Analytic study on pure bending of metal sheets

In this work, analytical models of pure bending are developed to simulate a particular type of bend test and to determine possible errors arising from approximations used in analyzing experimental data. Analytical models proposed for steels include a theoretical solution of pure bending and a series of finite element models, based on the von Mises yield function, are subjected to different stress and strain conditions. The results show that for steel sheets the difference between measured and calculated results of the moment-curvature behaviour is small and the numerical results from the finite element models indicate that experimental results obtained from the test are acceptable in the range of the pure bending operation. Further for magnesium alloys, which exhibit unsymmetrical yielding, the algorithm of the yield function with a linear isotropic hardening model is implemented by programming a user subroutine in Abaqus for bending simulations of magnesium. The simulations using the proposed user subroutine extract better results than those using the von Mises yield function.

Comparison of bending of automotive steels in roll forming and in a V-die

Bending in a V-die has been used to indicate the outcome of bending in cold roll forming, although little direct correlation has been performed. In this work direct comparison of the springback in both processes was performed using six samples of automotive steels in a conventional roll forming line where the transverse springback is measured. A bend of similar radius was formed in a V-die and the springback determined. In general, the springback in V-die forming was greater than in roll forming, in some cases by a factor of 2. The theoretical springback angle was determined for all steels using a simple and approximate analytical equation and compared to the experimental roll forming and bending results. While for the roll forming process good agreement was achieved the theoretical values significantly underestimated springback in the V-bending process.

En-gendering the nation : gender-bending and nationalism in Miles Franklin's 'My brilliant career' and Emily Lawless's 'Grania: The story of an Island'

Writing in the lee of first-wave feminism and in an era of nation-invention, the Irish Ascendancy novelist, Emily Lawless, and the aggressively Australian Miles Franklin (of Irish, English and German extraction and coming from families who were pastoralists) wrote novels of adolescence, respectively, 'Grania: the Story of an Island' (1892) and 'My Brilliant Career' (1901). Similar and different in many ways, they both wrote as women and self-consciously inserted themselves into nation-inscribing projects with an eye to overseas readerships, and they played fast and loose with class. Curiously, both contributed to the process of transforming 'nowhere-places' into iconic nationalist places: Franklin put the Monaro on the map (a region that was a nationalist icon before the 'Red Centre' usurped its place); and Lawless wrote in ethnographic ways about the Aran Islands more than a decade before J.M. Synge tramped westward in search of the 'Peasant Quality', so beloved of the Abbey Theatre playwrights and audiences. Most compellingly, they wrote of the near-pathologies of masculinities within nationalist agendas, and of marriage and sexuality. This article examines the novels comparatively and contrastively and asks uncomfortable questions about why and how their interventions were untimely.

En-Gendering the Nation: Gender-bending and Nationalism in Miles Franklin’s My Brilliant Career and Emily Lawless’ Grania: the Story of an Island

Writing in the lee of first-wave feminism and in an era of nation-invention, the Irish ascendancy novelist, Emily Lawless, and the aggressively Australian Miles Franklin (of Irish, English and German extraction and coming from families who were pastoralists) wrote novels of adolescence, Grania: The Story of an Island (1892) and My Brilliant Career (1901) respectively. Similar and different in many ways, they both write as women, and self-consciously insert themselves into nation-inscribing projects with an eye to overseas readerships, and they play fast and loose with class. Curiously, both contributed to the process of transforming ‘nowhere-places’ into iconic nationalist places: Franklin put the Monaro on the map (a region that was a nationalist icon before the ‘Red Centre’ usurped its place); and Lawless wrote in ethnographic ways about the Aran Islanders more than a decade before Synge tramped westward in search of the ‘Peasant Quality’ so beloved of the Abbey playwrights and audiences. Most compellingly, they write of the near-pathologies of masculinities within nationalist agendas, and of marriage and sexuality. This paper examines the novels comparatively and contrastively and asks uncomfortable questions about why and how their interventions were untimely.

Lightweight stiffened composite structure with superior bending strength and stiffness for automotive floor applications

The trend towards smaller and lighter, more environmentally friendly vehicles is accelerating, as the petrol price rises and the CO2 reduction target becomes more strict. As a key enabling technology, light-weight but low-cost structure plays an important role in promoting the use of fibre reinforced polymer matrix composites in automotive applications. In this work an experimental investigiation is carried out to design, manufacture and analyse a stiffened composite structure, aiming at achieving required bending and torsional strength and stiffness at the minimum weight. One major application of this new lightweight structure is the load-bearing floor component. Some initial results from this work are presented in this paper.

Static and dynamic tests for damage identification of a slab-girder structure

Slab-girder bridges are widely used in Australia. The shear connection between reinforced concrete slab and steel girder plays an important role in composite action. In order to test the suitability and efficiency of various vibration-based damage identification methods to assess the integrity of the structure, a scaled composite bridge model was constructed in the laboratory. Some removable shear connectors were specially designed and fabricated to link the beam and slab that were cast separately. In this test, two static loads were acted in the 1/3 points of the structure. In the first stage, dynamic test was conducted under different damage scenarios, where a number of shear connectors were removed step by step. In the second stage, the static load is increased gradually until concrete slab cracked. Static tests were conducted continuously to monitor the deflection and loading on the beam. Dynamic test was carried out before and after concrete cracking. Both static and dynamic results can be used to identify damage in the structure.

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.