Miguel Morales, Carlos Correa, Juan Antonio Porro, Carlos Molpeceres and José Luis Ocaña
Laser shock peening (LSP) is mainly a mechanical process, but in some cases, it is performed without a protective coating and thermal effects are present near the surface. The…
Abstract
Purpose
Laser shock peening (LSP) is mainly a mechanical process, but in some cases, it is performed without a protective coating and thermal effects are present near the surface. The numerical study of thermo‐mechanical effects and process parameter influence in realistic conditions can be used to better understand the process.
Design/methodology/approach
A physically comprehensive numerical model (SHOCKLAS) has been developed to systematically study LSP processes with or without coatings starting from laser‐plasma interaction and coupled thermo‐mechanical target behavior. Several typical results of the developed SHOCKLAS numerical system are presented. In particular, the application of the model to the realistic simulation (full 3D dependence, non‐linear material behavior, thermal and mechanical effects, treatment over extended surfaces) of LSP treatments in the experimental conditions of the irradiation facility used by the authors is presented.
Findings
Target clamping has some influence on the results and needs to be properly simulated. An increase in laser spot radius and an increase in pressure produces an increase of the maximum compressive residual stress and also the depth of the compressive residual stress region. By increasing the pulse overlapping density, no major improvements are obtained if the pressure is high enough. The relative influence of thermal/mechanical effects shows that each effect has a different temporal scale and thermal effects are limited to a small region near the surface and compressive residual stresses very close to the surface level can be induced even without any protective coating through the application of adjacent pulses.
Originality/value
The paper presents numerical thermo‐mechanical study for LSP treatments without coating and a study of the influence of several process parameters on residual stress distribution with consideration of pulse overlapping.
Details
Keywords
José L. Ocaña, Carlos Correa, Juan A Porro, Marcos Díaz, Leonardo Ruiz de Lara and David Peral
With the aid of the calculational system developed by the authors, the analysis of the problem of laser shock processing (LSP) treatment for induction of residual stress (RS…
Abstract
Purpose
With the aid of the calculational system developed by the authors, the analysis of the problem of laser shock processing (LSP) treatment for induction of residual stress (RS) fields for fatigue life enhancement in relatively thin sheets in a way compatible with reduced overall workpiece deformation due to spring-back self-equilibration has been envisaged. Numerical results directly tested against experimental results have been obtained confirming the critical influence of the laser energy and irradiation geometry parameters. The paper aims to discuss these issues.
Design/methodology/approach
Plane rectangular specimens (160 mm×100 mm×2 mm) of Al-cladded (∼80 μm) Al2024-T351 were considered both for LSP experimental treatment and for corresponding numerical simulation. The test piece is fixed on a holder and is driven along X and Y directions by means of an anthropomorphic robot. The predefined pulse overlapping strategy is used for the irradiation of extended areas of material. From the geometrical point of view, a full 3D configuration for the real geometry and for the sequential overlapping strategy of pulses has been considered. The FEM elements used for the simulation are an eight-node brick reduced integration with hourglass control in the treated area, namely C3D8RT, and a six-node trainer prism in the rest of the geometry, where there is no applied load, namely C3D6T, that ease meshing complex partitions. The element size in the nearest of the treated surface is 100×100×25 µm, being the maximum element size which allows to maintain calculation convergence.
Findings
Numerical results directly tested against experimental results have been obtained confirming: first, the critical influence of the laser energy and irradiation geometry parameters on the possible thin sheets deformation, both at local and global scales. Second, the possibility of finding LSP treatment parameter regimes that, maintaining the requirements relative to in-depth RSs fields, are able to reduce the relative importance of sheet deformation. Third, the possibility of finding LSP treatment parameter regimes able to provide through-thickness compressive RSs fields at levels compatible with an effective fatigue life enhancement. Fourth, the possibility of improving this through-thickness compressive RSs fields by double-side treatments. Fifth, the capability of the experimental LSP treatment system at the authors site (CLUPM) of practically achieve the referred through-thickness compressive RSs fields in excellent agreement with the predictive assessment obtained by the used numerical code (SHOCKLAS®).
Practical implications
The referred results provide a firm basis for the design of LSP treatments able to confer a broad range of RSs fields to thin components aiming the extension of their fatigue life, an enormously relevant field in which the authors are currently working.
Originality/value
The LSP treatment of relatively thin specimens brings, as an additional consequence, the possible bending in a process of laser shock forming. This effect poses a new class of problems regarding the attainment of specified RS’s depth profiles in the mentioned type of sheets, and, what can be more critical, an overall deformation of the treated component. The analysis of the problem of LSP treatment for induction of tentatively through-thickness RS’s fields for fatigue life enhancement in relatively thin sheets in a way compatible with reduced overall workpiece deformation due to spring-back self-equilibration is envisaged in this paper for the first time to the authors knowledge. The coupled theoretical-experimental predictive approach developed by the authors has been applied to the specification of LSP treatments for achievement of RS’s fields tentatively able to retard crack propagation on normalized specimens.
