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shows the comparison of the results of the different tension softening constitutive models under mediummeshing and the results of the test.
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In this paper, some simple stress-strain relationships of the concrete material recommended in relevant Codes are appropriately simplified, then the damage factors of the simplified plastic damage constitutive model is determined based on Sidiroff’s energy equivalence principle. Mechanical characteristics of the concrete material under the simple t...
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Citations
... The performance of recycled concrete was simulated using the concrete damage plasticity model (CDPM) provided in ABAQUS [20], and the compressive principal relationships are expressed as follows [21] : The uniaxial tensile behavior of concrete was defined by inputting fracture energy [22]. Fracture energy Gf = α(0.1fc ...
This paper aims to investigate the cyclic performance of the connections between the recycled aggregate concrete (RAC) column and steel H-beam. In this connection system, the steel beam is welded to the end plate to form an integral unit, which is bolted to the column. The differences in seismic performance between the novel casing-type one-side bolted end-plate connection and the conventional all-welded joint with external diaphragm and top-seat angle connection were investigated. Three types of joints with different connection details were designed and fabricated at a reduced scale of 1:2, following the principle of strong columns and weak beams. The low cyclic lateral loading test was performed by beam-end loading to observe the loading process and failure morphology of the joint model. The load-beam end displacement hysteresis curve and the skeleton curve were obtained to analyze the joint load eigenvalues, ductility, energy dissipation, and stiffness degradation. The experimental results showed that all three specimens exhibited beam-end failure and demonstrated good ductility. Furthermore, a finite element model was established. The effects of axial compression ratio, steel tube width-to-thickness ratio, outer tube, and end-plate thickness on the bearing performance of the outer tube one-side bolted end-plate joint under lateral loading were analyzed. It was found that the bearing capacity and stiffness of the specimens increased with increasing steel tube width-to-thickness ratio, outer tube thickness, and end-plate thickness. Changes in the axial compression ratio had little effect on the bearing capacity and stiffness of the specimens.
... Since it is a ceramic material, the behavior of concrete is quasi-brittle, so models that better represent the damage are considered acceptable in simulations of this material (Demin and Fukang, 2017). A multiaxial model called Concrete Damaged Plasticity (CDP), proposed by Lubliner et al. (1989) and further developed by Lee and Fenves (1998). ...
... The experimental critical crack was also seen in the numerical results, as shown in figure 8c, accompanied by some flexural cracks. Similar results were observed in other studies (Al-Osta et al, 2017;Demin and Fukang, 2017;Jumaa and Yousif, 2019;Arcine, Menon, and Krahl, 2023). Experimentally, beam failure occurred when the resistance capacity of the transverse reinforcement was exhausted. ...
O objetivo desta pesquisa é investigar numericamente o reforço e a interface adesiva de uma viga em concreto armado a esforços cortantes. O estudo foi baseado em resultados experimentais coletados da literatura atual. O sistema de reforço consistiu em usar mantas de Polímeros Reforçados com Fibras de Carbono (PRFC) coladas em “U” em regiões críticas de cisalhamento. Os resultados da simulação numérica foram considerados eficientes. Pequenas diferenças na ductilidade entre as vigas simuladas e as experimentais foram observadas, fato devido a não consideração do escorregamento das barras da armadura. Mesmo com reforço, colapsos frágeis ainda são observados, provenientes do descolamento de parte do PRFC.
... The concrete used in the design is C40 grade concrete, which has allowable compressive strength "f ck " =26.8 N/mm 2 and allowable tensile strength "f tk " =2.39 N/mm 2 , the density = 2400 kg/m 3 , for the elastic stage; Elastic modulus "E" equals 30E9 Pa, and Poisson's ratio "" =0.2, for the plastic stage; Dilation angle "" =30 0 , Eccentricity "e" =0.1, Ratio of initial equi-biaxial compressive yield stress to initial uniaxial compressive yield stress is "f b0 /f c0 " = 1.16, ratio of the second stress invariant on the tensile meridian to that on the compressive meridian "K c " = 0.6667, and viscosity parameter "" = 0.000. The input parameters for compressive and tensile behavior parameters are listed in Table 3 and Table 4, respectively [19]. The same type of finite elements is used for the concrete parts as for soil parts. ...
... This study adopted the concrete damaged plasticity (CDP) model, which applies to brittle materials, such as concrete. Based on concrete isotropy, concrete's tensile cracking and compressive fracture were simulated [29]. The damage, in this case, was a progressive weakening in the internal cohesion of the material under loading, which produced defects, cracks, and micropores in the loaded material [30]. ...
