Shear Criteria Research Articles

Comparative Study of Response of Staad.Pro Model with and Without Modeling Plate Element Considering Plan Irregularity: A Review

Abstract: Nowadays, modelling is done on a lot of software in the world, and in India, some of the software is used among all other software. In this research, we have compared the outcome of the different software including STAAD.Pro and ETABS analysis. Many researchers have made efforts to get the best possible results. But our motive is to model plate elements by considering regular and irregular structures to achieve the best possible results. We are going to compare the structure based on maximum storey Displacement, Axial Forces, overturning moments and shear criteria.

Integrity of Melamine Formaldehyde Bonds in Ponderosa Pine Cross-Laminated Timber: Isolating Adhesive Compatibility Effect

Abstract The integrity of melamine formaldehyde bonds in prototype cross-laminated timber (CLT) specimens was tested as part of a project on utilization of ponderosa pine (Pinus ponderosa) from forest restoration programs in the western United States. Bond integrity tests, block shear, and cyclic delamination are prescribed by ANSI/APA PRG-320 (ANSI/APA 2019) and ANSI 405 (ANSI 2018) to qualify new products. Of these, the cyclic delamination criterion is particularly challenging for layups developed in research labs and pilot plants. Delamination is often blamed on poor compatibility between adhesive and wood species, clamping pressure, or distribution of adhesive, neglecting other potential factors. One of the study objectives was to separate the effect of adhesive compatibility from other potential factors affecting bond integrity in CLT. Bonding integrity tests were conducted on prototype specimens bonded with melamine formaldehyde adhesive. Three types of specimens were studied: (1) specimens harvested from panels fabricated in an industrial CLT plant, (2) specimens harvested from panels fabricated in a pilot-line, and (3) short blocks cross-laminated from 102 by 102-mm sections. The short blocks included sections with juvenile wood and blue stain on bonded surfaces. All samples passed the PRG-320 block shear criteria. All short blocks passed the delamination criterion, demonstrating sufficient adhesive compatibility with the surfaces regardless of heavy presence of blue stain and juvenile wood. Specimens harvested from panels did not meet the delamination criterion. Delaminations developed near preexisting interlaminar gaps observed in prototype panels, which may be related to thickness variation or to inconsistent clamping pressure.

MODELLING AND INTEGRATING OF EXPERIMENTAL ANALYSIS FOR PREDICTING THE PARAMETERS OF KENAF FIBRE-REINFORCED CONCRETE BEAM-COLUMN JOINT

To lessen the environmental impact of infrastructure projects, the construction sector has recently demonstrated a growing interest in sustainable materials. Kenaf fibre-reinforced concrete (KFRC), which has improved mechanical qualities and biodegradability, has emerged as a possible eco-friendly substitute. The intricate interactions between material composition, geometrical factors, and load-bearing capacities make it difficult to optimise the design of structural parameters of KFRC beam-column joints. The beam-column joints used in this study were designed based on ACI 318-19 shear criteria. This study suggests a novel method for precisely predicting the parameters of kenaf fibre-reinforced concrete beam-column (KFRC-BC) joints by combining machine learning modelling and experimental investigation. Experimental data are carefully documented to establish the reality, including load-displacement responses and beam-column joint parameters such as shear, stiffness, ductility, crack load, energy absorption, and ultimate load. These data were used in the modelling through GeneXproTools 5.0 (GEP) and an empirical relationship with mathematical expressions has been proposed for each joint parameter. R2 statistical analysis is used to evaluate the model’s efficacy. In addition, it has been demonstrated by varying intensity and correlation that deep learning may be used to determine the precise concrete structure parameters in civil engineering without the need for experimental research. The shear spacing could be increased by 25% to 50%. Concrete strength influences all these characteristics.

