Approach for testing the material behavior in roll forming in a small scale

Roll forming of ultra-high strength steels (UHSS) and other high strength alloys is an advanced manufacturing methodology with the ability of cold forming those materials to complex three-dimensional shapes for lightweight structural applications. Due to their high strength, most of these materials have a reduced ductility which excludes conventional sheet forming methods under cold forming conditions. Roll forming is possible due to its low strains and incremental forming characteristic. Recent research investigates the development of high strength nano-structured aluminum sheet and titanium alloys, as well as their behaviour in roll forming with regard to formability, material behaviour and shape defects. The development of new materials is often limited to small scale samples due to the high preparation costs. In contrast, industrial application needs larger scale tests for validation, especially in roll forming where a minimum sheet length is required to feed the sample trough the roll forming machine. This work describes a novel technique for studying roll forming of a short length of experimental material. DP780 steel strips (500mm &ndash; 1300mm length) were welded between two mild steel carrier sheets of similar width and thickness giving an overall strip length of 2m. Roll forming trials were performed and longitudinal edge strain, bow and springback determined on the welded samples and samples formed of full length DP780 strip before and after cut off. The experimental results of this work show that this method gives a reasonable approach for predicting material behavior in roll forming transverse to the rolling direction. In contrast to that significant differences in longitudinal bow were observed between the welded sections and the sections formed of full length DP780 strip; this indicates that the applicability of this method is limited with regard to predicting longitudinal material behavior in roll forming.<br /

Numerical analysis of the flexible roll forming of an automotive component from high strength steel

Conventional roll forming is limited to components with uniform cross-section; the recently developed flexible roll forming (FRF) process can be used to form components which vary in both width and depth. It has been suggested that this process can be used to manufacture automotive components from Ultra High Strength Steel (UHSS) which has limited tensile elongation. In the flexible roll forming process, the pre-cut blank is fed through a set of rolls; some rolls are computer-numerically controlled (CNC) to follow the 3D contours of the part and hence parts with a variable cross-section can be produced. This paper introduces a new flexible roll forming technique which can be used to form a complex shape with the minimum tooling requirements. In this method, the pre-cut blank is held between two dies and the whole system moves back and forth past CNC forming rolls. The forming roll changes its angle and position in each pass to incrementally form the part. In this work, the process is simulated using the commercial software package Copra FEA. The distribution of total strain and final part quality are investigated as well as related shape defects observed in the process. Different tooling concepts are used to improve the strain distribution and hence the part quality

Integrating mental health into primary care for post-conflict populations: a pilot study

Background Mental health care in post-conflict settings is often not prioritized, despite its important public health role. There is a salient gap in integrating mental health into primary care, especially in post-conflict settings. In the post-conflict Northern province of Sri Lanka, a pilot study was conducted to explore the feasibility of integrating mental health into primary care through a mhGAP-based training intervention. Methods Using the mhGAP training intervention modules, a 24 h training programme was held over 3 days for primary care practitioners serving post-conflict populations (including internally displaced people and returnees). mhGAP intervention guide and video material was used in the training. Pre/post knowledge increase was measured. A qualitative study was also nested within the training programme to explore views, attitudes and perceptions of primary care practitioners on integrating mental health into primary care in the region. In-depth interviews were conducted. Results Twelve primary care practitioners participated. The average service duration of the group was 7.6 years. The mean pre- and post-test scores of the PCP group were 72.8 and 77.2 % respectively. All 12 took part in the qualitative component. Participants highlighted their experiences of conflict and displacement, discussed the health profiles/needs of post-conflict populations in the region and provided insight into mental health care and training needs at primary care level. Participants also provided feedback on the mhGAP-based training; the cultural and contextual relevance of training material and content. Conclusion This study was planned as a local demonstrative project to explore the feasibility of training primary care practitioners to promote the integration of mental health into primary care for post-conflict populations. To our knowledge, this is the first such attempt in Sri Lanka. Findings highlight the practical, operational and attitudinal barriers to integrate mental health into primary care, especially in resource-poor, post-conflict settings. Important feedback on mhGAP intervention guide, its implementation and training material was gained

Flexible roll forming of automotive components from ultra high strength steel

Conventional roll forming is limited to components with uniform cross-section; the recently developed flexible roll forming (FRF) process can be used to form components which vary in both width and depth. It has been suggested that this process can be used to manufacture automotive components from Ultra High Strength Steel (UHSS) which has limited tensile elongation and is unsuitable for stamping. In the flexible roll forming process, the pre-cut blank is fed through a set of rolls; some rolls are computer-numerically controlled (CNC) to follow the 3D contours of the part and hence parts with a variable cross-section can be produced. As with conventional roll forming, the number of forming stations is kept to a minimum, particularly the controlled roll stations, in order to limit tooling costs.This paper introduces a new flexible roll forming technique which can be used to form a complex shape with the minimum tooling requirements. In this method, the pre-cut blank is held between two dies and the whole system moves back and forth past CNC forming rolls. The forming roll changes its angle and position in each pass to incrementally form the part. In this work, the process is simulated using the commercial software package Copra FEA. The distribution of total strain and final part quality are investigated as well as related shape defects observed in the process. Different tooling concepts are used to improve the strain distribution and hence the part quality. The current work presents a new cost-effective flexible roll forming technique and minimizes the number of tool changes