6926475992

Y.H. Kim. R.P. Wei, D.E. Gordon. S.M. Speaker, and S.D. Manning

General Dynamics. Fort Worth, TX, Rept. No. NADC-83126*60-VOL-1.237 pp (Mar 1983) AD-A136 414

Key Word*: Joint* (junction*). Fatigue life. Crack propege-tion. Corrosion fatigue

A corrosion fatigue methodology ha* been developed for predicting the crack initiation and crack propagation be-havfer of machanicaffy-fastened joint*. An experrmentaf test program wa* atso conducted using 7075 T7651 alu-minum alloy and bete-anneeled Ti-6A1-4V alloy to evaluate the affacts of environment, te*t frequency, R-retio, holding-time, and stres* levei on corrosion fatigue behavior. Basad on this investigation. it was concluded that the reaction between aqueou* enyironment* and the 7075-T7651 alu-minum alloy appears to be limited.

Transport and Road Research Lab., Crowthorne, UK. Rept. No. TRRL-SUPPLEMENTARY-748, 23 pp (1982)

PB84-142769

Key Words: Bars, Reinforced concrete. Fatigue life, Flexural vibration

Continuous and butt-weldad specimens of three types of high-yield reinforcing bars in concrete were fatigue tested in bertding. Frequency was 3 Hz and endurances were up to 100 x 1,000,000 cycles. The performance of the bers was higher than that of simllar bars tested axieily inair. A modi-fied form of a pr*viousły accepted relationship between the stres* ranga and the number of cycles to failure is described.

84-1801

Deyelopment of Fatigue and Crack Propagation Design and Anałysia Methodology in a Corrońve Enyśronment for T ypic*! MechanicaUy-Faateneó Joint*. Yohime 2. State-of-the-Art Asseaonent

Y.H. Kim. S.M. Speaker, R.P. Wei, and S.D. Manning General Dynamics. Fort Worth, TX, Rept. No. NADC-83126-60-VOL*2, 86 pp (Mar 1983)

AD-A136 415

Key Word*: Joint* (junctions), Fatigue life. Crack propege-tion, Corrosion fatigue

Navy corrosion fatigue design raąuirements for meta Hic airframes and generał design practices for satisfylng these raquiremenfs ara brief/y revievved. The phenomenon of and mechanisms responsible for corrosion fatigue crack łntiation ara reviewed. The mechanisms discussed include the stresa-concentrstion pit mechanism, the film rupture mechenism, and the preferentiel dissolution mechanism. Two fracture macha nic* modeli ara described and discussed for quantłta-tłvely predicting the number of cycles to corrosion fatigue crack initiation: strcse-inłtiation life model and strain-inłtie-tton life model.

841803

The Influence of Enyironment and Stres* Ratio on the Low Frequency Fatigue Crack Growth Behaviour of Two Medmm-Strength Quenched and Teropered Steela

B.F. Jones

Naval Aircraft Materials Lab., RN Aircraft Yard. Fleetlands, Gosport, Hants P013 OAW, UK, Intl. J. Fatigue. _6_(2), pp 75-81 (Apr 1984) 8 figs. 1 table, 22 refs

Key Words: Fatigue life, Crack propagation, Steel

The results of low fraęuency corrosion fatigue crack growth test* on HY130 and Q1N steels are reported and compered. Tha similaritie* and differences In tha responsa of the two steals to variatk>ns in anwironmant and stres* ratio are high-lighted and discussed In term* of some recent theorie* of corrosion fatigue crack growth and the impurKy element embrittlement of grain boundaries.

84-1802

Bendńtg Fatigue of High-Ysekl Reinforcmg Bara in Concrett

D.S. Moss 84-1804

Simple Fatigue Life Calculationa for Syncfcrooous ExciUtk>n Beaed on the Mohr'* Failure Limit (Ein-fache Schwingfeatigkeitarechnung fUr synchtone Bean^michung auf der Basia der Yeraagenyewe nach Mohr)

E. El-Magd