Structural Performance of Prefabricated Composite Girders for Railway Bridges along with Girder-to-Deck Interface Connections for Mechanical Injection

Recently, to resolve a growing need for durable and resilient railway bridge construction/reconstruction systems, a great amount of research has been carried out in many countries. As a part of such studies, prefabricated composite girders with an innovative girder-to-deck connection have been proposed that facilitate construction by eliminating interference during on-site processes. In this study, a railway bridge prototype of prefabricated composite girders with girder-to-deck connections was designed to facilitate future application enhancement of off-site construction. Then, prefabricated composite girders were developed by deploying different girder-to-deck connections through geometric detailing of reinforcement, headed stud connectors, and precast decks. Based on the calculation theory of interface shear transfer, the detailed design of different girder-to-deck connections was carried out, in particular the reinforcement spacing. Furthermore, finite element analysis of prefabricated composite girders was conducted to determine the flexural moment strength of prefabricated composite girders. Parametric studies were carried out to consider the factors affecting the detailed design of the connection, ensuring that the connection is correctly designed, thereby ensuring the structural performance of prefabricated composite girders. From the results, conclusions were drawn. The developed cases satisfied the interface shear criteria according to both conventional and plastic approaches. There was no significant difference in flexural moment strength between the developed cases since all cases were designed with the full shear connection. In all cases, the flexural performance was ensured and can be used for railway bridges. The most optimum case of prefabricated composite girders is selected in specific design situations.

Integration of rock joint roughness into the Mohr-Coulomb shear behaviour model – application to dam safety analysis

Based on a previous experimental study that we conducted on granite joint replicas including thirty direct shear tests, this article proposes to integrate the joint roughness in the Mohr-Coulomb shear behaviour model (MC). The model integrates joint roughness into constitutive stress-displacement relationships describing mechanical behaviour of rock joint. The shear strength of rock joint is assessed by the MC shear criterion that takes into account the apparent cohesion. This MC model integrating rock joint roughness component is validated against other experimental results from the literature. It is able to accurately predict the peak shear strength of an unbounded rock joint with an average relative error of 7.9%. It is finally used to assess the role of joint roughness on the shear behaviour of a gravity dam foundation.

Thermo-mechanical response of 3D braided composites with different braiding angles under high strain rate punch shear loading

Thermodynamic responses of three-dimensional (3D) braided composites with different braiding angles (25°/35°/45°) under high strain rate punch shear loading were studied through experiments and simulations. Plasticity criterion, shear criterion and interface damage criterion are introduced into the developed full-scale thermal-mechanical coupled finite element analysis model. Combined with macroscopic experiments and microscopic analysis, effects of braiding angle, strain rate and thermal-mechanical coupling on 3D braided composites were discussed from stress propagation and adiabatic temperature rise process. Peak stress and energy absorption increased with braiding angle or strain rate, which increased punch shear resistance of braided composites. Finally, complex thermal-mechanical coupling damage mechanism of composites was revealed through distribution of stress and temperature. Composites eventually appeared three main damage modes: interface debonding, fiber fracture and fiber extraction. Damage and energy absorption in critical loading region were also obtained. A low temperature and low stress area formed in the middle of shear band of composites. Plastic strain and thermal strain aggravated fracture of fibers.

Sustainability of Heavily Loaded Raft Foundations on Granular Soils of Arabian Peninsula with Soft Clay Layer

Sandy soil formations are widespread around the globe, particularly in the Arabian Peninsula. The Sandy formations were created as a result of long-term geological activities including but not limited to alluvial and wind deposition. Since the alluvial deposits contain fine soils, the clay layers are often intercepted in the foundation supporting strata. The geotechnical foundation design based on field and lab investigations usually relies on the average response of the layered strata and can satisfy both shear and settlement criteria. However, the enduring sustainability of the heavily loaded foundations is required to be investigated in detail. In this study FEM based numerical investigations have been carried out on a thin raft foundation resting on granular soil, with a soft clay layer in the influence zone. The COMSOL Multi-physics platform has been used for the analysis. The study cases are planned based on the thickness of the clay layer and building load. The analysis results predict the risk involved in the sustainability of rafts in terms of the settlement. The field engineers and designers are recommended to consider the risk and plan accordingly

Dynamic Response of a Hypersonic Rocket Sled Considering Friction and Wear

The dynamic response of a hypersonic rocket sled was studied by considering the time-varying friction coefficient and the gap caused by wear between the slipper and track. A multibody dynamic model for a hypersonic rocket sled system was established by considering the time-varying mass and moment of inertia, nonlinear aerodynamic loads, engine thrust, track irregularity, and nonlinear contact force. As for the wear calculation, the ductile and shear criteria were used as the material damage criteria, and slipper wear was determined by the number of damaged elements. A rocket sled test was also carried out, and the dynamic response of the sled was measured. The results showed that the computational sliding displacement and velocity of the third-stage sled matched well with the test values. The computational root mean square (RMS) values of the vertical acceleration of the third-stage sled front slipper considering friction and wear matched better with the test values than with the case without considering friction and wear, which underestimated the RMS value by approximately 20.1% at Mach 5. The importance of considering friction and wear and the correctness of the computational method were validated. It is also found that the kinetic friction coefficient decreased with an increase in the product of the pressure and velocity. The wear height of the slipper increased almost linearly with the sliding displacement. The test results showed that the vertical acceleration power spectral density of the third-stage sled front slipper increased with time in the full frequency band below 2000 Hz. This study will guide the design and optimization of hypersonic rocket sleds.

