Dimpling process in cold roll metal forming by finite element modelling and experimental validation

The dimpling process is a novel cold-roll forming process that involves dimpling of a rolled flat strip prior to the roll forming operation. This is a process undertaken to enhance the material properties and subsequent products’ structural performance while maintaining a minimum strip thickness. In order to understand the complex and interrelated nonlinear changes in contact, geometry and material properties that occur in the process, it is necessary to accurately simulate the process and validate through physical tests. In this paper, 3D non-linear finite element analysis was employed to simulate the dimpling process and mechanical testing of the subsequent dimpled sheets, in which the dimple geometry and material properties data were directly transferred from the dimpling process. Physical measurements, tensile and bending tests on dimpled sheet steel were conducted to evaluate the simulation results. Simulation of the dimpling process identified the amount of non-uniform plastic strain introduced and the manner in which this was distributed through the sheet. The plastic strain resulted in strain hardening which could correlate to the increase in the strength of the dimpled steel when compared to plain steel originating from the same coil material. A parametric study revealed that the amount of plastic strain depends upon on the process parameters such as friction and overlapping gap between the two forming rolls. The results derived from simulations of the tensile and bending tests were in good agreement with the experimental ones. The validation indicates that the finite element analysis was able to successfully simulate the dimpling process and mechanical properties of the subsequent dimpled steel products

Compressive Strength Tests and Design of Cold-formed Plain and Dimpled Steel Columns

This paper presents the experiments and design formulae of cold-formed plain and dimpled steel columns. A series of compression tests on plain and dimpled channel columns were conducted over a range of different geometries and the strength of the columns were investigated. The change in strength of the dimpled columns resulting from the cold working associated with the dimpling process was considered. The results showed that the buckling and ultimate strengths of dimpled steel columns were up to 33% and 26% greater than plain steel columns, respectively. The test results were evaluated by comparing buckling and ultimate loads of plain and dimpled channel columns with the values predicted by theoretical and semi-empirical methods. It was found that the predicted buckling and ultimate loads correlated well with the experimental results. Based on the experimental results, expressions for determining buckling and ultimate strengths of component plate elements of plain and dimpled channel columns were formulated

GPs' use of problem solving therapy for depression: a qualitative study of barriers to and enablers of evidence based care

BACKGROUND: Depression is a major health concern, predominantly treated by general practitioners (GPs). Problem solving therapy (PST) is recognised as an effective treatment for depression that is not widely used by GPs. This research aims to explore barriers and enablers that may influence GPs use of this treatment. METHOD: Qualitative methodology was used including individual and focus group interviews of GPs, PST experts and consumers. Analysis was undertaken using the Theory of Planned Behaviour (TPB) as a framework. RESULTS: A spectrum of potential influences, on GPs' use of PST emerged. Both barriers and enablers were identified. PST was perceived as being close to current practice approaches and potentially beneficial to both doctor and patient. In addition to a broadly positive attitude to PST, expressed by those with previous experience of its use, potential solutions to perceived barriers emerged. By contrast some GPs expressed fear that the use of PST would result in loss of doctor control of consultations and associated potential adverse patient outcomes. Patient expectations, which emerged as not always coinciding with GPs' perception of those expectations, were identified as a potential influence on GPs' decision concerning adoption of PST. In addition specific factors, including GP skill and confidence, consultation time constraints and technical issues related to PST were noted as potential concerns. CONCLUSION: This research contributes to our knowledge of the factors that may influence GPs' decisions regarding use of PST as a treatment for depression. It recognises both barriers and enablers. It suggests that for many GPs, PST is viewed in a positive light, providing encouragement to those seeking to increase the provision of PST by GPs. In identifying a number of potential barriers, along with associated options to address many of these barriers, it provides insights which may assist in the planning of GP training in PST

Explicit dynamics finite element analysis of energy absorption characteristics of thin-walled UltraSTEEL columns

