Innovative Stainless Steel Applications in transport ... - Euro Inox

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5.2 Sandwich panel mechanical properties The mechanical testing programme carried out in the DOLTRAC project included both static bending tests for full-size 1250 mm × 2200 mm panels and fatigue testing of smaller panel sections, also in bending configuration. Further testing for sections was carried out in the crash test programme, described more in detail in Chapter 5.3. The panel details are collected in Table 33. Table 33. The details of the panels manufactured and tested in the experimental programme (DOLTRAC). The top sheet (i.e. the load-side sheet) was similar to all the other panels: 1.9 mm thick 1.4318 in C1000 condition. dim. = RHS tube dimensions or the angle of V(f) core, dist. = distance between individual core elements and t = sheet thickness. Panel type Core Bottom sheet dim. dist. mat. cond. tc mat. cond. t2 (mm) (mm) (mm) O-1 20 × 50 84 1.4318 C850 1.0 1.4318 C1000 1.2 O-2 20 × 50 84 304sp 2B 1.0 1.4318 C1000 1.2 O-3 20 × 50 84 1.4318 C850 1.0 1.4318 C850 1.5 O-4 20 × 50 84 304sp 2B 1.0 1.4318 C850 1.5 Vf-1 60 ° 74 1.4318 C850 1.0 1.4318 C1000 1.2 Vf-2 60 ° 74 304sp 2B 1.0 1.4318 C1000 1.2 Vf-3 60 ° 74 1.4318 C850 1.0 1.4318 C850 1.5 Vf-4 60 ° 74 304sp 2B 1.0 1.4318 C850 1.5 V-1 60 ° - 304sp 2B 1.0 1.4318 C1000 1.2 The panels were designed to minimise their weight for the predetermined design-load conditions: a 480 kg/m 2 = 4709 N/m 2 constant load combined with a 1.5 kN point load. The maximum allowable panel displacement was set at L/300 (6.67 mm for the selected span length of 2000 mm). Apart from the verification of full-size 1250 mm × 2200 mm panel properties against the design load, the ultimate strength was measured in fourpoint bending. Smaller, approximately 500 mm × 1000 mm panel samples were tested in three-point bending configuration under both static and fatigue loading and 200 - 400 mm × 1800 mm sections in quasi-static and crash tests. The fatigue programme was carried out with the worst case – maximum force amplitudes for the maximum load cycles (which would not occur in reality) – to see if the test specimens could bear these loads. The selected case was based on a typical equipment box of ~ 2.5 tons, mounted with eight brackets, inducing a force of 3000 N per bracket (i.e. a 3 kN point load) on a 100 × 100 mm 2 square representing the underfloor equipment-box bracket. This static load was superposed by ± 20 % dynamic loads, leading to R = 0.66 with an upper amplitude of 3600 N and a lower amplitude of 96
2400 N. Thus, the specified fatigue load was 3000 N ± 600 N applied to an area of 100 × 100 mm 2 for 10 7 cycles at a maximum frequency of 100 Hz. 5.2.1 Four-point bend testing of full-size panels The bending tests were carried out in a customisable load frame, using two separate loading cylinders and displacement control. The forces were measured directly from the hydraulic cylinders and the displacements from both the top and bottom panel surfaces. The bending tests were carried out using displacement control at a speed of ~ 3 mm/min. Details of the test arrangements can be found in Figure 59. Figure 59. Details of panels in the four-point bending test, showing a) top-sheet wrinkling under compressive load and b) failure caused by local buckling of the core element. Altogether, 18 full-size panels were tested by four-point bending. Apart from the maximum loading force and the corresponding displacements, an effort was also made to evaluate the yielding behaviour of the panels. Determining a reliable and common yield criterion for all the panels proved too difficult, however, mainly because the scatter originating from the distortion of the panels after welding was too great. Instead, the slope of the elastic region of each force-displacement curve was defined, to gain at least a rough estimate of the elastic behaviour of various panel types under loading. An effort was made to evaluate the elastic behaviour of the panels, by determining the slope of the load-displacement curve of each panel at the elastic region. Both panel types show – within reasonable scatter – approximately the same slope, which depends mainly on the thickness of the bottom sheet. Increasing the thickness from 1.2 mm to 1.5 mm results in a 15 - 20 % higher slope value. It is also noteworthy that the scatter is less for the thicker, bottom-sheet panels. In the theoretical panel-optimisation calculations, the decrease in displacement caused by the change of bottom-sheet thickness from 1.0 mm to 1.5 mm is 17.5 % and 18.4 % respectively for the O- and Vfpanels (i.e. comparable to the experimental results). 97
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Preface This publication is the mai
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Contents Preface ..................