Steel formworks are widely used in prefabricated buildings thanks to their good characteristics. With the rapid development of engineering construction in China, steel formwork concrete structures, characterized by convenient construction, good seismic performance, and high strength, are expected to be more extensively applied in engineering practice. However, the bearing capacity of different forms of steel formwork concrete is still unclear. Two prefabricated columns with different internal diaphragm styles were set up for axial compression tests to investigate the performance of steel formwork columns. This study conducts monotonic static loading tests on six prefabricated steel tube column specimens and performs finite element analysis by taking steel tube thickness, rebar diameter, and internal diaphragm style as the influencing parameters. The results show that the prefabricated specimens can work in the test process, and the ultimate bearing capacity is consistent between the tests and numerical simulation. Moreover, the nephograms obtained from numerical simulation also conformed to the failure mode of the specimens in the test process. Therefore, the finite element model proposed in this study can accurately predict the stress performance of steel formwork concrete stub columns. These results offer guidance for future engineering practices.
... Due to the complexity of concrete materials, there is no universal constitutive model for concrete (Demin, W. et al., 2017), so the CDP model used in the finite element calculation is the CDP model obtained by experiment. To obtain the CDP model for concrete,100 mm × 100 mm×100 mm concrete specimens were cast for uniaxial compression and Brazilian tension tests in accordance with the specification GB/T50081 (2002). ...
To predict the impact resistance of steel fiber reinforced concrete (SFRC), 50 specimens with different fiber lengths and different fiber contents were loaded using ABAQUS finite element software to obtain data in this paper. Two machine learning (ML) models, backward propagation-artificial neural network (BP-ANN) and support vector machine (SVM), were used to train the data. The results show that in the prediction of the impact resistance of steel fiber reinforced concrete by this model, the deviation of the predicted values from the real values is small, and the two models are well fitted. To further optimize the model, the parameters of the prediction model were adjusted using the whale optimization algorithm (WOA) in this paper, and the accuracy of the optimized model was significantly improved. After optimization, the WOA-BP-ANN and WOA-SVM models have better generalization ability and higher prediction accuracy than the WOA-SVM model.
... Apart from that, damage was assumed to occur in PCC under compression (d c ) and tension (d t ). The damage evolution was estimated through the Sidiroff's energy equivalent principle, described in Eq. (21) [56]. The damage of PCC in tension was limited to 0.99 to avoid convergence problems [31]. ...
... This assumption was made because of the pseudoductile behaviour presented by concrete reinforced with fibres under tension. The damage evolution of FRRAC and FGC in compression was also estimated through Eq. (21) [56]. ...
Recent studies applied the concept of functionally graded material in fibre reinforced recycled aggregate concrete (FRRAC) to produce functionally graded concretes (FGC) with enhanced post-cracking flexural behaviour. In these studies, two-layered FGC were produced using plain cement concrete (PCC) and FRRAC in the top and bottom layers, respectively. It was found that a top layer of PCC as thin as 10% of the total height of the specimen (or h/H = 0.90) can enhance the post-cracking flexural behaviour of FGC. Based on these experimental results, this study aims to demonstrate the feasibility of using FGC in construction projects by estimating the ratio h/H that results in an optimal post-cracking flexural response of FGC beams produced with PCC and FRRAC. For this, the finite element analysis software ABAQUS, and the analytical model based on an analysis of evolutionary sections were used to estimate the flexural behaviour of homogeneous FRRAC and FGC beams considering different values of h/H. Then, the simulated results were compared with previous experimental results and the optimal h/H of FGC with FRRAC was evaluated considering its application in rigid pavements. In general, the simulated results indicate that the optimal post-cracking flexural performance is obtained for h/H between 0.80 and 0.90. Furthermore, the lowest slab thickness was achieved for h/H = 0.80.
... Concrete model. A state-of-the-art concrete model was utilized and implemented in ANSYS Mechanical software; namely, the microplane coupled damage-plasticity (widely described in many papers: before the year 2000 [5-9], after the year 2000 [10][11][12][13][14][15][16][17] and the last five years [18][19][20][21][22][23][24]) with enhanced gradient regularization. The regularization uses 2 additional degrees of freedom per node, though it reduces solution sensitivity to finite element mesh size. ...
The paper presents numerical analysis methods of High-Strength Concrete (HSC) beams prestressed with unbonded tendons. Furthermore, it compares obtained results with experimental data from the literature. Prestressing tendons have been modelled in a discrete form, using one-dimensional finite elements. A temperature drop inflicted prestress force. Contact issues have been considered, i.e. friction and pressure at the interface between the cable and the duct wall. In the work, it was found that it is possible to obtain satisfactory accuracy of results with the model in use. Accurate P-Δ (load-deflection) curves were achieved matching experimental data.
... e concrete compressive hardening and tensile stiffening data have been considered in terms of crushing and cracking strain, respectively. e crushing, cracking, and plastic strain (for both compressive and tensile) of concrete has been determined using (10)- (15), as provided in [15][16][17][18][19][20]. Figures 3(a)-3(d) show the compressive stress-crushing strain, compressive damagecrushing strain, tensile stress-cracking strain, and tensile damage-cracking strain curve of concrete, respectively, under different concrete grades to model the specimens. ...
