Review of approximate analyses of sheet forming processes

Approximate models are often used for the following purposes: in on-line control systems of metal forming processes where calculation speed is critical; to obtain quick, quantitative information on the magnitude of the main variables in the early stages of process design; to illustrate the role of the major variables in the process; as an initial check on numerical modelling; and as a basis for quick calculations on processes in teaching and training packages. The models often share many similarities; for example, an arbitrary geometric assumption of deformation giving a simplified strain distribution, simple material property descriptions - such as an elastic, perfectly plastic law - and mathematical short cuts such as a linear approximation of a polynomial expression. In many cases, the output differs significantly from experiment and performance or efficiency factors are developed by experience to tune the models. In recent years, analytical models have been widely used at Deakin University in the design of experiments and equipment and as a pre-cursor to more detailed numerical analyses. Examples that are reviewed in this paper include deformation of sandwich material having a weak, elastic core, load prediction in deep drawing, bending of strip (particularly of ageing steel where kinking may occur), process analysis of low-pressure hydroforming of tubing, analysis of the rejection rates in stamping, and the determination of constitutive models by an inverse method applied to bending tests.

Qualitative estimation of camera motion parameters from video sequences

We propose a simple technique for extracting camera motion parameters from a sequence of images. The method can estimate qualitatively camera pan, tilt, zoom, roll, and horizontal and vertical tracking. Unlike most other comparable techniques, the present method can distinguish pan from horizontal tracking, and tilt from vertical tracking. The technique can be applied to the automated indexing of video and film sequences.

Development of asymmetric rolling for the better control over structure and mechanical properties in IF steel

In the present study, the effects of kinematic and geometric asymmetries in rolling during multi-pass processing of IF steel are examined. The theoretical investigation by final element simulations and experimental investigations by means of electron-backscatter diffraction analysis and tensile tests suggest that asymmetric rolling increases the total imposed strain compared to symmetric rolling, and largely re-distributes the strain components due to additional shear. This enhances the intensity of grain refinement, strengthens and tilts crystallographic orientations, and increases mechanical strength. The effect is highest in the asymmetric rolling with differential roll diameters.

Potential of pharmacists to help reduce the burden of poorly managed cardiovascular risk

Introduction: Rural areas require better use of existing health professionals to ensure capacity to deliver improved cardiovascular outcomes. Community pharmacists (CPs) are accessible to most communities and can potentially undertake expanded roles in prevention of cardiovascular disease (CVD).

Objective: This study aims to establish frequency of contact with general practitioners (GPs) and CPs by patients at high risk of CVD or with inadequately controlled CVD risk factors.

Design, setting and participants: Population survey using randomly selected individuals from the Wimmera region electoral roll and incorporating a physical health check and self-administered health questionnaire. Overall, 1500 were invited to participate.

Results: The participation rate was 51% when ineligible individuals were excluded. Nine out of 10 participants visited one or both types of practitioner in the previous 12 months. Substantially more participants visited GPs compared with CPs (88.5% versus 66.8%). With the exception of excess alcohol intake, the median number of opportunities to intervene for every inadequately controlled CVD risk factor and among high risk patient groups at least doubled for the professions combined when compared with GP visits alone.

Conclusion: Opportunities exist to intervene more frequently with target groups by engaging CPs more effectively but would require a significant attitude shift towards CPs. Mechanisms for greater pharmacist integration into primary care teams should be investigated.

Calcaneal ultrasound reference ranges for Australian men and women : the Geelong Osteoporosis Study

Summary Heel ultrasound is a more portable modality for assessing fracture risk than dual-energy X-ray absorptiometry and does not use ionising radiation. Fracture risk assessment requires appropriate reference data to enable comparisons. This study reports the first heel ultrasound reference ranges for the Australian population.

Introduction This study aimed to develop calcaneal (heel) ultrasound reference ranges for the Australian adult population using a population-based random sample.

Methods Men and women aged ≥20 years were randomly selected from the Barwon Statistical Division in 2001–2006 and 1993–1997, respectively, using the electoral roll. Broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI) were measured at the heel using a Lunar Achilles Ultrasonometer. Gender-specific means and standard deviations for BUA, SOS and SI were calculated for the entire sample (men 20–93 years, n = 1,104; women 20–92 years, n = 914) and for participants aged 20–29 years (men, n = 157; women, n = 151). Associations between ultrasound measures and age were examined using linear regression.