UltraSTEEL material has been reported to have higher yield and ultimate strengths than plain mild steel under quasi-static loads. This project aims to study the energy absorption characteristics of UltraSTEEL thin-walled structures when subjected to axial impact loads. The numerical modelling starts from duplicating the UltraSTEEL dimpling process and defining the resultant material properties by taking strain hardening and strain rate sensitivity into consideration. Features including element type, mesh density, symmetric boundary conditions and imperfections are then studied. The responses of 1mm gauge plain and UltraSTEEL columns to the same impact load are compared by conducting explicit dynamics finite element simulations. Comparing to the plain columns, the effect of gauge on the UltraSTEEL columns’ failure mode and specific energy absorption (SEA) are analysed through a parametric study.Hadley Industries Holdings Limite

Process evaluation for complex interventions in primary care: understanding trials using the normalization process model

Background: the Normalization Process Model is a conceptual tool intended to assist in understanding the factors that affect implementation processes in clinical trials and other evaluations of complex interventions. It focuses on the ways that the implementation of complex interventions is shaped by problems of workability and integration.Method: in this paper the model is applied to two different complex trials: (i) the delivery of problem solving therapies for psychosocial distress, and (ii) the delivery of nurse-led clinics for heart failure treatment in primary care.Results: application of the model shows how process evaluations need to focus on more than the immediate contexts in which trial outcomes are generated. Problems relating to intervention workability and integration also need to be understood. The model may be used effectively to explain the implementation process in trials of complex interventions.Conclusion: the model invites evaluators to attend equally to considering how a complex intervention interacts with existing patterns of service organization, professional practice, and professional-patient interaction. The justification for this may be found in the abundance of reports of clinical effectiveness for interventions that have little hope of being implemented in real healthcare setting

The effectiveness of problem solving therapy in deprived South African communities: results from a pilot study

<p>Abstract</p> <p>Background</p> <p>The majority of South Africans with a DSM-IV diagnosis receive no treatment for their mental health problems. There is a move to simplify treatment for common mental disorders (CMDs) in order to ease access. Brief problem solving therapy (PST) might fill the treatment gap for CMD's in deprived communities in South Africa. This pilot study evaluates the feasibility, acceptability and effectiveness of this PST program for CMD's in deprived communities around Cape Town.</p> <p>Methods</p> <p>A Dutch problem solving program was adapted and translated into English, Xhosa and Afrikaans and thereafter implemented in townships around Cape Town. An initial attempt to recruit participants for online PST proved difficult, and so the program was adapted to a booklet format. Volunteers experiencing psychological distress were invited to participate in the either individually or group delivered 5-week during self-help program. To evaluate the effectiveness, psychological distress was administered through self-report questionnaires. After completion of the intervention participants also rated the program on various acceptability aspects.</p> <p>Results</p> <p>Of 103 participants, 73 completed 5 weeks of brief PST in a booklet/workshop format. There were significantly more dropouts in those who used the booklet individually than in the group. Psychological distress measured on the K-10 and SRQ fell significantly and the program was evaluated positively.</p> <p>Conclusions</p> <p>The results suggest that brief problem solving in a booklet/workshop format may be an effective, feasible and acceptable short-term treatment for people with CMD's in deprived communities. In this setting, group delivery of PST had lower drop-out rates than individual delivery, and was more feasible and acceptable. Randomized controlled trials are needed to evaluate the effect of brief self-help PST more rigorously.</p

Frequent attenders in general practice: problem solving treatment provided by nurses [ISRCTN51021015]

BACKGROUND: There is a need for assistance from primary care mental health workers in general practice in the Netherlands. General practitioners (GPs) experience an overload of frequent attenders suffering from psychological problems. Problem Solving Treatment (PST) is a brief psychological treatment tailored for use in a primary care setting. PST is provided by nurses, and earlier research has shown that it is a treatment at least as effective as usual care. However, research outcomes are not totally satisfying. This protocol describes a randomized clinical trial on the effectiveness of PST provided by nurses for patients in general practice. The results of this study, which currently being carried out, will be presented as soon as they are available. METHODS/DESIGN: This study protocol describes the design of a randomized controlled trial to investigate the effectiveness and cost-effectiveness of PST and usual care compared to usual care only. Patients, 18 years and older, who present psychological problems and are frequent attenders in general practice are recruited by the research assistant. The participants receive questionnaires at baseline, after the intervention, and again after 3 months and 9 months. Primary outcome is the reduction of symptoms, and other outcomes measured are improvement in problem solving skills, psychological and physical well being, daily functioning, social support, coping styles, problem evaluation and health care utilization. DISCUSSION: Our results may either confirm that PST in primary care is an effective way of dealing with emotional disorders and a promising addition to the primary care in the UK and USA, or may question this assumption. This trial will allow an evaluation of the effects of PST in practical circumstances and in a rather heterogeneous group of primary care patients. This study delivers scientific support for this use and therefore indications for optimal treatment and referral