Shear Criterion and Experimental Verification for Antivibration Fatigue Design

Shear Criterion and Experimental Verification for Antivibration Fatigue Design

What comes first: The fault or the ductile shear zone?

Crustal scale fault zones extend below the brittle-ductile transition as ductile shear zones. Here we address the question of which regime, brittle or ductile, initiates and controls the overall system of shear localization. Observations of crustal scale but low displacement conjugate strike-slip faults show that they are typically nearly orthogonal, as expected from plastic shear criteria. Sub-crustal scale conjugate strike-slip faults, however, have acute dihedral angles in accordance with the Coulomb fracture criterion as Anderson's theory predicts. We modeled the crustal scale system with strain weakening rheologies that follow the Coulomb and von Mises criteria respectively, within the brittle and ductile regimes. We find that when the strain weakening rate in the ductile regime exceeds a critical value the entire system shears in the von Mises mode with orthogonal conjugate shears forming at all depths, in accordance with the observations. There is, as observed, no deflection of fault orientation at the brittle-ductile transition. Anderson's theory of faulting thus breaks down for crustal scale faults. This difference in behavior was already evident in data presented in Anderson's 1951 book, but its significance was not understood at that time.

Psuedo static stability analysis of rock slope using patton\u2019s shear criterion

A deterministic model for the factor of safety of an idealized rock mass for planar mode of failure is developed adopting Limit Equilibrium Method (LEM) using Patton’s shear strength criterion and considering practically occurring conditions such as the effect of tension crack, water filled up in tension crack, horizontal and vertical seismic acceleration, rock bolt stabilizing force and surcharge. In the Pseudo-static analysis horizontal seismic acceleration is taken outward from the slope and vertical seismic acceleration is considered in both the direction i.e. towards the direction of gravity (downward) and opposite to the direction of gravity (upward). An expression of normal stresses as limiting criterion has been derived in order to compare the field normal stresses along the failure surface. A detailed parametric study has been presented to investigate the influence of vertical seismic coefficient for both the direction on the stability of rock slope using developed expression. For high normal stress along the failure plane, it is observed that the factor of safety decreases with increase in the value of vertical seismic coefficient towards the direction of gravity and increases linearly with increase in the value of vertical seismic coefficient against the direction of gravity and the opposite trend has been found for lower normal stress. The vertical seismic coefficient against the direction of gravity has predominant effect on factor of safety of rock slope as the rate of increase/decrease of factor of safety with vertical seismic coefficient is more against the direction of gravity. Hence in determining the critical factor of safety, effect of vertical seismic coefficient against the direction of gravity should be considered.

Determination of a safe drilling mud window and optimal drilling mud pressure by shear and tensile failure criteria

Wellbore drilling is the main activity to access oil reservoirs for oil production. This study aimed at presenting a safe drilling mud window using two criteria for estimating the minimum and maximum drilling mud pressure in order to prevent tensile and shear failure in oil wells. To this end, data on oil wells was first collected. To calculate the lower limit of the mud window, the oil well was modeled at different drilling mud pressures with the help of the finite difference software FLAC2D. By plotting the normalized yield zone area (NYZA) versus the mud pressure, NYZA = 1 was considered as the shear failure threshold, the corresponding pressure to which was considered as the lower limit for the drilling mud weight. To calculate the upper limit of the mud window, the wellbore was modeled with the help of the finite element software, Abaqus. To this end, the drilling mud pressure was gradually increased, and according to the increase in the crack length in the borehole, the pressure causing tensile failure was considered as the upper limit of mud weight. Ultimately, two linear relationships were proposed using the multivariate linear regression analysis in SPSS. In the first relationship, the minimum drilling mud pressure to prevent a shear failure is estimated using pore pressure, minimum and maximum horizontal stresses, cohesion, and internal friction angle. The second relationship estimates the maximum drilling mud pressure to prevent a tensile failure using pore pressure, minimum and maximum horizontal stresses, and maximum and minimum tensile strengths. Combining these two relationships, a new correlation was obtained to estimate the optimal drilling mud pressure. As its main innovative aspect, this study aimed at providing a safe window for drilling mud using two criteria for estimating the minimum and maximum drilling mud pressures in order to prevent shear and tensile failures in oil wells in south Iran oilfields.

