In the current study, two solution strategies were used to solve the nonlinear equations that resulted because the material nonlinear response was considered. ABAQUS/Standard performs an implicit solution which needs a huge number of iterations and/or increments to avoid divergence problems and a premature solution abortion. Due to the time required to perform the implicit solution, a quasi-static solution can be introduced using ABAQUS/ Explicit solver, which is used for dynamic problems. It is possible to consider the static loading case as a dynamic loading with a long duration. In other words, if the inertia forces’ effects caused by the mass can be eliminated, the solution will be a quasi–static solution. This can be achieved in ABAQUS/ Explicit by monitoring the Kinetic Energy (EKE = ALLKE), which should be negligible and should not exceed 1 – 5 % of the Internal Energy (EI = ALLIE). ABAQUS/Explicit solves problems without iterations by using the kinematic state, depending on the previous increment, and in this way the computations will be reduced significantly.
Earlier works cited in the literature review in chapter 2 and in section 3.2.2 concerning the numerical modelling of hybrid joints are restricted to two dimensional analysis. This is the first time that a three dimensional analysis of a hybrid joint is attempted taking into account of the complicated shape & geometry of the joint, bonding of dissimilar materials, eccentricity in the load path and the interfacial stresses. Therefore, a three dimensional FE model of a hybrid composite-steel joint is generated and analysed for different set of loading cases: in-plane compression loading, 4-point loading and the flexural load. Numerical and experimental stiffness were to be found in good correlation up to linear region for the static compression analysis. Linear elastic analysis of the joint under the in-plane loading has shown that the normal stress is not uniform across the width of the joint. Researchers like Wright et. al., (2000) and Boyd et. al., (2004) have reported that normal and shear stresses are concentrated in the interface layer where GRP-Steel-Balsa core are bonded for the case of in-plane compression loading. Additionally, this three dimensional analysis has resulted in further understanding that the normal stress is more concentrated along the middle of the joint and decreases towards the free edge. It can be said that this reduction of stresses towards the free surface is a similar phenomenon of ’anticlastic’ effect normally seen in a single lap joint. It is observed that the critical stress values are invariably concentrated around the ’critical zone’ and remains the main source of failure initiation for all the loading scenario. However, it is to be noted that the normal and shear stress components are dominant for the in-plane compression loading case while the axial bending stress component initiates failure when the joint is subjected to out-of-plane loading. Predicted failure mechanisms deduced from the numerical model reflect the damage seen in the hybrid joint specimen.
The shear capacity of deep beams is a major issue in their design. The behavior of reinforced concrete deep beams is dif- ferent from that of slender beams because of their relatively larger magnitude of shearing and normal stresses. Unlike slen- der beams, deep beams transfer shear forces to supports through compressive stresses rather than shear stresses. There are two kinds of cracks that typically develop in deep beams: ﬂexural cracks and diagonal cracks. Diagonal cracks eliminate the inclined principal tensile stresses required for beam action and lead to a redistribution of internal stresses so that the beam acts as a tied arch. The arch action is a func- tion of a/d (shear span/depth) and the concrete compressive strength, in addition to the properties of the longitudinal reinforcement. It is expected that the arch action in FRP rein- forced concrete would be as signiﬁcant as that in steel rein- forced concrete and that the shear strength of FRP- reinforced concrete beams having a/d less than 2.5 would be higher than that of beams having a/d of more than 2.5 . The application of the reinforced concrete deep beams within structural engineering practice has risen substantially over the last few decades. More specially, there has been an increased practice of including deep beams in the design of