Precast prestreesed concrete braces are a new method for seismic strength of Concrete Structures which has the following benefits: a) no wet concrete work in construction site b) no bolt or anchorage to the existing frame c) easy to apply d) short construction period e) low construction cost; to evaluate seismic performance of strengthened structure. A model consist of existing frame and concrete braces were created using ABAQUS (nonlinear-finite element) software. Comparison existing and strengthened frame showed that braces are effective in lateral drift decreasing. Study concrete compressive strength on seismic behavior of brace showed that when compression strength of brace is lower than existing frame; retrofitting system has low stiffness and wasn’ t effective in reducing lateral drift. But, in specimen with compressive strength ratio (brace to frame) two times or more, braces showed high strength and stiffness.

Mechanical damages in the processes of harvest and post-harvest form the most important causes of loss in Cucurbits. They cause tissue destruction and consequent fruit’s decay. Because of the difference between the mechanical strength of cantaloupe flesh vs. that of the skin of cantaloupe, internal bruising’s constitute the more usual damages with no visibility. This type of injuryis hard to predict through analytical methods. Throughout the present study,the mechanical properties of skin vs. flesh were determined through individual experiments and then Finite Element Model (FEM) was developed through ABAQUS software. The applied displacements on the model were equal to 5.5, 11 and 16.5 mm or 10, 20 and 30% of the final deformation, respectively. The analytical results showed that the internal tissue of fruit reached the yield point at 20%of whole displacementor in 90N force, with the internal failure occurring as not visible on the surface of the fruit. The model was verified by a comparison of force-displacement graph from the experimental data and FEM results. A high correlation (R2=0.983) between the predicted vs. the actual force indicated the validity in use of FEM model.

Summary: Recent development in Extended Finite Element Method (XFEM) opened new avenues thorough crack propagation problems. However, it ability to predict crack path in micro scale medium of a real porous rock is questionable. In this work, we compare two strategies and introduce one as the best strategy to use the XFEM for such a purpose in ABAQUS Software. We demonstrate our claim by comparing numerical results with analytical solution and experimental test. Introduction: Crack growth has always been one of the major challenges in the rock mechanics. Although pores, joints and fractures are the most critical structures controlling cracks initiation and propagation, their spatial distribution and geometrical effects are not still well-understood. In this study, we aim to numerically model the crack growth in a real porous rock. Methodology and Approaches: We use the extended finite element method (XFEM), which has recently attracted more attentions due to its ability to estimate the discontinuous deformation field by using special shape functions. Since direct use of the XFEM does not lead to an accurate result, two different strategies are considered for applying the XFEM on a porous model to simulate the crack propagation. Results and Conclusions: Our results showed that applying several different partitions and enrich them individually lead more logical results than to allocate reduced elastic modulus to porosity. We used this strategy to evaluate the XFEM both analytically and experimentally as a possible numerical solution. Thus, two simple models were constructed, both numerically and experimentally (Granite): i. a sample with one void and one crack, and ii. a sample with two voids and one crack between them. Analytical solutions for the stress intensity factor revealed that the XFEM modeling can compute this parameter with an error less than 5%. On the other hand, experimental results showed that the XFEM with partitioning strategy can predict the correct crack growth path comparative to the experimental results. Accordingly, digital images of Berea sandstone were used as a real reservoir rock and, then, this method was implemented to simulate multi-crack propagation through the exact medium of rock.

Composite steel plate shear wall is usually made up of a steel plate and also a reinforced concrete cover, which is attached to one side or both sides of the plate by means of a shearing device. In innovative composite steel plate shear wall system, a gap is created between concrete cover and boundary beams and columns. The presence of this gap in small earthquakes does not cause the concrete to interfere with the frame and thus prevent its failure. In relatively large quakes, this distance between the concrete wall and the boundary members is closed and added to the resistance of the system. In this paper, steel plate, concrete cover and frame were separated to calculate the strength of composite steel plate shear wall by their interaction. To evaluate the effect of concrete strength on composite steel plate shear wall strength, the gap between concrete cover and boundary members has been discussed, and then two relationships have been proposed to calculate the strength of composite steel plate shear wall. For this purpose, this paper has been used for analyzing pushover. In order to verify the numerical modeling, the characteristics of a steel plate shear wall model, composed of a laboratory study by Arabzadeh and colleagues at Tarbiat Modares University in 2011On the behavior of composite steel plate shear walls, it has been selected.

