Increasing the amount of vitreous phase formed in the ceramic body during the liquid phase sintering process, with decreasing in its viscosity leads to the pyroplastic deformation. It sometime causes to crack, failure or rejection of ceramic parts, so the prediction and modification of these deformation is the key factor for ceramic manufacturing process. Physical and mechanical behavior of the ceramic body during sintering process including the viscose flow deformation, anisotropic shrinkage, heterogeneous densification, as well as sintering stress, have significant influence on the both final body dimensional precision and densification process. In this paper, the finite element method has been developed to study pyroplastic deformation, physical, and mechanical behavior of hard porcelain ceramic body during liquid phase sintering process. After raw materials analysis, the standard hard porcelain mixture as a ceramic body was designed and prepared. The finite element method for the ceramic specimens during the liquid phase sintering process are implemented in the CREEP user subroutine code in ABAQUS. Densification results confirmed that the bulk viscosity was well-defined with relative density. Dilatometry, SEM, XRD investigations as well as bulk viscosity simulation results confirmed that the “mullitisation plateau” was presented as a very little expansion at the final sintering stage, because of the highly amount of mullite formation.

Divergence and vorticity are two most attractive and popular quantities in the study of sever atmospheric phenomena. On the other side, the role of deformation, especially total deformation – expect for a few cases related to the frontogenesis theory – has received less attention of scientists. This study is trying to fill this gap a little. It is trying to examine the role of deformation in general and the stretching deformation, shearing deformation and total deformation in particular on precipitation. In doing so, the GFS (the Global Forecast System) wind components data in five years (2003-2005) were used to compute the stretching deformation, shearing deformation and total deformation in a network covering the Iranian and influential surrounding area.In order to evaluate the effect of the deformation field on the atmospheric variable here we used the collective 24 hours precipitation reported by the synoptic observatory around the concerned domain. Due to the irregularity of the observatories in the beginning, the reported data of the rainfall from synoptic stations were moved to regular grid points applying Cressman objective analysis method. The distribution maps of precipitation and contours of stretching deformation, shearing deformation and total deformation also were prepared.Comparison of the precipitation maps and the maps of stretching deformation, shearing deformation and total deformation in six, twelve and eighteen hours before the occurrence of precipitation, showed that in the concerned region the flux of total deformation pattern (dot product of the total deformation and the wind) was more consistent with the precipitation maps in 6 hours later. Therefore, the flux of the total deformation has a predictive value for precipitation and could be used as a precursor of precipitation.Besides the general matching of the patterns of the total deformation flux and precipitation, the location of the maximum precipitation occurrence is reasonably compatible with the location of maximum flux of total deformation in six hours earlier. In the grid points of significant values of the precipitation, the total deformation fluxes were calculated for comparison. Also for more precise investigation, the values of the cumulative rainfall were divided into three groups (0-10), (10-20), (20-30) mm and the values of the total deformation flux were computed for each of these intervals. It has been verified that the interval of 0-10 has the maximum frequency of happening regardless of value of deformation flux magnitude. The probability that precipitation occurs between 0-10 is 26%. Also the probability of occurrence of larger deformationflux decreases exponentially as the value of deformation flux increases regardless of value of precipitation.The results of the computation show that the total deformation flux is varying between 5e-5 and 10e-5 for all intervals of the three groups of rainfall. The elongation of the dilatation axis of the total deformation for all available data was computed. Based on the results of this computation the axis of dilatation in severe rain falls are elongated in the direction of West - East, Southwest - Northeast and North – South depending on the raining area and the core of maximum precipitation.

Modified human skulls are among the unique finds recovered from archaeological contexts. They exhibit various forms of deformation, which can be attributed to factors such as diseases, cultural practices, post-burial lithostatic pressure, and life history events. Particularly significant are intentionally deformed skulls, with examples, albeit in small numbers, found throughout Southwest Asia, not to mention the Iranian Plateau. However, these skulls have not received adequate attention in Iran due to problems such as focusing on other research priorities during excavations and the imbalance in the analysis of the various types of excavation findings. Examples of such skulls have been unearthed from the Neolithic sites in the Central Zagros. Recently, excavations at Tol-e Chega Sofla in the Zohreh Plain (Behbahan, Khuzestan) have yielded thirteen skull specimens with deformed proportions in a relatively well-preserved state. Hence, there is an excellent opportunity to study such skulls within the context of the Iranian Plateau. The study of the deformed skulls of Chega Sofla reveals similarities in the methods of skull deformation with the other areas of Southwest Asia. At Tol-e Chega Sofla, the practice of skull deformation using bandages is evident, along with various other traditions of cranial modification. The BG1 mass grave samples show similarities with the Ali Kosh and Seyh Hüyük skulls, while the BG6.1 specimen does not resemble any of the BG1 mass grave skulls and is similar to the modified skull of Burial no.5 in Chagha Sefid. It is worth mentioning that unintentional skull deformation, resulting in the flattening of some parts of the occipital bone, has also been observed in Chega Sofla.

