Analysis on development of incremental ring rolling process

Öztop, Muin Süleyman
In this study, a novel incremental ring rolling process used in production of rings with various cross sections is examined. A basic type of this process is investigated numerically, using commercial finite element programs; MSC Superform, MSC Marc. The user defined subroutines are also utilized for flexibility in modeling. The aim of modeling is to determine the material flow for geometrical analysis, strain/stress distribution for tool force analysis and residual stresses, in a cost effective way. The process has instabilities and requires large number of incremental stages to complete a full finite element simulation. The full models are reliable but costly hence the numerical studies are focused on reliable simplified models with lower computation time. Different approaches are developed: three-dimensional segment model, improved segment model, velocity coupling model. The results of these models are compared with experimentally verified full models. Numerical parameters such as mesh type, step size, convergence ratio are examined. After verification of the model different applications to of the process is developed and physical parameters affecting the process are discussed; such as the tool path .


Simulations for a novel magnetic resonator with V-shaped structures
Ekmekci, Evren; Sayan, Gönül (2007-01-01)
It is demonstrated in this paper that a novel structure which consists of V-shaped conducting strips may exhibit magnetic resonance effect similar to the split ring resonator structures. The simulations have been done using Ansoft HFSS v9.2. By applying a time varying electric field to the V-shaped structure, the location of the resulting resonant frequency has been determined and furthermore, the dependency of resonance frequency on arm width, arm angle, and dielectric thickness have been investigated.
Cutting edge: Role of toll-like receptor 9 in CpG DNA-induced activation of human cells
Takeshita, F; Leifer, CA; Gursel, I; Ishii, KJ; Takeshita, S; Gürsel, Mayda; Klinman, DM (The American Association of Immunologists, 2001-10-01)
Unmethylated CpG motifs present in bacterial DNA stimulate a rapid and robust innate immune response. Human cell lines and PBMC that recognize CpG DNA express membrane-bound human Toll-like receptor 9 (hTLR9). Cells that are not responsive to CpG DNA become responsive when transfected with hTLR9. Expression of hTLR9 dramatically increases uptake of CpG (but not control) DNA into endocytic vesicles. Upon cell stimulation, hTLR9 and CpG DNA are found in the same endocytic vesicles. Cells expressing hTLR9 are ...
Potential role of phosphatidylinositol 3 kinase, rather than DNA-dependent protein kinase, in CpG DNA-induced immune activation.
Ishii, KJ; Takeshita, F; Gursel, I; Gürsel, Mayda; Conover, J; Nussenzweig, A; Klinman, DM (Rockefeller University Press, 2002-07-15)
Unmethylated CpG motifs present in bacterial DNA stimulate a strong innate immune response. There is evidence that DNA-dependent protein kinase (DNA-PK) mediates CpG signaling. Specifically, wortmannin (an inhibitor of phosphatidylinositol 3 kinase [PI3]-kinases including DNA-PK) interferes with CpG-dependent cell activation, and DNA-PK knockout (KO) mice fail to respond to CpG stimulation. Current studies establish that wortmannin actually inhibits the uptake and colocalization of CpG DNA with toll-like re...
3d modeling of on-chip acoustophoretic particle manipulation in a polymer microfluidic device
Çaǧatay, E.; Özer, Mehmet Bülent; Çetin, B. (2016-01-01)
This study focuses on understanding of the sensitivities of the acoustophoretic process on uncertainties/errors in the geometric properties of the chip material and the piezoelectric actuators. The sensitivity of the acoustophoretic process is investigated both numerically and experimentally. For the numerical simulations a three dimensional finite element model is used. In the experimental analysis, a microfluidic chip with two stations is used. The first station has the accurate geometric values of the de...
Artificial neural network estimator design for the inferential model predictive control of an industrial distillation column
Bahar, A; Özgen, Canan; Leblebicioğlu, Mehmet Kemal; Halıcı, Uğur (2004-09-15)
An inferential control methodology, that utilizes an artificial neural network (ANN) estimator for a model predictive controller (MPC), is developed for an industrial multicomponent distillation column. In the control of product compositions by a feedback control system, because of the difficulty of on-line measurements of compositions, temperature measurements can be utilized. The selection of the temperature measurement points for the inferential control is done by the help of singular value decomposition...
Citation Formats
M. S. Öztop, “Analysis on development of incremental ring rolling process,” M.S. - Master of Science, Middle East Technical University, 2006.