In Portland Cement Concrete (PCC) pavement of the roads, dowels bar transfers vehicle loading to the unloaded slab. Load Transfer Efficiency (LTE) is used to evaluate dowel bars in PCC pavement. This parameter is defined as the vertical displacement ratio of the loaded slab versus the unloaded slab. In this study, the impact of effective factors (friction coefficient between dowel and concrete slab, wheel loading, dowel diameter and dowel spacing) on load transfer efficiency was studied with modeling by using the ABAQUS finite element software. The verification process was presented to increase confidence in model results and the response data from the numerical simulation agrees well with analytical solution. The results show that with increasing the friction coefficient between slab and dowel, load transfer efficiency increases but the failure of concrete around dowel bars was found to initiate at the face of joint. Furthermore, if strains remain in elastic range, increasing in wheel loading magnitude does not lead to reduce load transfer efficiency but dowel diameter or its spacing have an important role on load transfer by dowels.

The use of concrete in combination with steel in structures can play an important role in improving the structural behavior, ie increase in strength and formability. In many cases, in steel structures that do not meet the considerably shaping criteria. In this study, a solid concrete beam and steady steel beams were modeled using ABAQUS finite element software and verified by a laboratory model. In the following six groups, the difference in specimens was only in the manner of connecting concrete to steel, and for each of the six series, five different thicknesses were considered and investigated, which resulted in the following conclusions. Increasing the number of cutters increases the resistance of composite beams. By increasing the number of simple cut-offs into two rows, 10% of the final bending strength of the composite beams increases. The difference between the studs and the corners is not significantly different. The effect of simple cut-offs and L shapes has been around 2%.

Afinite element model is developed for simulation of the curing process of a thick axisymmetric rubber article reinforced by metal plates during the molding and cooling stages. The model consists of the heat transfer equa- tion and a newly developed kinetics model for the determination of the state of cure in the rubber. The latter is based on the modification of the well-known Kamal-Sourour model. The thermal contact of the rubber with metallic surfaces (inserts and molds) and the variation of the thermal properties (conductivity and specific heat) with temperature and state-of-cure are taken into consideration. The ABAQUS code is used in conjunction with an in-house developed user subroutine to solve the governing equations. Having compared temperature profile and variation of the state-of-cure with experimentally measured data, the accuracy and applicability of the model is confirmed. It is also shown that this model can be successfully used for the optimization of curing process which gives rise to reduction of the molding time.

Hydrogen has become an attractive source of energy for transportation industry, which is adaptable to the environment. Using composite pressure vessel type IV for storing compressed hydrogen gas seems to be a safety solution because of their ratio of strength to weight. Type IV composite pressure vessels consist of three main parts of polymeric liner, metallic boss and carbon fiber/epoxy composite shell. In the dome zones of these vessels, the thickness of composite layers and the fiber angle would increase because of accumulation of resin and reduction in radius. This issue is caused the modeling of these vessels to be a serious challenge. The WCM plug-in is presented for simulation of axisymmetric or three-dimensional composite pressure vessels type III and IV in ABAQUS software. In addition to the parameters like layer thicknesses and fiber angles, manufacturing parameters such as bandwidth, transition angle and end fraction could be also defined in this plug-in in order to achieve more accurate results. In this study, a type IV high pressure composite vessel with inner volume of two liters is modeled using the WCM plug-in in ABAQUS software. Numerical results are assessed by the available experimental results in the literature. Moreover, failure pressure of this vessel has been estimated by calculating the on-axis stresses and using failure criteria such as Tsai-Hill, Tsai-Wu and Hashin which is not done in other investigations.

The bicycle helmet has a significant role in reducing and preventing impact because of reducing the deceleration of the skull, spreading the area over which the forces of the impact reach them and preventing direct contact between the skull and the impacting object. Honeycomb structure, due to its elastic properties, extends the energy absorption time of the whole structure and also increases the ability of the whole structure to absorb energy. Therefore, it can be used in the liner designing of a helmet to reduce velocity, energy, and acceleration in impacts. In this paper, intending to identify the minimum stress transmitted to the helmet during an impact, we used Rhino software to model a helmet with honeycomb liner and outer shell and then analyzed it in ABAQUS software. Due to the fact that the size of various parts of the head is different in people, so for more comfort and safety, the use of customized-helmet is emphasized. To design and make a customized-helmet, the materials used in designing the helmet are ABS and PETg filaments, which can be used in 3D printing. These two materials have been analyzed with four compositions for the liner and the shell of the helmet. The results show that the best combination of the helmet with Minimum stress transmission and appropriate plastic strain due to impact is the helmet case with honeycomb liner of PETg and a shell made of ABS.