Crack growth data A and m

(1) A and m are obtained from crack growth measurements on standard notched specimens orientated in the LT, TL or ST direction (e.g. see Figure B.3.1) using standardised test methods (e.g. see Reference B.8.3). The specimen design must be one for which an accurate stress intensity factor (K) solution (i.e. the relationship between applied load and crack size 'af) is available. Recommended thickness w 20 < b< w 4 Recommended thickness w 20 < b< w 4 Fig.B.3.1. Typical crack growth...

References

B.8.1 AW guidance on assessment of the fitness for purpose of welded structures. IIW Draft for Development doc. SST-1157-90. B.8.2 Guidance on some methods for the derivation of acceptance levels for detects in fusion welded joints. British Standard Published Document 6493 1991. B.8.3 Standard test method for measurement of fatigue crac k growth rates, ASTM E647-93. B.8.4 Fatigue crack propagation in aluminium, IIW Document XIII-B77-90. B.8.5 Stress intensity factor equations for cracks in...

Fatigue Strength Data Classified details

1 P The generalised form of the Aa-N relationship is shown in figure 1.5.2, plotted on logarithmic scales. The design curve represents a mean minus 2 standard deviation level below the mean line through experimental data. 2 P The basic fatigue design relationship for endurances less than 5 x 106 cycles is defined by the equation Nj is the predicted number of cycles to failure of a stress range Acjj Aac is the reference value of fatigue strength at 2 x 106 cycles, depending on the category of...

Stress range parameters for specific Initiation Sites

4.4.1 Parent material, full penetration butt welds and mechanically fastened joints see Tables 5.1.5, 5.1.2, 5.1.3 and initiation sites 1,2,3,7 and 9 in Table 5.1.3 . 1 P Cracks initiating from weld toes, fastener holes, fraying surfaces, etc. and propagating through parent material or fully penetrated weld metal shall be assessed using the nominal principal stress range in the member at that point see Fig.4.2.1 . 2 P The local stress concentration effects of weld profile, bolt and rivet holes,...

Principles B Flaw dimensions

Planar Flaws Fatigue

1 Fatigue propagation is assumed to start from a pre-existing planar flaw with a sharp crack front orientated normal to the direction of principle tensile stress fluctuation Act at that point. 2 The dimensions of the pre-existing flaws are shown in Figure B.2.1 depending on whether they are surface breaking or fully embedded within the material. Figure B.2.1 Pre-existing planar flaws

Definitions

Rainflow Counting Method

1.5.1 Terms common to all Eurocodes 1 P Unless otherwise stated in Part 1 of Eurocode 9 the terminology used in International Standard ISO 8930 applies. 1.5.2 Special terms used in this Part 2 of Eurocode 9 1 P The following terms are used in Part 2 of Eurocode 9 w ith the following meanings - Fatigue Weakening of a structural part, through gradual crack propagation caused by repeated stress fluctuations. - Fatigue loading A set of typical load events described by the positions or movements of...

Hot spot stresses

1 The hot spot stress approach is used mainly for joints in which the weld toe orientation is transverse to the fluctuating stress component, and the crack is assumed to grow from the weld toe. The approach is not suitable for joints in which the crack would grow from embedded defects or from the root of a fillet weld. Compared with the nominal stress approach, this approach is more suitable for use in the following cases a there is no clearly defined nominal stress due to complicated...

Applicability of Nominal Modified Nominal and Hot Spot Stresses Nominal stresses

Elastic Stress

1 P Nominal stresses shall be used directly for the assessment of initiation sites in simple members and joints where the following conditions apply a The details associated with the site are in reasonable agreement with the appropriate detail category requirements in Tables 5.1.1 to 5.1.5. b The detail category has been established by test in accordance with Annex C and where the results have been expressed in terms of the nominal stresses. c Gross geometrical effects such as those listed in...

Full scale testing

1 Full scale testing may be carried out under actual operating conditions, or in a testing facility with the test load components applied by hydraulic or other methods of control. 2 The conditions for manufacturing the structure should be as for component testing in C.3.1. 3 The loads applied should not exceed the nominal loads. 4 Where the service loads vary in a random manner between limits they should be represented by an equivalent series of loads agreed between the supplier and the...

Partial Safety Factors for Fatigue Loading

1 Where the fatigue loading has been derived in accordance with the requirements of 3.2 a partial safety factor on load intensity yFf i gjmay be assumed to provide an acceptable level of safety. 2 Where a fatigue loading has been based on other confidence limits than those in 3.2 4 , an acceptable level of safety may be assumed to be provided by applying the partial safety factors on loading in Table 3.4.1. Table 3.4.1 Partial safety factors for fatigue load intensity yFf Table 3.4.1 Partial...

Control of welding quality

Welding Discontinuity Image

1 The manufacturer shall conform with the quality requirements of EN 729-2. D.1.2.2 Welding co-ordination 1 The welding co-ordination personnel shall have comprehensive technical knowledge in accordance with EN 719. 1 Welding procedures shall be approved in accordance with EN 288-4. D.1.2.4 Welder approval 1 Welders shall be approved in accordance with EN 287-2. D.1.2.5 Welding processes 1 Control of welding shall be in accordance with EN 1011-1 and 4. D.1.3 Methods and extent of Inspection 1...