This paper studied the deformation mechanisms of sheet metals stamped by rigid punches and deformable dies. Emphasis was placed on the development of elastic plastic zones in the sheet workpieces, on the functions of the die parameters and on their correlations with spring-back. It was found that the reduction of spring-back was due mainly to the interface interaction offered by the dies. The p...

background: different environmental conditions, such as high temperature or exposure to some chemical agents, may affect the force decay of different methods of space closure during orthodontic treatment. the aim of this in vitro study was to evaluate the force decay pattern in the presence of tea as a popular drink in some parts of the world and two mouthwashes that are usually prescribed by t...

Japanese nickel titanium (NiTi) alloy wire possesses excellent spring-back properties, shape memory and super-elasticity. In order to adapt this wire to clinical use, it is necessary to bend as well as to control its super-elastic force, and so a direct electric resistance heat treatment (DERHT) method was developed. An electric current is passed directly through the wire, thus generating enoug...

Bending is one of the most common metal forming technology and it can be applied not only in sheet metal forming but also in forming of wires, rods, strips, pipes and bars. However, in car production, ship building and home appliance manufacturing sheet metal bending is most widely employed. One of the most significant sheet metal bending operations is V – Die bending. This process consists of ...

Muscle contractions that load in-series springs with slow speed over a long duration do maximal work and store the most elastic energy. However, time constraints, such as those experienced during escape and predation behaviours, may prevent animals from achieving maximal force capacity from their muscles during spring-loading. Here, we ask whether animals that have limited time for elastic ener...

spring back is responsible for inaccuracy of press formed sheet product. therefore, prediction of spring back is important for precise forming of stampings. to predict the amount of spring back many successful attempts have been made for simple cases such as single curved and u or v shape sheet metals. however, for more complex shapes containing double curves or double variable curved surfaces ...

Four-roll bending process is usually used for manufacturing of seamed thick-walled and thin-walled cylinders. Due to complexity of this process, the analytical solution of plate bending in this process has not been developed completely. The existence of friction and multi-step processing makes it more difficult. Investigation of four-roll bending process using analytical and numerical methods i...