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Application and recent research on direct analysis with completed projects in Macau and Hong Kong
Published in Kok Keong Choong, Mustafasanie M. Yussof, Jat Yuen Richard Liew, Recent Advances in Analysis, Design and Construction of Shell and Spatial Structures in the Asia-Pacific Region, 2019
Siu-Lai Chan, Y. P. Liu, S. W. Liu
Member imperfection may increase the bowing effect and induce the P-δ moment, which is important when the member is subjected to a large compression. Member imperfections include initial geometric imperfections and residual stresses. The initial geometric imperfections may be due to one or several aspects such as cambering, sweeping, twist, out of straightness, and cross-section distortion. The residual stresses can be due to manufacturing and fabrication processes. In de Normalización (2005) and CoPHK (2011), the two kinds of imperfections are simply combined into an equivalent geometric imperfection, while AISC (2016) adopts 0.1% member length as geometric imperfection and explicitly considers residual stress by a modified modulus approach. In this chapter, the equivalent initial bowing imperfections following CoPHK (2011) is adopted for the tapered I-beams. The beam-column element described in the previous section is used to model the tapered I-beams.
Welds, Their Quality and Inspection Ability for High Integrity Structures and Components
Published in Peter Hirsch, David Lidbury, Fracture, Plastic Flow and Structural Integrity, 2019
R.E. Dolby, I.J. Munns, C.R.A. Schneider, R.H. Leggatt
The use of these analytical and experimental techniques has led to a greater knowledge and understanding of the effect of component geometry, restraint, welding procedure, thermal properties, mechanical properties, phase changes and transformation plasticity on the magnitudes and distributions of residual stresses in welded joints.20 This knowledge has led to more accurate analysis of the role of residual stresses in failure mechanisms, to the development of techniques for reducing residual stresses in sensitive locations, and to the preparation of standardised residual stress profiles for use in assessing the acceptability of defects in welded structures.21–23
Additive Manufacturing of Metals Using Powder Bed-Based Technologies
Published in Amit Bandyopadhyay, Susmita Bose, Additive Manufacturing, 2019
M. J. Mirzaali, F. S. L. Bobbert, Y. Li, A. A. Zadpoor
Residual stress is the stress present in a body when no external forces are applied and the other mechanical and thermal loads are in equilibrium (Figure 4.4a). Residual stresses are the results of local and global thermal gradients and the high cooling/heating rates experienced during and after the printing process [207]. Therefore, the magnitude of the residual stresses is dependent on the thermal history experienced during the AM processes. The presence of residual stresses has a significant effect on the mechanical performance (e.g., tensile strength and fatigue resistance) and lack of geometric accuracy in AM parts [208].
A review on severe plastic deformation based post-processes for metal additive manufactured complex features
Published in Materials and Manufacturing Processes, 2023
S.M. Basha, N. Venkaiah, T.S. Srivatsan, M.R. Sankar
Shot peening is a process of improving the fatigue life of components by producing compressive residual stresses.[72] In this process, highly energetic tiny metallic or ceramic balls, known as shots, are bombarded on the target surface to create an array of dimples by plastic deformation or cold working.[73] The strain associated with the deformation increases the surface hardness,[74] fatigue life[75,76] and imparts residual stresses on the surface.[77] This process is extensively used in industries specific to aviation and automobile to relieve the tensile residual stresses generated during grinding and other machining processes.[78,79] A schematic of the surface improvement resulting from the shot peening process is shown in Fig. 6(b). Even though this process is not a surface finishing process, few researchers[83–85] have used this process to improve the surface morphology of the target surface. As the additively manufactured (AM) components have a high surface roughness, this process improves the surface roughness by significantly deforming the surface peaks, resulting in isotropic surfaces.[86]
Investigation on Residual Stress in SA508/Inconel Metal/CF8A Dissimilar Welded Joint for Nuclear Steam Generator Safe End Using Different Processes
Published in Nuclear Technology, 2023
Zhifang Gao, Lei Zhao, Yongdian Han
In a nuclear reactor, DMW is usually composed of more than two materials with different mechanical, thermal, and fracture properties due to different natures, chemical compositions, and mixtures of filler and base metals, which produces high inhomogeneity across the DMW and leads to degradation of ferritic steel, metallurgical deterioration at interfaces, and residual stress during cladding and butt welding processes. Among these factors, residual stress, especially tensile residual stress, is a critical factor and greatly affects the reliability of components with DMWs.[9–13] In the case of DMWs, the mismatch in thermal expansion coefficient between austenitic and ferritic steel causes a complex residual stress profile. Moreover, residual stress can result in stress corrosion cracking (SCC) by creating tensile stress, introducing a susceptible material when exposed to a corrosive environment. The performance and integrity of welded structures considerably deteriorate due to residual stress at the welding zone.
Electromagnetic (EM) sensor measurement for residual stress characterisation in welded steel plates
Published in Nondestructive Testing and Evaluation, 2023
Edosa Osarogiagbon, Russ Hall, Lei Zhou, Janka Cafolla, Claire Davis
Residual stresses are stresses in materials or finished components in the absence of applied stress. Welded components are particularly prone to the effects of residual stresses, welding is a high-energy process which causes residual stresses around the weld which can affect a component’s strength, toughness and fatigue life. The presence of residual stresses can cause unexpected failures; measurement of residual stresses allows their effects to be managed [1]. Various methods of measuring residual stress have been developed [1,2], including destructive and non-destructive methods [3–6]. Destructive methods include the contour method [7–10], slitting method [11–14], blind hole drilling (BHD) method [15–17], deep hole contour (DHC) method [18–20] and deep hole drilling method [21–25]. Non-destructive techniques include X-ray diffraction [19–21], neutron diffraction [26, 27], electromagnetic (EM) [28–30] and ultrasonic methods [31–36].