Results For men, mean ± standard deviation BUA, SOS and SI were 118.7 ± 15.8 dB/MHz, 1,577.0 ± 43.7 m/s and 100.5 ± 20.7, respectively; values for women were consistently lower (111.0 ± 16.4 dB/MHz, P < 0.001; 1,571.0 ± 39.0 m/s, P = 0.001; and 93.7 ± 20.3, P < 0.001, respectively). BUA was higher in young men compared with young women (124.5 ± 14.4 vs 121.0 ± 15.1 dB/MHz), but SOS (1,590.1 ± 43.1 vs 1,592.5 ± 35.0 m/s) and SI (108.0 ± 19.9 vs 106.3 ± 17.7) were not. The relationships between age and each ultrasound measure were linear and negative across the age range in men; associations were also negative in women but non-linear.

Conclusion These data provide reference standards to facilitate the assessment of fracture risk in an Australian population using heel ultrasound.

"Tomorrow's car" : Deakin Universities new cross vehicle that combines the best of 2 worlds

Motorbike riders are 34-times more likely to die in a crash compared to car drivers per km travelled (1). Such safety risks together with special skill requirements for the driver and much lower comfort compared to normal cars are the main reasons why motorbikes represent only a fraction of all vehicle sales in developed countries. Deakin University is developing a revolutionary cross-over fun vehicle with ultra low fuel consumption and emissions. This new vehicle generation combines the best of two worlds: the fun to drive, low cost, and small size of a scooter together with the safety, comfort and easiness to operate of a car. The result is a vehicle that is more fuel efficient than most cars or even scooters.

Various tilting cross over vehicles have been presented over the last decade that were trying to automate the tilting control of narrow vehicles to make them safer. Examples of these concepts are the Carver, Clever and in some way also the MP3 scooter from Piaggio. The problem with fully enclosed concepts like the Carver or Clever is that they require very complex and therefore also expensive tilting control systems so that the vehicles are not price competitive compared to low cost micro cars or even normal small cars. The MP3 on the other hand comes with a tilting control system which is only semi automatic so that typical car advantages - comprehensive safety features like crush zones, roll over protection, air bags, safety belts or comfort features like full weather protection including heating and cooling – can not be provided.

Deakin’s approach is quite different to the above mentioned concepts. The requirements were derived based on two different investigations: The first step was a critical evaluation of social trends and the second step was an in-depth benchmarking study of existing concepts which identified the typical strengths and weaknesses of these concepts. In a critical next step a new concept was created that addresses most of the weaknesses of existing tilting three-wheelers in a holistic approach by setting clear priority rankings for the vehicle targets, based on current trends. The priorities were set in the following order: Safety, Affordability, Fun and Efficiency (SAFE).

The key feature that enables an enclosed tilting vehicle is a fully automatic tilting control system. With an automatic tilting control system the driver does not need to put the feet on the ground to balance the vehicle when he stops, so the vehicle can be built with a full enclosure. This allows the implementation of typical car like safety features (seat belts, roll over structure, crush zones, air bags). The SafeRide™ tilting control system is a passive system that involves the driver’s balancing sense in its feedback control system. The vehicle has typical scooter like steering characteristics, where the steering is initiated through countersteering. Another safety critical design feature is the crush zone between the two front wheels which is not possible with only one front wheel or with the powertrain positioned between the front wheels, as the powertrain can’t absorb a lot of energy due to its structural stiffness and density. The passive tilting control system is quite simple and therefore makes the vehicle very affordable, an important factor for successful commercialisation.

Another advantage of integrating the human balancing senses in the feedback control of the tilting system is that the system kicks in slightly after the human balancing reacts. In some instances that can generate the typical adrenalin thrill known from riding a bike. This fun factor is quite common with many trend sports like mountain biking, surfing, roller-skating, snowboarding, or skateboarding. Some of these sports have seen very rapid growth only a short time after they have been invented. Utilising the human balancing system during driving also makes the vehicle safer as the adrenalin is produced after reaching a semi-stable driving condition that is controlled by the vehicles tilting control system, but before the vehicle reaches an unstable driving condition that can not be controlled by the vehicle but only (eventually) by the driver – if he has got the required driving skill and if he is alert enough.