Details
Keywords
Pedro Dourado, Carmen LLovet and Eglée Ortega Fernández
Given the potential for authorial fashion to lead the way in the field of sustainable fashion and digital platforms to be a powerful tool for spreading sustainable messages, this…
Abstract
Purpose
Given the potential for authorial fashion to lead the way in the field of sustainable fashion and digital platforms to be a powerful tool for spreading sustainable messages, this study seeks to explore the emphasis given to sustainability in the digital communication of Portuguese and Spanish’s authorial fashion.
Design/methodology/approach
A thematic analysis of all the posts published on the feeds of the 63 designers who presented their collections at the Madrid and Lisbon fashion weeks in September/October 2022 (Spring/Summer 2023) or February/March 2023 (Fall/Winter 2023/2024) editions was carried out. The information was collected over a six-month period between the two fashion weeks. This study is based on the categories identified in the reflexive thematic analysis developed by Testa et al. (2020). After adapting the categories to our analysis, 14 emerging themes were identified as observation criteria.
Findings
A total of 4,699 posts were examined. The analysis reveals a general lack of interest in mentioning sustainability – a subject evident in just around 6% of the content – as well as a high emphasis on the visual aspect of the fashion product. Several similarities between the Portuguese and Spanish markets were observed.
Originality/value
This study is important since there are few cross-cultural studies in the field of fashion between the two countries, particularly on sustainable fashion. Furthermore, it establishes a structure that is easily replicable in various markets and geographical areas.
Details
Keywords
Bárbara Castillo-Abdul, Ana Pérez-Escoda and Sabina Civila
This paper aims to increase the understanding of luxury brands’ branded content strategies concerning follower's engagement generated or not by happiness and well-being feelings…
Abstract
Purpose
This paper aims to increase the understanding of luxury brands’ branded content strategies concerning follower's engagement generated or not by happiness and well-being feelings spread in their branded content.
Design/methodology/approach
This study sample was composed of three of the most relevant luxury brands nowadays: Manolo Blahnik, Loewe, y Balenciaga. To address this research, an exploratory-correlational quantitative methodology was chosen; hypotheses were contrasted using ANOVA analysis with the SPSS software. Although the study can be considered quantitative, the first step of qualitative analysis was applied for content analysis with NVivo QSR software, categorizing all posts (N = 192) into three categories.
Findings
The dissemination of branded content and corporate social responsibility, despite being different in each case, show in general an interaction and affective commitment with their stakeholders. In the specific case of Manolo Blahnik and Loewe, they have prioritized their content, in the context of the pandemic, in posts related to social welfare, happiness, mental and physical health care. There are significant differences in the interaction with their audience, which respond very favorably to both “Happiness” and “Health and safety” content.
Originality/value
This study reveals how corporate social responsibility can be achieved using efficient communications in social networks. In this way, the perception of the image of the sector and the reputation can be improved – both sectoral and organizational – which unquestionably translates into economic gains for the brands.
Details
Keywords
Bárbara Castillo-Abdul, Eglée Ortega Fernandez and Luis M. Romero-Rodriguez
This study aims to analyze the content on corporate social responsibility (CSR) of Gucci, Prada and Ermenegildo Zegna on the social networks Instagram, Facebook and TikTok in…
Abstract
Purpose
This study aims to analyze the content on corporate social responsibility (CSR) of Gucci, Prada and Ermenegildo Zegna on the social networks Instagram, Facebook and TikTok in order to examine the focus of the publications of these luxury brands, what type of content is more frequent and which ones generate more interaction and engagement.
Design/methodology/approach
An interpretive content analysis of a sample of 92 posts on CSR published between December 2021 and June 2022 is used. For this purpose, an analysis sheet validated through theoretical constructs and pilot testing is used.
Findings
Most of the social responsibility content of the fashion brands analyzed is linked to the use of sustainable materials, the protection of natural spaces and, in the particular case of Prada, the protection of the oceans. The posts that achieve the highest interactions are videos and photo reels. Although the strategies that significantly increase brands' reach on social networks are collaborations and joint posts with other fashion brands, as is the case of Gucci with NorthFace and Prada with Adidas. Also, one of the main findings of this research has been to identify that brands may be using TikTok – perhaps experimentally – to reach stakeholders in Asian countries, especially China, where other platforms such as Instagram or Facebook may have a more limited reach.
Originality/value
This research shows that the social responsibility activities of luxury fashion brands leverage the content marketing strategy in social networks. It also demonstrates the importance of the Asian market (mainly Chinese) in the outreach strategies of brands, as is the case of Gucci and Prada, which bet on CSR activities for the protection of the Asian tiger in the framework of the year of the tiger in the Chinese horoscope, as well as the publication of certain content on TikTok.