... Ductile structures have the capability of dissipating hysterically large magnitude of energy during the inelastic cyclic deformations. A displacement ductility factor is computed as the ratio of the displacement at ultimate to the displacement at yield according to equation (17). In this study, the ductility of RC shear wall-slab slab connection calculation based on simplification method presented in Figure 15. ...
Finite element modeling is becoming widely applicable for the assessment of structural behavior, which is accurate and reliable, since conducting the full experimental test is time-consuming and very expensive. Previously conducted research confirmed that there is a good agreement with the experimental tests. In this study, a nonlinear finite element analysis with the ABAQUS software package has been taken to investigate the response of reinforced concrete exterior shear wall-slab connection subjected to cyclic loading. The structural responses such as load-carrying capacity, energy dissipation, ductility, and stiffness degradation have been studied. Connection type, an aspect ratio of the thickness of the slab to the thickness of the shear wall ( t s / t w ), the aspect ratio of the height of the shear wall to the effective width of the slab (H/We), and concrete strength were used as study parameters to evaluate their effect on the structural response of the connection. A total of sixteen models have been selected based on the parametric study and objective of the study. The results show that the exterior shear wall-slab connection with U-type connection has high load-carrying capacity than the other connection types. As the aspect ratios of t s / t w , H / W e and concrete strength increase, the ultimate load capacity and energy dissipation capacity increase. In other words, as the number of loading cycles increases, the stiffness of the connection is decreased.
... The identification of constitutive models is a fundamental phase to replicate experimental tests where stress-strain curves populated from these experiments are typically used to define its mechanistic behavior. The essential elements for any plasticity model are yield criteria, flow rule, hardening rule and damage evolutions (both hardening and softening may be accounted for) [29,[54][55][56][57][58][59]. The yield criteria often used the Mohr-Coulomb and Drucker-Prager criteria F r ð Þ ¼ c where c is the cohesion in which represent the evolution law that can be determined by plasticdamage variable (d) range between 0 and 1, and F r ð Þ is the first degree of the stress component [4,5]. ...
This paper discusses the identification and characterization of material parameters of a concrete damage plasticity constitutive model that is used to describe the mechanical responses of mortar, bricks, and concrete, defined here as the three material components of an unreinforced masonry infill wall system. Each of these material components exhibits a nonlinear and inelastic response, which it is hypothesized can be fully described by the use of a single concrete damage plasticity material model. A comprehensive investigation of experimental tests on these materials found in the literature showed large variations in their stress–strain mechanical responses when subjected to uniaxial compression loading. This may be attributed to different factors, including material properties, manufacturing, and geometry of the testing specimens. This work focuses on the study of material properties of mortar, bricks, and concrete, with the objective of retrieving optimal model parameters using a quasi-brittle constitutive model. For this purpose, a set of numerical experiments are designed and implemented reproducing standard uniaxial compression tests on each material. The methodology to explore the use of the proposed constitutive model includes a parametric analysis, followed by the deterministic calibration of the model parameters based on a standard optimization approach.
... Isotropic damaged elasticity in tension and compression was employed to present the inelastic behavior of concrete. Describing the stress softening function of the cracking concrete primarily based on the connection among the following failure strain and the cracking stress via the normative uniaxial constitutive relation presented in [18]. ...
The composite construction strategies realize an increasing number of sizeable applications in regions like bridges, ramps, homes, and different exceptional places. The component of composite structure considered in the study contains composite slab, profiled steel sheeting, steel beam, shear connector, and reinforcement cages. The investigation mainly focused on the structural performance of demountable shear connectors in composite slabs and steel beams with profiled steel sheeting. An extensive nonlinear finite element model was used to carry out in FE software Abaqus 6.14. Nonlinear behavior of concrete, stud connector, profiled steel sheeting, reinforcement cage, and steel beam are included in the finite element model. In this study, 24 specimens were taken into consideration to investigate the capacity of the shear connection, the load-slip curve of stud, failures modes of demountable shear connectors, and concrete crushing in the composite floor with profiled steel sheeting. The analysis confirmed that as the diameter of the shear connector increased from 19 to 22 mm, the capacity of the shear connector also increased by 54.313% and 28.903% in both open through and reentrant profiled steel sheeting, respectively. In addition, as the height of the profiled steel sheeting increased from 50 to 64 mm, the capacity of the shear connector is increased by 11.601% and 32.564% in open through and reentrant profiled steel sheeting, respectively. Similarly, when the concrete grade increased from C-40 to C-60, the capacity of the shear connector also increased by 70.128% and 48.301% with open and reentrant profiled steel sheeting, respectively. Furthermore, sensitivity analysis is done to see how much each input parameters affect the output parameter.