Efficiency superior to most cars and scooters is achieved by the aerodynamics of a fully enclosed body structure in combination with the small frontal area of a typical scooter and the droplet shape enabled by the relatively wide front with 2 wheels and the very narrow tail with only one rear wheel. The passive tilting system also contributes to the extreme efficiency as the system only draws some small electrical power for the electronic control unit. Another feature is a low cost exhaust energy recovery system which is discussed in another paper.

Three year follow-up of an early childhood intervention : is movement skill sustained?

Background
Movement skill competence (e.g. the ability to throw, run and kick) is a potentially important physical activity determinant. However, little is known about the long-term impact of interventions to improve movement skills in early childhood. This study aimed to determine whether intervention preschool children were still more skill proficient than controls three years after a 10 month movement skill focused intervention: ‘Tooty Fruity Vegie in Preschools’.

Methods
Children from 18 intervention and 13 control preschools in NSW, Australia were assessed at ages four (Time1), five (T2) and eight years (T3) for locomotor (run, gallop, hop, leap, horizontal jump, slide) and object control proficiency (strike, bounce, catch, kick, overhand throw, underhand roll) using the Test of Gross Motor Development-2. Multi-level object control and locomotor regression models were fitted with variables time, intervention (yes/no) and a time*intervention interaction. Both models added sex of child and retained if significant, in which case interactions of sex of child with other variables were modelled and retained. SPSS (Version 17.0) was used.

Results
Overall follow-up rate was 29% (163/560). Of the 137 students used in the regression models, 53% were female (n = 73). Intervention girls maintained their object control skill advantage in comparison to controls at T3 (p = .002), but intervention boys did not (p = .591). At T3, there were no longer intervention/control differences in locomotor skill (p = .801).

Conclusion
Early childhood settings should implement movement skill interventions and more intensively target girls and object control skills.

Beg op co-op : beggars opera co-operative

Website design. Development and identity roll out for the Beggars Opera Co-Operative

Implementation salvage experiences from the Melbourne diabetes prevention study

Background Many public health interventions based on apparently sound evidence from randomised controlled trials encounter difficulties when being scaled up within health systems. Even under the best of circumstances, implementation is exceedingly difficult. In this paper we will describe the implementation salvage experiences from the Melbourne Diabetes Prevention Study, which is a randomised controlled trial of the effectiveness and cost-effectiveness nested in the state-wide Life! Taking Action on Diabetes program in Victoria, Australia.

Discussion The Melbourne Diabetes Prevention Study sits within an evolving larger scale implementation project, the Life! program. Changes that occurred during the roll-out of that program had a direct impact on the process of conducting this trial. The issues and methods of recovery the study team encountered were conceptualised using an implementation salvage strategies framework. The specific issues the study team came across included continuity of the state funding for Life! program and structural changes to the Life! program which consisted of adjustments to eligibility criteria, referral processes, structure and content, as well as alternative program delivery for different population groups. Staff turnover, recruitment problems, setting and venue concerns, availability of potential participants and participant characteristics were also identified as evaluation roadblocks. Each issue and corresponding salvage strategy is presented.

Summary The experiences of conducting such a novel trial as the preliminary Melbourne Diabetes Prevention Study have been invaluable. The lessons learnt and knowledge gained will inform the future execution of this trial in the coming years. We anticipate that these results will also be beneficial to other researchers conducting similar trials in the public health field. We recommend that researchers openly share their experiences, barriers and challenges when conducting randomised controlled trials and implementation research. We encourage them to describe the factors that may have inhibited or enhanced the desired outcomes so that the academic community can learn and expand the research foundation of implementation salvage.

