A new metallic energy dissipation system for steel frame based on negative Poisson’s ratio structures

Milad Masoodi,Ahmad Ganjali,Hamidreza Irani,Aboozar Mirzakhani 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.1

Using negative Poisson’s ratio materials, an innovative metallic-yielding damper is introduced for the first time in this study. Through the use of ABAQUS commercial software, a nonlinear finite element analysis is conducted to determine the performance of the proposed system. Mild steel plates with elliptical holes are used for these types of dampers, which dissipate energy through an inelastic deformation of the constitutive material. To assess the capability of the proposed damper, nonlinear quasi-static finite element analyses have been conducted on the damper with a variety of geometric parameters. According to the results, the proposed system is ductile and has a high capacity to dissipate energy. The proposed auxetic damper has a specific energy absorption of 910.8 J/kg and a ductility of 33.6. Therefore, this damper can dissipate a large amount of earthquake input energy without buckling by increasing the buckling load of the brace with its ductile behavior. In addition, it was found that by incorporating auxetic dampers in the steel frame, the frame was made harder, stronger, and ductile and its energy absorption increased by 300%.

Nonlinear Dynamic Analysis and Natural Frequencies of Gabled Frame Having Flexible Restraints and Connections

Amir R. Masoodi,Sina Heyrani Moghaddam 대한토목학회 2015 KSCE Journal of Civil Engineering Vol.19 No.6

Nonlinear dynamic and natural frequencies of a gabled frame with elastic restraints and semi-rigid connections are investigated by using a program in OpenSees software. Natural frequencies are obtained for two states, which are flexible connections and semi-rigid supports, separately. The mode shapes of structure are also obtained for the described states. Also, the effect of connection flexibility on the dynamic responses of the frame is obtained for different values of peak ground acceleration. The members of this structure are modeled as a nonlinear beam-column element. The members of structure are assumed to be prismatic. Two equal lumped masses at the head of two columns in horizontal and vertical directions are considered as the mass pattern of structure. Note that three degrees of freedom are allocated to all nodes. Furthermore, the mode shapes of frame are obtained. Conclusively, the effects of semi-rigid connections and supports on the natural frequencies and mode shapes of structure are investigated. As results, the top level displacement and base shear responses of frame are reported.

Spent Wheat Straw Compost of Agaricus bisporus Mushroom as Ruminant Feed

Fazaeli, H.,Masoodi, A.R. Talebian Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.6

Spent compost wheat straw is an available by-product from edible mushroom production, which constitutes a potential pollutant and is cost effective for disposal. This study was conducted to determine the nutritive value as ruminant feed of spent wheat straw compost from Agaricus bisporus mushroom production. The compost was provided from a mushroom farm, the casing soil was removed from the whole compost, and then it was sun dried and sampled for chemical analysis. An experiment was conducted, in which four wheat straw-based diets comprising control (I), 10% spent straw (II), 20% spent straw (III) and 30% spent straw (IV) were tested in a cross-over design using 8 sheep. Dry matter intake (DMI) was 74.0, 73.8, 70.2 and 57.1 and organic matter intake (OMI) was 62.7, 63.4, 58.0 and 44.4 g per kg $BW^{0.75}$ for diets I, II, III and IV, respectively, which, were significantly (p<0.05) lower for diet IV. Digestible OMI was respectively 33.1, 32.6, 30.6 and, 20.2 g per kg $BW^{0.75}$ on the four diets which were significantly (p<0.05) different between the treatments. Inclusion of spent compost straw up to 20% of the diet did not affect the digestibility of DM, OM, CF, ADF and NDF, but the diet containing 30% compost straw had statistically (p<0.05) lower digestibilities. Nitrogen balance was also significantly (p<0.05) different between the treatments.

Oil Biosynthesis and its Related Variables in Developing Seeds of Mustard (Brassica juncea L.) as Influenced by Sulphur Fertilization

Fazili, Inayat S.,Masoodi, Muzain,Ahmad, Saif,Jamal, Arshad,Khan, Jafar S.,Abdin, Malik Z. 한국작물학회 2010 Journal of crop science and biotechnology Vol.13 No.1

NONDIFFERENTIABLE SECOND ORDER SELF AND SYMMETRIC DUAL MULTIOBJECTIVE PROGRAMS

Husain, I.,Ahmed, A.,Masoodi, Mashoob Korean Society of Computational and Applied Mathem 2008 Journal of applied mathematics & informatics Vol.26 No.3-4

In this paper, we construct a pair of Wolfe type second order symmetric dual problems, in which each component of the objective function contains support function and is, therefore, nondifferentiable. For this problem, we validate weak, strong and converse duality theorems under bonvexity - boncavity assumptions. A second order self duality theorem is also proved under additional appropriate conditions.

