 MN/m2) - 19.5 134.4 82, ooo 0 22.5 155 0 15, ooo .00000111 25.6 176.4 2,800 .00001370 28.7 197.7 350 .00005411 31.9 219.8 46 .00015391 35 -1 241

    25、.8 7.4 .00036216 38.4 264.6 1.6 .00075500 41.5 285 9 35 .00013314 %AG = -1/2; GAG cycle Sig to -1/2Slg (17.4 ksi to -8.7 ksi) (119.9 MN/m2 to -59.9 MN/m2) . . . . . . . .00002325 -.- . .- . . 24 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE 1

    26、11.- RESULTS OF CONSTANT-AMPLITUDE FATIGUE TESTS Specimen Geometric Life, cycles 53,00052, ooo 49,000 40,000 39,00030, ooo mean . . . 43,000 I (b) 7075-T6 aluminum alloy hean= 5 ksi (34.4 MN/m2); -. Specimen B93N2-6 B93N2-1 862-8 862-3 B103N2-7 Geometric mean %a = 20 ksi (137.8 MN/m2U Life, cycles 2

    27、0,570 15,650 15,530 15, 090 13,430 . . . 15,890 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-t TABLE IV.- RESULTS OF VARIABLE-AMPLITUDE FATIGUE TESTS ON 7075-T6 ALUMINUM-ALLOY SPECIMEN Elg = 20 ksi (137.8 MN/m2fl (a) Block tests to evaluate possib

    28、le machine difference at failure cycles Flights _.-Semiautomatic loading; step 1 omitted; reference 3 B11ON1- 1 142,120 2.54 11,843 B103N1- 9 125,690 2.36 10,474 BllON1- 2 121,450 2.20 10,121 1031-B1OlNl-2 99,170-2Ii.2z 1.85 1.71 8,2648,115 Geometric mean . . . . . . . . 115,700 2.09 9,641 -_ B103N1

    29、-3 114,450 1.98 9,5372 Automatic loading; same as reference 3 . -. . _ 1322-6 4 140,900 2.54 11,742 B126N2-4 2 123,035 2.21 10,2531042-5 7 115,759 2.10 9,647B124N2-5 7 115,759 2.10 9,6471372-6 6 115,560 2.06 9,630B13lN2-5 3 115,111 2.01 2x223 Geometric mean . 120,600 2.15 io, 058 26 Provided by IHSN

    30、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE IT.- RESULTS OF VARIABLE-AMPLITUDE FATIGUE TESTS ON 7075-T6 “UM-ALLOY SPECIMEN - Continued -(b) Random cycle tests to evaluate randomness of random sequence generation method* Specimen Flights Start at card 1 B9N

    31、2-3 122-3 92 6 82-5 B14N2-7 B9N2-9 Geometric mean . . Start at B129N2-5 5 BM-7 4 1322-10 51292-10 4 1282-1 5B9N2-7 5102-3 6 Geometric mean . . . . . . . . . . . . Start at Geometric mean . . . . . . . . . . . . Start at -B42-9 6 BlN2-1 4 82-9 4 B42-6 782-9 7su2-9 4 19,89019,55015,23213,49812,41012,3

    32、76 0.43 .42 .33 * 29 .27 3 1,5151,4891,162 1,031945 -2% 15,170 0.33 1,158 card 500 19,78819,31219,10815,47015,30013,97413,498 0.43 .42 .42 .34 .33 .30 2.2 1,4981,466 1,4511,1731,160 1,0571,023 16,450 0.36 1,256 card 1000 17,63114,926 1,3691,122 14,75614,75614,75614,722 1,1091,109 1,log1,108 15,225 1,162 card 1500 20,842 20,196 18,25814,21214,212 13,940 1,5921,5441,394 1, 087 1,0871,066 Geometric mean . . . . . . . . . . . . 16,670 1,272 * Highest load level occurs on card 1435. 27 I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-


    注意事项

    本文(NASA-TN-D-1584-1964 Evaluation of the influence of load randomization and of ground-air-ground cycles on fatigue life《荷载随机化和地空循环对疲劳寿命的影响评估》.pdf)为本站会员(sumcourage256)主动上传,麦多课文档分享仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文档分享(点击联系客服),我们立即给予删除!




    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
    备案/许可证编号:苏ICP备17064731号-1 

    收起
    展开