Effect of roller leveling on the bending behaviour of aged steel strip

The common grades of steel used in roll forming are: hot rolled carbon steel, high strength low alloy and recovery annealed cold rolled sheet. These steels are prone to ageing and are often skin passed and/or roller leveled to eliminate ageing as it can lead to problems in forming. In roll forming, shape defects such as bow, twist and camber are considered to be related to very small plastic strains in the longitudinal direction and hence knowledge of the material properties in the elastic plastic transition range is necessary if the process is to be modelled accurately. Previous studies with aluminium have indicated that skin pass rolling can lead to residual stresses in the strip. In this work, the study was extended to aged carbon steel and to the effect of roller leveling on both aged material and strip that had been given a light cold rolling to simulate a skin pass treatment. The results suggest that roller leveling reduced the magnitude of residual stresses resulting from skin pass rolling.

The significant differences observed between tensile and bending test results, at and near, the elastic plastic transition reinforces the need to consider bending properties when assessing the effect of prior processing on strip for roll forming.

Effect of tensile pre-strain on bending and unloading of automotive steels

In recent years, advanced high strength steels (AHSS) have been used in a wide range of automotive applications; they may have property variations through the thickness and the properties may also be dependent of prior processing including pre-straining. In order to model forming processes precisely using, for example, finite element analysis, it is important that material input data should adequately reflect these effects. It is known that shape defects in roll forming are related to small strains in material that has undergone prior deformation in a different strain path. Much research has already been performed on the change in the Young’s Modulus once a steel sheet has been plastically deformed,however many of these tests have only been conducted using tensile testing, and therefore may not take into account differences in compressive and tensile unloading. This research investigates the effect of tensile pre-straining on bending behaviour for various types of material;in bending, one half of the sheet will load and unload in compression and hence experience deformation under a reversed stress. Four different materials were pre-strained in tension with 1%, 3%, 7%, 11% and 25% elongation. Using a free bending test, moment curvature diagrams were obtained for bending and unloading. The results showed that the characteristics of the moment curvature diagram depended on the degree of pre-straining; more highly strained samples showed an earlier elastic-plastic transformation and a decreased Young's Modulus during unloading. This was compared to previous literature results using only tensile tests. Our results could influence the modeling of springback in low tension sheet operations, such as roll forming.

NGOs, pluralism and advisory services—Timor Leste

Purpose: 

24 tweets per second: a dialogue on Jorge Lorenzo’s On the Road by Jack Kerouac

Jorge Lorenzo Flores Garza’s On the Road by Jack Kerouac had its Australian premiere in July this year at the Walker Street Gallery in Melbourne. It screened as part of the ‘Outside the Outside’ series curated by Dirk de Bruyn and Glenn D’Cruz, and was introduced by Steven McIntyre.

On the Road by Jack Kerouac is the most recent work by Mexican filmmaker Jorge Lorenzo, whose previous 1/48” (2008) was listed in Cahiers du Cinéma’s top 10 most subversive films of all time. Somewhere between a book on a film, and a film of a book, Lorenzo’s work is an exact re-typing of Jack Kerouac’s On the Road, made by threading a continuous roll of 35mm negative (like Kerouac’s original scroll) through a Olivetti typewriter.

Development of an inverse routine to predict residual stresses in the material based on a bending test

Bending and reverse bending are the dominant material deformations in roll forming, and hence property data derived from bend tests could be more relevant than tensile test data for numerical simulation of a roll forming process. Recent investigations have shown that residual stresses change the material behavior close to the yield in a bending test. So, residual stresses introduced during prior steel processing operations may affect the roll forming process, and therefore they need to be included in roll forming simulations to achieve improved model accuracy. Measuring the residual stress profile experimentally is time consuming and has limited accuracy while analytical models that are available require detailed information about the pre-processing conditions that is generally not available for roll forming materials. The main goal of this study is to develop an inverse routine that determines a residual stress profile through the material thickness based on experimental pure bend test data. A numerical model of the skin passing (temper rolling) process is performed to introduce a residual stress profile in DP780 steel sheet. The skin passed strips are used in a pure bending simulation to record moment-curvature data and this data is then applied in an inverse analysis to predict the residual stress profile in the material. Comparison of the residual stress profile predicted by the inverse routine with that calculated by finite element analysis (FEA) indicates an inverse approach combined with pure bend test may present an alternative to predict residual stresses in sheet metals.