MIXED TYPE SECOND-ORDER DUALITY WITH SUPPORT FUNCTION

Husain, I.,Ahmed, A.,Masoodi, Mashoob The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.5

Mixed type second order dual to the non-differentiable problem containing support functions is formulated and duality theorems are proved under generalized second order convexity conditions. It is pointed out that the mixed type duality results already reported in the literature are the special cases of our results.

Elastoplastic nonlinear behavior of planar steel gabled frame

Moghaddam, Sina Heyrani,Masoodi, Amir R. Techno-Press 2019 Advances in computational design Vol.4 No.4

In this paper, static nonlinear analysis of gable frame is performed using OpenSees software. Both geometric and material nonlinearities are considered in analyses. To consider large displacements, co-rotational coordinate transformation is used in software. The effects of symmetric and asymmetric support conditions including clamped and simple supports are studied. On the other hand, the material nonlinearity is reflected on analyses using Giuffre-Menegotto-Pinto steel material. Note that strain hardening characteristics are also considered in this model. Moreover, I-shaped cross-section is assumed for all members. The results are provided for different geometry properties of gable frame including shallow and deep inclined roof. It should be added that buckling and post-buckling behaviors of gable frame are investigated using related equilibrium paths. A comparison study is also implemented on the responses of buckling loads obtained for different support and geometry conditions. To trace snap-through paths completely, a displacement control method entitled arc-length is utilized. Findings show the capability of proposed model in nonlinear analysis of gable frames.

Static analysis of functionally graded non-prismatic sandwich beams

Rezaiee-Pajand, M.,Masoodi, Amir R.,Mokhtari, M. Techno-Press 2018 Advances in computational design Vol.3 No.2

In this article, the static behavior of non-prismatic sandwich beams composed of functionally graded (FG) materials is investigated for the first time. Two types of beams in which the variation of elastic modulus follows a power-law form are studied. The principle of minimum total potential energy is applied along with the Ritz method to derive and solve the governing equations. Considering conventional boundary conditions, Chebyshev polynomials of the first kind are used as auxiliary shape functions. The formulation is developed within the framework of well-known Timoshenko and Reddy beam theories (TBT, RBT). Since the beams are simultaneously tapered and functionally graded, bending and shear stress pushover curves are presented to get a profound insight into the variation of stresses along the beam. The proposed formulations and solution scheme are verified through benchmark problems. In this context, excellent agreement is observed. Numerical results are included considering beams with various cross sectional types to inspect the effects of taper ratio and gradient index on deflections and stresses. It is observed that the boundary conditions, taper ratio, gradient index value and core to the thickness ratio significantly influence the stress and deflection responses.

Pushover analysis of gabled frames with semi-rigid connections

Ahmad Shooshtari,Sina Heyrani Moghaddam,Amir R. Masoodi 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.6

The nonlinear static analysis of structure, which is under the effect of lateral loads and provides the capacity curve of the structure, is defined as a push-over analysis. Ordinarily, by using base shear and the lateral displacement of target point, the capacity curve is obtained. The speed and ease of results interpretation in this method is more than that of the NRHA responses. In this study, the nonlinear static analysis is applied on the semi-rigid steel gabled frames. It should be noted that the members of this structure are analyzed as a prismatic beam-column element in two states of semi-rigid connections and supports. The gabled frame is modeled in the OpenSees software and analyzed based on the displacement control at the target point. The lateral displacement results, calculated in the top level of columns, are reported. Furthermore, responses of the structure are obtained for various support conditions and the rigidity of nodal connections. Ultimately, the effect of semi-rigid connections and supports on the capacity and the performance point of the structure are presented in separated graphs.

Mixed type second-order duality with support function

I. Husain,A. Ahmed,Mashoob Masoodi 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.5

Mixed type second order dual to the non-differentiable problem containing support functions is formulated and duality theorems are proved under generalized second order convexity conditions. It is pointed out that the mixed type duality results already reported in the literature are the special cases of our results. Mixed type second order dual to the non-differentiable problem containing support functions is formulated and duality theorems are proved under generalized second order convexity conditions. It is pointed out that the mixed type duality results already reported in the literature are the special cases of our results.