tall buildings, offshore structures, wall tanks and foundations. They differ from shallow beams in that they have a relatively larger depth compared to the span length. As a result the strain distribution across the depth is non-linear and cannot be described in terms of uni-axial stress strain characteristics . Prediction of behavior of deep beams by design codes which contain empirical equations derived from experimental tests has some limitations. They are only suitable for the tests con- ditions they were derived from, and most importantly, they fail to provide information on serviceability requirements such as structural deformations and cracking. Likewise, the strut and tie model, although based on equilibrium solutions thus pro- viding a safe design, does not take into account the non-linear material behavior and hence also fails to provide information on serviceability requirements. Cracking of concrete and yielding of steel are essential features of the behavior of
Ibrahim G. et al. (4) 2018 presented a study on the seismic performance of exterior beam-columnjoints in building frames strengthened by Ferro-cement using nonlinearfiniteelementanalysis. The parametric studied variables were the level of axial loading on the column, compressive strength of specimens, percentage of longitudinal reinforcement in the beam, and orientation of expanded wire mesh in Ferro-cement layer, for specimens strengthened by different number of Ferro-cement layers. ANSYS was used for Non linear finiteelementanalysis. While analyzing basic idealization were carried out. The test beam-to-column joint specimens were typically discretized using 3-D isoperimetric 8-node solid elements; Solid65. The element “Solid65” was adopted to model the concrete and Ferro-cement layers to simulate cracking in tension and crushing in compression. The comparison between experimental and numerical results carried out and the analysis indicated formation of flexural cracks in the test specimens at low levels of displacements ranging between 1.6mm and 3.0 mm. Symmetrical crack patterns occurred for both positive and negative loading directions. Load carrying capacity, Crack patterns, load displacement hysteresis loops, and stress distribution results for theoretically studied specimens were simulated accurately using ANSYS package. It was concluded that Strengthening of specimens by Ferro-cement reduced the effect of axial loading level and longitudinal steel ratio in the beam on the ultimate load of studied specimens. Changing the orientation angle of expanded wire mesh from 60° per Ferro-cement layer to 45° had a minor effect on the ultimate load but a significant effect on the ductility of studied specimens.
shear use variety of test configurations, a review of selected experimental setups is presented. Isolated specimens subjected to gravity loading at the center of the slab were tested among others by Elstner and Hognestad (1956), Kinnunnen and Nylander (1960) and Moe (1961). Elstner and Hognestad (1956), Hanson and Hanson (1968) and Corley and Hawkins (1968) tested specimens with distributed uniform load. Most of the slabs, tested under gravity load, were supported at the edges (Elstner and Hognestad (1956), Moe (1961), Sieble et al. (1980), Swamy and Alo (1982), Harajli et al. (1995), Adetifa and Polak (2005), Naaman et al. (2007)). However, Broms (2007) and Brikle and Dilger (2008) tested specimens supported at discrete points and not around the edges in order to simulate the points of contra-flexure. Specimens subjected to gravity load and unbalanced moments were tested by Hawkins et al. (1974), Robertson et al. (2002), Pan and Moehle (1989), Elgabry and Ghali (1987) and El-Salakawy and Polak (1999). Pan and Moehle (1989) tested slab-column connections subjected to lateral displacement cycles and gravity load. They found that the lateral drift capacity of the connections is dependent on the gravity to shear ratio. An increase in the gravity shear ratio with the lateral cyclic loading led to a reduction of strength, stiffness and displacement. It was recommended that the 0.4 gravity to shear ratio as the upper limit in order to have a drift capacity in the range of 1.5%. Many important contributions regarding the lateral cyclic loading applied to the slab-column connections have been offered also by Robertson and Durrani (1992), Megally and Ghali (2000) and Bu and Polak (2009).