Cost-effectiveness of problem-solving treatment in comparison with usual care for primary care patients with menthal health problems: a randomized trial

BACKGROUND: Mental health problems are common and are associated with increased disability and health care costs. Problem-Solving Treatment (PST) delivered to these patients by nurses in primary care might be efficient. The aim of this study was to evaluate the cost-effectiveness of PST by mental health nurses compared with usual care (UC) by the general practitioner for primary care patients with mental health problems. METHODS: An economic evaluation from a societal perspective was performed alongside a randomized clinical trial. Patients with a positive General Health Questionnaire score (score ≥ 4) and who visited their general practitioner at least three times during the past 6 months were eligible. Outcome measures were improvement on the Hospital Anxiety and Depression Scale and QALYs based on the EQ-5D. Resource use was measured using a validated questionnaire. Missing cost and effect data were imputed using multiple imputation techniques. Bootstrapping was used to analyze costs and cost-effectiveness of PST compared with UC. RESULTS: There were no statistically significant differences in clinical outcomes at 9 months. Mean total costs were €4795 in the PST group and €6857 in the UC group. Costs were not statistically significantly different between the two groups (95% CI -4698;359). The cost-effectiveness analysis showed that PST was cost-effective in comparison with UC. Sensitivity analyses confirmed these findings. CONCLUSIONS: PST delivered by nurses seems cost-effective in comparison with UC. However, these results should be interpreted with caution, since the difference in total costs was mainly caused by 3 outliers with extremely high indirect costs in the UC group. TRIAL REGISTRATION: Nederlands Trial Register ISRCTN5102101

A pilot randomized controlled trial of a stepped care intervention package for depression in primary care in Nigeria

Background Depression is common in primary care and is often unrecognized and untreated. Studies are needed to demonstrate the feasibility of implementing evidence-based depression care provided by primary health care workers (PHCWs) in sub-Saharan Africa. We carried out a pilot two-parallel arm cluster randomized controlled trial of a package of care for depression in primary care. Methods Six primary health care centers (PHCC) in two Local Government Areas of Oyo State, South West Nigeria were randomized into 3 intervention and 3 control clinics. Three PHCWs were selected for training from each of the participating clinics. The PHCWs from the intervention clinics were trained to deliver a manualized multicomponent stepped care intervention package for depression consisting of psychoeducation, activity scheduling, problem solving treatment and medication for severe depression. Providers from the control clinics delivered care as usual, enhanced by a refresher training on depression diagnosis and management. Outcome measures Patient’s Health Questionnaire (PHQ-9), WHO quality of Life instrument (WHOQOL-Bref) and the WHO disability assessment schedule (WHODAS) were administered in the participants’ home at baseline, 3 and 6 months. Results About 98% of the consecutive attendees to the clinics agreed to have the screening interview. Of those screened, 284 (22.7%) were positive (PHQ-9 score ≥ 8) and 234 gave consent for inclusion in the study: 165 from intervention and 69 from control clinics. The rates of eligible and consenting participants were similar in the control and intervention arms. In all 85.9% (92.8% in intervention and 83% in control) of the participants were successfully administered outcome assessments at 6 months. The PHCWs had little difficulty in delivering the intervention package. At 6 months follow up, depression symptoms had improved in 73.0% from the intervention arm compared to 51.6% control. Compared to the mean scores at baseline, there was improvement in the mean scores on all outcome measures in both arms at six months. Conclusion The results provide support for the feasibility of conducting a fully-powered randomized study in this setting and suggest that the instruments used may have the potential to detect differences between the arms