Assumed strain finite element for natural frequencies of bending plates

Purpose This paper aims to describe the formulation of a new finite element by assuming the strain field rather than the displacement field and by using the Reissner–Mindlin plate theory for the free vibration analysis of bending plates. This quadrilateral element consists of four-nodes and twelve degrees of freedom. The suggested element is based on assumed functions of the strain field that satisfy the compatibility equation. Design/methodology/approach After the proposition of the new element, several numerical tests for plates with regular and distorted meshes are presented to assess the performance of the new element. In addition, a parametric study is carried out to analyze the effects of biaxial loads on the natural frequencies of square plates with various boundary conditions. Detailed discussions are proposed after each benchmark problem. Findings The formulated element has verified the shear locking test and passes the patch test. The obtained results from the developed element show an excellent accuracy and fast convergence, and the natural frequencies are in excellent agreement when compared with analytical and other available numerical solutions. Originality/value The present element is simple in its formulation and has been proven to be applicable to thin or thick plate situations with sufficient accuracy. This element with full integration is free from shear locking, however, the numerical results provided by the standard four-node plate element R4 element show locking phenomena in thin plates. In addition to these features, the imposition of the compatibility conditions and the rigid body modes allow obtaining a finite element with higher-order terms for displacements field, which can increase the performance of the finite elements.

Bistable Threshold Humidity Sensor Switch with Rectangular Bimorph Bending Plate

Energy-autonomous bistable threshold sensor switches have the potential to reduce costs because they do not need any electrical energy supply for monitoring physical quantities, such as relative humidity. In previous work, a bistable beam-like sensor switch with switching hysteresis was manufactured from sheet metal and a partially coated water vapor-sensitive hydrogel (poly(vinyl alcohol)/poly(acryl acid)). Based on the beam theory, a corresponding mechanical model was developed. However, bending plates should be used instead of bending beams to separate the humidity to be measured from the electrical contacts. For this reason, this work deals with the development and realization of a mechanical model based on the plate theory to describe the deflection of a silicon bimorph bending plate partially coated with hydrogel that swells with increasing humidity. For implementing a switching hysteresis a plasma-enhanced chemical vapor deposition silicon dioxide (SiO2) layer is used, which was deposited and structured on top of the silicon plate. The hydrogel layer itself is patterned on the surface of the bending plate using a stamp technique. To validate the mechanical model, the switching hysteresis of the miniaturized sensor switch was measured optically by a camera measurement device.

Effect of Spring Back on Formation Process of Sheet Metal Bending Plates

This study aims to observe the amount of deviation that occurs due to the influence of spring back on the forming process. spring back in question is the back force when the plate undergoes a forming process, but when the load is released, the plate condition will reverse or return to its initial condition. This reversal is due to the factor of the elasticity of the material that is owned. Other factors that influence the bending process include thickness, width, angle of bending and others. object of this research is a sheet metal plate with a thickness of 1 mm - 4 mm. Forming process is done by bending process. This bending process is widely used in the plate forming process, namely to bend the sides of the plate to make it stiffer. This bending process is carried out in cold conditions where the process is carried out at room temperature. This research was conducted by preparing slices of the same width and length and then the process of bending them to form an angle of 20 ° to 120 °. results of this test indicate that the thicker the bent material has the tendency to produce small deviations. This means that the value of the spring back ratio also decreases. The value of the spring back ratio in this study ranges from 1% to 9%. This means that if the bending process is carried out on a steel plate with the resulting bending angle of 90 °, the bending angle of the shoe must be more than 90 °, the excess is 1 ° - 9 °. So that when the load is released, the position of the susdut bends closer to 90 °.

Desain dan Analisis Alat Bending V Sistem Hidro Pneumatik

The design of the pneumatic hydro system V bending tool serves as an alternative tool for bending plates replacing the manual bending method which is widely used in the industrial community, especially machining workshop workshops today. In this design the hydraulic jack bender is driven by a pneumatic cylinder so that the workload of the operator is lighter. As for the results of this design and analysis, a V bending tool with 750 mm frame height, 650 mm frame width, 150 mm hydraulic stroke length, and 5 mm diameter spring pull wire are obtained. In addition, the punch angle is 85o and the punch radius is 1.5 mm while the die angle is 85o, the width of the V die is 33 mm and the bending line capacity is 300 mm. The punch and die material chosen is steel AISI 1045.

Application of the successive approximation method to the analysis of bending plates

This work presents an algorithm for calculating the bending plates of medium thickness according to the Reissner’. To obtain numerical results, the method of successive approximations (MSA) is used. This method has high accuracy and fast convergence, which was confirmed by the solution of a range of tasks. Publication of the results of the calculation of plates of medium thickness with the boundary conditions revised here is supposed to be in the following articles.