John et al., 2001 presented a study on evaluation of flexural live-load distribution factors for a series of three-span pre-stressed concrete girder bridges. The response of one bridge, measured during a static live load test was used to evaluate the reliability of a finiteelement model. The finiteelement models were also used to investigate the effects that lifts, intermediate diaphragms, end diaphragms, continuity, skew angle and load type have on distribution factors. Live load distribution factors were calculated by modelling five possible cases of bridges and from there live load distribution factors are calculated and compared with recommendation of codes for live load distribution factors. Moments on girders were calculated by taking differences in reading of strain gauge embedded in the girders. The girder element was modelled as shell element. From the analysis it can be observed that distribution factor calculated by finiteelement method was 6% higher than that of calculated by LRFD specifications. Distribution factors decreased with increasing skew. If the distribution factors calculated with the finiteelementanalysis had been used in the design of the bridge, the number of stands and the release strength could have been reduced and the span could have been increased. Rabee et al., 2015 presented a study on establishing a numerical analysis model which is based on finiteelement code to investigate structural behaviour of keyed joint under direct shear. The concrete damage plasticity model along with the pseudo damping scheme were incorporated to analyze the system for micro cracks and to stabilize the solution. The established numerical model was then used for parametric study on factors affecting shear behaviour of keyed dry joints, in the case of confining pressure. For the analysis ABAQUS software was used for modelling and analysing and experimentalanalysis was also done for comparison purpose. Initial stiffness, vertical displacement at the peak load and ultimate shear strength of a dried keyed joint increased as the confining pressured increased. Crack propagation obtained from numerical simulation accords very well with that from experimental study for the entire specimen. The maximum deviation in the prediction of ultimate shear strength was found to be 9%. Ultimate failure of the dry keyed joints was fracture of concrete along the root of the key with shearing off. The initial stiffness, vertical displacement at the peak load and ultimate shear strength of a keyed dry joint increased as the confining pressure increased.
Experimental behaviour of beam-columnjoints in building frames strengthened by ferrocement under cyclic loading, previously tested , was numerically predicted in this research using the ﬁ nite element package ANSYS 10.0 . The description of the tested specimens, which are predicted in this research, is shown in Table 1 and the test setup for a typical specimen is shown in Fig. 2(a). The retroﬁtted specimens were wrapped by a layer or more of wire mesh (with overlap of 100 mm) and each mesh layer was ﬁxed to the embedded shear connectors. The strengthened specimens were plastered with a thin layer of rich cement mortar. Fer- rocement layers were considered in the analysis fully bonded to the concrete elements. Boundary conditions, positions of the applied loads and the measurement set-up are described in the recent paper published by the ﬁrst author . Typical idealization of test beam-to-column joint is shown in Fig. 2(b). The specimens were analyzed under quasi-static displacement control technique. The lateral loading procedure used for all tests is shown in Fig. 3 and it is a load displacement to simulate the one applied to the experimental work . The imposed displacement was applied at the tip of the beam and it is related to the yield of the joint in order to simulate the experimental tests . A correlative study, based on the ultimate capacities and envelope of load displacement hysteresis, was conducted to verify the numerical model with the experimental results. It is worth mentioning that positive and negative envelopes were almost similar and therefore positive envelopes were only considered in the comparison.
The finiteelement meshed for both columns and walls are shown in Fig. 4, in which square meshing method is selected to use. Fixed boundary conditions are applied to the bottom of the components and axial forces are applied to the top surface of the wall. By setting lateral force at the center of the top beam, the model can obtain the propertied of the composite shear walls.
Experimental behaviour of beam-columnjoints in building frames strengthened by ferrocement under cyclic loading, previously tested , was numerically predicted in this research using the finiteelement package ANSYS 10.0 . The description of the tested specimens, which are predicted in this research, is shown in Table 1 and the test setup for a typical specimen is shown in Fig. 2(a). The retrofitted specimens were wrapped by a layer or more of wire mesh (with overlap of 100 mm) and each mesh layer was fixed to the embedded shear connectors. The strengthened specimens were plastered with a thin layer of rich cement mortar. Ferrocement layers were considered in the analysis fully bonded to the concrete elements. Boundary conditions, positions of the applied loads and the measurement set-up are described in the recent paper published by the first author . Typical idealization of test beam-to-column joint is shown in Fig. 2(b). The specimens were analyzed under quasi-static displacement control technique. The lateral loading procedure used for all tests is shown in Fig. 3 and it is a load displacement to simulate the one applied to the experimental work . The imposed displacement was applied at the tip of the beam and it is related to the yield of the joint in order to simulate the experimental tests . A correlative study, based on the ultimate capacities and envelope of load displacement hysteresis, was conducted to verify the
accurate three dimensional finiteelement Model (FE) capable of predicting the actual behaviour of beam-to-columnjoints in cold form perforated steel frame subjected to static loads. The software package ANSYS is used to model the joint. The beam- column type connection is used for study. This is chosen for its complexity in the analysis and their inheritable non-linear behaviour. The experimental test in the literature for normal section was chosen to verify the finiteelement model. The results of normal section of model in literature were compared with normal section of analytical model. Then the normal section of analytical model compared with perforated section of analytical model, to check the compatibility of the perforated section. The structural behaviour of the connection including the moment – rotation relation, Load -deflection curve, the yield strength, and ultimate moment capacity of the connections were studied. The main parameters considered in this study were the thickness of section for the constant span and number of bolts and its arrangement for the connection.
