The columns of frame structures are the key load-bearing components and the exterior columns aresusceptible to attack in terrorist blasts. When subjected to blast loads, the columns would suffer a loss of bearingcapacity to a certain extent due to the damage imparted which may lead to their collapse and even cause theprogressive collapse of the whole structure. The concrete-filled steel columns have been extensively used in theworld due to the existence of all suitable characteristics of concrete and steel, more ductility, increasing concreteconfinement using the steel wall, the large energy-absorption capacity and the appropriate fire behavior. In thepresent study, the concrete-filled steel square columns have been simulated under the influence of the blast loadusing the ABAQUS software. These responses have been compared for scaled distances based on the distance tothe source and the weight of the explosive material. As a result, it can be seen that although concrete deformationhas been restricted using the steel tube, the inner layer of concrete has been seriously damaged and the columndisplacement has been decreased by increasing the scaled distance. We also concluded that the concrete-filled steelcolumns have the high ductility and the blast resistance.

Intersecting cylindrical shells are frequently encountered in various types of engineering structures. Despite their common occurrence, reliable and accurate analytical methods have not been generally available, and consequently accurate design information for such configurations has also been generally lacking. To contribute to the understanding of the problem, a FINITE ELEMENT analysis is carried out for two normally intersecting cylindrical shells. Two types of loading have been applied to the structure. Results of stresses are provided, of both the outside and the inside, for the two shells. The overall agreement between the FINITE ELEMENT predictions and experimental results is a very good one. It has been shown that by using the FINITE ELEMENT method together with a "mesh generation" technique, both computational efficiency and minimum user time can be retained.      

FINITE ELEMENT Template is a new approach for constructing the stiffness matrix. In this strategy, the stiffness matrix is decomposed into the basic and higher order parts. The basic part is used to assure the convergence, and the higher order part is applied for the rank sufficiency and accuracy. The basic stiffness matrix must satisfy the rigid body and constant strain modes. On the other hand, the higher order strain modes must be applied to the higher order stiffness matrix. In fact, the constant strain modes are not considered for the higher order stiffness matrix. In this paper, the assumed natural deviatoric strain approach has been used for constructing the higher order stiffness matrix. In the template approach, the basic and higher order stiffness matrices contain some free parameters. By considering appropriate values for these parameters, a better behavior of the stiffness matrix for analyzing irregular shapes will be achieved. In this study, a bending quadrilateral ELEMENT is presented. Furthermore, some numerical examples will be solved by the suggested formulation. The results show that the proposed ELEMENT has a better behavior and lower sensitivity to mesh distortion and mesh direction in comparison to the previous presented ELEMENTs.

Let G be a , nite group and (G) = ∑,g 2 G o(g), where o(g) denotes the order of g 2 G. We show that the Conjecture 4. 6. 5 posed in [Group Theory and Computation, (2018) 59-90], is incorrect. In fact, we , nd a pair of , nite groups G and S of the same order such that (G) < (S), with G solvable and S simple.