The technique of precise leveling is certainly the most precise in gathering height difference observations. The main limitation of the mentioned technique is its high cost and low speed characteristics. Hence، for the purpose of repeating the precise leveling measurements (re-leveling)، which is necessary for vertical geodynamical studies، it is important to gather these observations in an optimum manner. The main purpose of this study is analyzing the characteristic features of the vertical deformation in Iran. This would assist us in concentrating the measurements in the areas that are more prone to vertical deformation as well as the analysis of vertical deformation has a priority in them. For this purpose، various kinds of data from geology، geophysics، seismology، geodesy as well as the population densities have been put together and analyzed. Result of this analysis is a new strategy to make precise re-leveling observations in Iran in a optimum way needed for vertical geodynamical studies، as a solution to the request of National Cartographic Center of Iran.

An elaborate numerical study with a validated LS-DYNA® immersed boundary method fluid-solid interaction code is used to characterize the influence of pre-detonation pressure and time duration on plastic deformation of thin steel triangular plates subjected to gaseous detonation. Other objectives of this numerical simulation such as estimation of deflection and stress contour of material at high strain rate are derived based on a strain-rate dependent Johnson-Cook material model. Simulation relies on the modeling of detonation by chemical reaction kinetic and its propagation by Conservative Element Solution Element (CESE) solver. Immersed boundary method is used to simulate the interface motion between the detonating gas and the deforming plate to facilitate the assessment of fluid pressure distribution on the plate surface. The numerical tool relates the pressure distribution and gaseous detonation parameters to the plate macroscopic deformation by employing multi-species reactive Euler’s equations for the gas and Lagrangian equation for plate. Numerical method as an appropriate tool in the evaluation of the deflection profile of the triangular plate shows that deflection decreases by the smaller size of the exposed area of the plate.

In this paper، elastic-plastic deformation of a rotating hollow FGM cylinder is analytically studied based on small strain theory and for plane-strain state. Variation of elasticity modulus، density and yield stress are assumed to obey power-law functions of radial coordinate. Material was assumed to obey Tresca yield criterion and its associated flow rule. To evaluate and validate the presented analysis، numerical results were compared with previously published results for homogeneous and also FGM cylinder with constant density and yield stress، as two special cases. Then the effect of density and yield stress variation، which was not considered in the previous researches، was investigated on the elastic-plastic deformation of the FGM rotating cylinder. The results show that when the variation of density and yield stress is ignored، considerable differences may arise not only in the magnitude of computed radial displacement and stress and strain components، but also in predicting the pattern of yield initiation and also plastic zone development.

Based on the mechanic of nanoparticles, the present research studies the deformation of cu-alumina nanocomposite experimentally and also by modeling. To optimize the deformation parameters and to control the microstructure in hot deformation process for copper-alumina nano-composites, cylindrical alumina nanoparticles samples in different percentages has been heat pressure tested. Distributions of alumina nanoparticles in copper, as well as the effects of nanoparticles on deformation have been investigated by transmission electron microscopy (TEM). To study the parameters affecting the deformation of material, the test temperatures of 350, 400, 450, 500° C and strain rates of 0.3, 0.03, 0.003 1/s have been selected. By the results of 48 experiments of stress-strain curves and to optimize the process parameters in the hot deformation, processing map is obtained for different strains. Also the hot deformation behaviors of nano-composites modeling of neural network with 4 input and one output parameters have been used. The modeling and experimental results are compared and the most optimal conditions for hot deformation of nanocomposite materials have been presented.

In this paper, asymmetric rolling process of metal sheets is investigated by method of upper bound. In analyses, the contact arches of the rolls are replaced by their chords. The material under deformation is divided into upper and lower regions separated by a line parallel to the midline of the sheet at exit. The intersection points of the chords with the mentioned line, boundary of the upper and lower regions, are selected as the origins of the cylindrical coordinate systems. Each region is divided into three deformation zones and based on the proposed velocity field presented, shear, friction, internal deformation and the total power terms are calculated. The total power is optimized with respect to the positions of the origins of the cylindrical coordinates systems and the positions of the neutral points. The results of the analysis including the required torque, rolling force and the curvature of the sheet at the exit, are compared with the analytical and experimental results of other researchers, as well as numerical simulation results obtained from Deform software. Finally, the effects of the asymmetric factors of the process, on the required torque, the rolling force and the curvature of the deformed sheet have been investigated.

In this paper, using finite element simulations and experimental results, the changes in deformation length and longitudinal strain in flexible roll forming are investigated and the relationship between them is determined. Flexible roll forming is a novel manufacturing process for producing profiles with variable cross-section. One of the important parameters of this process is the distance from the starting point of the deformation before the forming station to the central cross-section of the rolls at that station, which is called the deformation length. This parameter plays a key role in determining the distance between the forming stations and the deformation behavior of the sheet. The effect of roll diameter and mechanical properties of the sheet on the deformation length is also determined. The results showed that the maximum deformation length occurs when forming the stretching zone of the channel profile with variable cross-section, which is due to the additional tension applied to the edge due to the concave geometry of the flange in this zone. The results also showed that with increasing roll diameter and yield stress, the deformation length in all four of the stretching and compression zones and the slim and wide areas of the channel profile with variable cross-section increases, while with increasing sheet thickness, the deformation length in these zones decreases.