ABAQUS is a finite-elementanalysis software. Abacus provides a pre-processing and post processing environment for the analysis of models. It is used in a wide range of industries like automotive, aerospace etc., and also is extensively used in academic and research institutions due to its capability to address non-linear problems. The FiniteElement Method (FEM) is a numerical analysis for obtaining approximate solutions to a wide variety of engineering problems. This has developed simultaneously with the increasing use of high-speed electronic digital computers and with the growing emphasis on numerical methods for engineering analysis.
Beam-columnjoints are an important part of reinforced concrete (RC) moment resisting frames in earthquake- prone areas. The cross sections of beams and columns that are close to the joints in RC structures are critical, and under the impacts of strong earthquake waves, they are exposed to large bending moments and shear forces. The moment resistance frame in the beam-column joint controls the transmission of force to the structure. In RC frames designed for gravity loads, the design check for joints is not normal. In recent seismic attacks, the joints collapsed due to shear failure. The moment resistance frame should be sufficient in terms of the overall sizes at the preliminary design, and the joint should be provided with necessary reinforcement. For structures in low and medium seismic zones, the seismic effect should be considered. Reinforcement of the structure as per the gen- eral code of practice may not meet the present seismic codal provision. A beam-column joint is structurally less efficient when subjected to large lateral loads, which include strong winds, earthquakes and explosions. For structures in these areas, high percentages of traverse hoops in the joint core are required to achieve high strength, stiffness and ductility under cyclic loading.  conducted experimental and analytical studies using ANSYS, and additional cross bracing reinforcement improved the seismic performance.  used continuous SIMCON jackets to increase the confinement of column lap splice in the joint region.  carried out nonlinear dynamic analysis by hysteretic response of the exterior beam-column joint with stiffness degradation without the punch effect and with low and high punch effects.  conducted two groups of different joint designs of rein- forcement details: joints reinforced with traditional steel rebar and another group of prefabricated cage system (PCS). Their study concluded that the PCS reinforced joints had slightly higher strength
459 Abstract—Many of the existing reinforced concrete structures throughout the world are in urgent need of strengthening, repair or reconstruction because of deterioration due to various factors like corrosion, lack of detailing, failure of bonding between beam-columnjoints, increase in service loads, etc., leading to cracking, spalling, loss of strength, deflection, etc., Direct observation of these damaged structures has shown that damage occurs usually at the beam-columnjoints, with failure in bending or shear, depending on geometry and reinforcement distribution type. .A nonlinearfiniteelementanalysis that is a simulation technique is used in this work to evaluate the effectiveness of retrofitting technique called “wrapping technique” for using carbon fibres (FRP) for strengthening of RC beam-column connections damaged due to various reasons. After carrying out a nonlinearfiniteelementanalysis of a reinforced concrete frame (Controlled Specimen) and reinforced concrete frame where carbon fibres are attached to the beamcolumn joint portion in different patterns ,the measured response histories of the original and strengthened specimens are then subsequently compared. It is seen that the strengthened specimens exhibit significant increase in strength, stiffness, and stability as compared to controlled specimens. It appears that the proposed simulation technique will have a significant impact in engineering practice in the near future.
