Punching

An FMEA (Failure Mode and Effect Analysis) is a systematic method of identifying and preventing product and process problems before they occur. FMEAs are focused on preventing defects, enhancing safety, and increasing customer satisfaction. Ideally, FMEAs are conducted in the product design or process development stages, although conducting an FMEA on existing products and processes can also yield substantial benefits. FMEA is used in the manufacturing industry to improve production quality and productivity by reducing potential reliability problems early in the development cycle where it is easier to take actions to overcome these issues, thereby enhancing reliability through design. It is a method that evaluates possible failures in the system, design, process or service. In this paper, Failure mode and Effect Analysis is done on the process of Punching. A series of punching operation is done on various work pieces and the defects are found. Based on the evidence found, the ratings are given and risk priority number is given. Based on the RPN, the preventive measures are given. The FMEA is a proactive approach in solving potential failure modes. These works serve as a failure prevention guide for those who perform the punching operation and works towards effective punching operation.

ÖZET: Elektrik makinalarında kullanılan silisli stator ve rotor sac paketleri, mekanik, lazer, tel erezyon ve su jeti gibi farklı kesme yöntemleri ile kesilmektedir. Mekanik kesme yöntemi, bu yöntemler arasında maliyet açısından daha çok tercih edilmektedir. Ancak, mekanik kesme prosesi esnasında kesme kenarında plastik deformasyon ve artık gerilmeler oluşmaktadır. Oluşan bu deformasyon ve gerilmeler, silisli saclarda demir kayıplarının (histerezis ve eddy akım kaybı) artmasına ve silisli sacların manyetik özelliklerinin bozulmasına sebep olmaktadır. Mekanik kesme işleminden kaynaklanan manyetik kayıpların en aza indirgenmesi için silisli saclara gerilim giderme tavlaması yapılmaktadır. Böylelikle, silisli saclarda oluşan demir kayıpları azaltılarak manyetik özelliklerin iyileştirilmesi sağlanmaktadır. Bu çalışmada, literatürde silisli saclar üzerinde uygulanan mekanik kesme ve tavlama proseslerinin, manyetik özellikler üzerindeki etkileri ile ilgili yapılan çalışmalar araştırılarak bir arada sunulmuştur.

ABSTRACT: Stator and rotor sheet packages of silicon used in electrical machines are cut with different cutting methods such as mechanical, laser, wire erosion and water jet. Mechanical cutting process is more preferable among these cutting process in terms of cost. However, plastic deformation and residual stress consist of at the cutting edge during the mechanical cutting process. Iron losses (hysteresis and eddy) increase in due to these deformation and stresses in electrical steels and bring about degradation of the magnetic properties of electrical steels. Stress relief annealing is carried out to minimize the magnetic losses due to mechanical cutting process. Thereby, reducing iron losses (eddy and hysteresis) is provided to improve the magnetic properties. In this study, the studies related to the effects of mechanic cutting and stress relief annealing (SRA) processes on magnetic properties in literature were presented together by investigating

A non-linear three-dimensional finite element analysis, using ANSYS computer program, has been done to study the load-deflection behavior and the load-carrying capacity of a reinforced concrete flat plate built on corner columns. Material non-linearity; such as cracking and crushing of concrete, yielding of steel and plastic deformation of concrete and steel; have been included. Comparison between the results obtained by the finite element analysis and available experimental results has been made. The analytical results compared satisfactorily with the experimental ones.

Existing solid slab bridges under a combination of wheel loads and distributed traffic loads sometimes do not fulfil the code requirements for shear. However, reinforced concrete slabs loaded close to the support are subjected to shear stresses which might result in a failure mode of combined punching and shear. This behaviour is studied in a first series of experiments on slabs under a concentrated load close to the support, and these experiments resulted in a set of recommendations. To verify if these recommendations can be used when assessing solid slab bridges under distributed and concentrated loads, slabs under a combination of a line load, representing the dead weight, and a concentrated load, representing a wheel load, are tested up to failure. The experimental results are used to assess the ultimate shear which can be carried at the support and the influence of the varied parameters is discussed. The results demonstrate how different types of loading such as dead loads and ...

In North America and much of the world, fiber–reinforced–polymer (FRP) reinforcing bars have emerged as an innovative solution to overcome the corrosion problem in concrete structures. Most investigations in the past have focused mainly on the behavior under static– loading conditions, omitting seismic design. Therefore, the feasibility of using FRP as internal reinforcement in a completely reinforced–concrete (RC) structure immune to corrosion essentially pertains to its strength, stiffness, and deformation capacity to resist seismic loads, has become questionable. Nevertheless, no tests have been conducted yet on FRP–RC slabcolumn connections subjected to a combination of gravity and lateral reversed cyclic loads. It should, however, be pointed out that the current North American codes and guidelines [CSA S806 (2012) and ACI 440.1R (2015)] do not include any requirements concerning the nominal punching–shear strength, stiffness, or drift capacity of flat–plate structures reinforce...

Reinforced concrete (RC) flat slabs supported on columns are one of the most widely used structural systems for office and industrial buildings. In regions of medium to high seismic risk RC walls are typically added as lateral force resisting system and to increase the lateral stiffness and strength. Although slab-column connections possess low stiffness and do not contribute substantially to the lateral resistance of the structure, each connection must have the capacity to follow the seismically induced lateral displacements of the building while maintaining the capacity to transfer the vertical loads from the slab to the columns. Otherwise brittle punching failure of the slab occurs and the deformation capacity of the connection determines the deformation capacity of the entire building. This article presents an analytical model to account for the hysteretic behaviour and cumulative damage effects on the moment-rotation relationship of internal slab-column connections without transverse reinforcement when subjected to cyclic loading. The developed model is an extension of a mechanical model proposed earlier by the authors for monotonic loading conditions. The cyclic model assumes that a fixed shear crack governs the behaviour of the slab-column connection and adopts a hysteretic moment-curvature relationship for the radial direction. The main assumptions of the model are based on local deformation measurements from tests. Seismic damage is introduced through a non-cumulative model proposed by others. The model performance is assessed through comparison to tests performed by the authors. The cyclic model predictions are in good agreement with the experimental results and provide higher accuracy than the monotonic model with respect to both the local behaviour and the global behaviour.

Punching in slabs is usually associated to the application of concentrated loads or to the presence of columns. One of the main concerns related to flat slabs is its punching shear capacity at slab column connection. Provided that bending capacity is installed, punching shear failure is hence characterized by the development of a truncated cone shaped surface at the slab-column connection. Frequently, there is the need to strengthen existing flat slabs against punching shear failure. One of the strengthening practices, which have been tested within current experimental programmer, consists on gluing carbon fibre reinforced polymers on concrete surface. Moreover, we want to know the behaviour of RC flat slab under FRP material against punching shear. The effect of FRP bars against punching shear is checked.The objective of the current study was to explain the feasibility of RC flat slab to examine the application of steel rods, FRP rebar on the improving of punching shear. Extensive applications of the fiber-reinforced polymer (FRP) as new construction materials have been recently accomplished. FRP materials are lightweight, high strength, and no-corrosive materials. By virtue of these advantages, there is a wide range of recent, current, and potential applications of these materials that covers both new and existing structures. Among different types of FRP materials, a fiber-reinforced polymer (FRP) is used extensively in the structural engineering field. This study was carried out to examine the viability of using FRP bars for the punching shear strengthening of slab.