Page 5:
List of symbols Mechanical properti
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Figure 1. Rear view of El Capitan.
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In Japan and the Asia-Pacific areas
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12 Figure 13. Delhi metro coach (Go
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1.3 Bus and coach applications 14 A
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1.4 Future potential Future prospec
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2. Materials By definition, stainle
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use higher nitrogen contents in aus
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Grade 1.4318 stainless steel was su
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MPa). Table 7 shows the format and
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1. Design using minimum specified v
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Table 9. The most common stainless
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Table 10. Physical properties of so
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for example, in the case of lap joi
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to develop new de-icing chemicals,
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(a) (b) Figure 30. Photograph from
Page 39 and 40:
Austenitic CrNi and CrNiMo stainles
Page 41 and 42:
Figure 33 shows the behaviour of fe
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(a) (b) Figure 35. Localised corros
Page 45 and 46: visual and not detrimental to struc
Page 47 and 48: Reduction factor 1 0.9 0.8 0.7 0.6
Page 49 and 50: It is typical of cold-worked stainl
Page 51 and 52: Thermomechanical treatments can be
Page 53 and 54: Table 17. The minimum values for co
Page 55 and 56: 3. Lightweight structures and desig
Page 57 and 58: K joints The requirements for K joi
Page 59 and 60: Figure 42. Overlapping joint (Yrjö
Page 61 and 62: Another typical way to join a hollo
Page 63 and 64: There are some disadvantages with a
Page 65 and 66: New challenges have to be met in bo
Page 67 and 68: Stiffness parameters Despite the li
Page 69 and 70: Figure 52. An experimental, sandwic
Page 71: 71 Figure 53. Stainless steel sandw
Page 74 and 75: values are shown in Table 20. A com
Page 76 and 77: Springback was determined by measur
Page 78 and 79: A “three-roll” (pyramid-type) b
Page 80 and 81: angle of 180 °. Figure 58 shows th
Page 82 and 83: design and the manufacture of the t
Page 84 and 85: Combined with modern pulsing techni
Page 86 and 87: possibility of transferring the bea
Page 89 and 90: 5. Properties of lightweight struct
Page 91 and 92: Table 28. Fusion welding results fo
Page 93 and 94: welding mechanical treatments. Howe
Page 95: performance of a weld-joint detail
Page 99 and 100: limited number of static bending te
Page 101 and 102: material strengths or manufacturing
Page 103 and 104: section at a velocity of 3.0 m/s. F
Page 105 and 106: (a) (b) (c) Figure 65. (a) Deflecti
Page 107 and 108: Figure 67. Panel sections after lon
Page 109 and 110: 6. Life cycle issues The transporti
Page 111 and 112: and services, occurring throughout
Page 113 and 114: 100 % 80 % 60 % 40 % 20 % 0 % Mater
Page 115 and 116: (especially in the case of lower-al
Page 117 and 118: Acknowledgements The following orga
Page 119 and 120: References Ala-Outinen, T. 1996. Fi
Page 121 and 122: DIN 6935. 1975. Kaltbiegen von Flac
Page 123 and 124: Federation of metals industries. ME
Page 125: UNEP 2002. Industry as a partner fo
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