Steel fiber reinforced concrete (SFRC) is widely used in reinforced concrete construction due to its high toughness, tensile and flexural strength. It has also been observed from recent experimental work that the use of carbon nano-fiber (CNF) in reinforced concrete members enhances the mechanical behaviour of material by reducing the size and propagation of cracks. The main focus of this study is to investigate the effect of steel fibers (SF) and carbon nano fibers (CNF) on the performance of steel- concrete-steel (SC) doubleskin composite members under seismic loading. A force based fiber beam- columnfiniteelement is adopted to simulate the inelastic flexural and shear behaviour of SC composite members. Shear deformation is modelled using a Timoshenko beam type approach along the element. The fiber reinforced concrete constitutive model follows the softened membrane model (SMM) which accounts for compressive stress and strain softening, tension stiffening and cyclic damage. The hysteretic steel material constitutive law follows the well-known Menegotto–Pinto model which includes isotropic strain hardening and Bauschinger effect. The interaction between concrete and steel is considered. The model is validated with experimental test data available in the literature for fiber reinforced members. The enhanced effect of fibers on the global and local bevajor of SC members is investigated.
The details of testing columns were shown in Fig.1. Analysis was carried out in 12-column specimens, where all columns had a square cross-section with a 300mm side and length of 3200mm. Analyzed columns had main reinforcement(Steel, GFRP) 6#12mm, 6#16mm,6#20mm 8#12mm,8#16mm and 8#20mm.
In order to clear constructional design of corner joint, it is necessary to further inves- tigate mechanical property of corner joint in gabled frames. Through static test and finiteelement software analysis of comparing the panel zone with and without in- clined stiffener. Some conclusions are given in the article. The load displacement curves show that the capacity of oblique nodes installed within stiffening rib compo- nents is enhanced i.e. 40% more than those without stiffening rib nodes. The results reveal that in the gabled frames, the corner node with the inclined stiffening rib can improve the bearing capacity of the specimens. When the extraterritorial flange is tension, the erection of the inclined stiffening rib can prevent structural failure and improve effectually the ductility of the structure.
Abstrac t: Automobile systems today is going through major changes and as concert to comfort the suspension system and its working is very impo rtant. The study of suspension system and dynamic analysis are discussed in this paper. The links of the suspension are assumed to be fle xible and the elastic stiffness, mass, and geometric stiffness matrices are obtained by using Finite Ele ment Method . In order to e xpress the linear equation of mot ion, suspension link forces required for the geometric stiffness matrices are assumed as constant. Also, the oscillations of the suspension links are neglected since the base displacement is chosen in sma ll a mp litude. The FEA done by divid ing the lo wer and the upper arms into two e le ments . Double wishbone suspension of a quarter cars is modelled assuming the suspension links to be rig id.
In this paper, the effect of the actuator placement on controlling the vibration of the beam and plate will be tested using numerical simulations and Experimental. The location of the sensor will be fixed throughout the simulations, where the actuator will be placed at different locations. In this paper, LQR controller will be used to study the effect of the actuator placement. We will implement the LQR controller on a piezoelectric laminate beam. The controller will be implemented such that the vibration for the closed- loop system is minimized.
Using FEA along with thin adhesive layer analysis (TALA), Fongsamootr et al.  carried out a paramet- ric study of combined adhesive-riveted lap joints. The FEA/TALA results were used to predict the fatigue life of the joints as functions of the three parameters. The results showed that the maximum tensile stress is smaller with a smaller panel thickness. The results also showed that the stress concentration factor in the joints was reduced when the stiffness of the adhesive layer was increased or when the thickness of the adhesive layer was decreased. In Kunc et al.’s work , three joining methods were evaluated including riveting, adhesive bonding, and combination of riveting and adhesive bonding. FEA was used to predict the behavior of the structure up to the point of damage in the composite. A general method was devised by Dechwayukul et al.  for determining the effects of thin layers of sealants or adhesives on the mechanical behavior of riveted lap joints using FEA. The analyses revealed that adhesive layers introduce large increases in the in- and out-of-plane displacements, reduce bending and stress concentration factors (SCF), and increase the fatigue life of riveted lap joints. A 3D FE model of the riveting process was simulated by Atre and Johnson  to determine the effects of interference and sealant on the