Whitmore Section and Block Shear Failure Analysis on a Bolted Gusset Plate using Finite Element Method

In order to determine the tensile capacity of a bolted gusset plate, the Block Shear capacity often came out as the most common failure. However, in the SNI 1729-2015, it’s stated on a User Note in section J4-1 that an element under tension should be checked against the Whitmore Section criterion. The analysis done in this research paper compared these two failure criteria on a few case models of a bolted gusset plate under tensile stress. The Finite Element Method, with the assistance of ABAQUS software, is used to determine the failure of the modeled cases. The results of the analysis will compare all of the gusset plate’s failure criteria of the Whitmore Section, Block Shear and the Finite Element Method. This paper proposes that the Whitmore Section check is deemed unnecessary in light of Block Shear criterion which proven by the FEM as the correct failure of the plate.

Dynamic shear amplification of reinforced concrete coupled walls

Dynamic shear amplification has been commonly studied in cantilever reinforced concrete wall systems, however, coupling beams or slabs can generate axial loads that can modify the response. A parametric study is carried out that covers 432 nonlinear time-history analyses (72 models with 6 records) of 2 coupled walls with different length, including variations in the amount of boundary element steel ratio (1%, 3% and 5%), amount of slab steel ratio (0.0%, 0.3% and 0.6% − 0.0% is defined for connected walls without coupling), building height (25 m, 50 m and 75 m), and wall length (2 m, 4 m and 6 m). The walls are represented with nonlinear fiber models; while the coupling slabs are elastic within the length with a rigid-perfectly plastic model at both element ends. The shear amplification values depend on the coupling level, with the highest amplification values ​​being observed for connected (not coupled) systems. The high values ​​for connected walls are due to the rapid plastification of the wall because of the low structural redundancy. The mean shear amplification values are 1.45, 1.10 and 1.35 for coupling slabs with reinforcing steel ratio of 0.0%, 0.3% and 0.6%, respectively. The proposed expression for the dynamic shear amplification also depends on the response modification factor of the walls, a parameter directly related to nonlinearity sources. On the other hand, an expression used by many codes that depends on the number of floors does not necessarily represent the amplification that occurs in tall buildings with moderate coupling, since the plastification at the base in such cases is difficult to achieve given their large elastic displacement capacity, as well as, cases that incorporate a minimum base shear criterion, that reduce the nonlinearity incursions.

Bolted Gusset Plate Yielding in Special Concentrically Braced Frames

AbstractBased on the authors’ recent findings regarding the Whitmore section and the block shear criteria for determining the ultimate tension resistance of a structural steel-bolted gusset plate, ...

Impact of tensile strength and incident angles on a soil slope under earthquake SV-waves

The tensile strength and incident angles play important roles in seismically induced slope failures. In this paper, a new criterion for tension–shear coupling is proposed based on several sets of relevant lab data and is verified using the experimental data provided by previous researchers. This criterion can perfectly depict the tension region as well as the compression region in the entire stress space. Moreover, the tension–shear criterion was converted into an expression that could be directly used in a numerical method, and it was verified by a numerical example. In addition, the SV-waves were input using the equivalent nodal force method based on a viscous-spring artificial boundary. This process was implemented by the ABAQUS software, and two numerical examples were used to verify this method. Subsequently, based on the proposed new criterion and input method, the impacts of the strength criterion and incident angles on an analysis of seismically induced slope failures were studied. The results indicated that the evaluation of the tension–shear region is extremely important in the analysis of the seismically induced slope failures. The tensile strength of the seismically induced landslides was overestimated by the calculation of Mohr-Coulomb criterion owing to the ambiguous description of the tensile failure or the tension-shear failure, the assessment of the slope stability was thus not conservative. The incident angles of seismic waves affected the travel path and the directivity of slope seismic responses; the sliding displacement of the slope side near the epicenter rose with increasing angles of wave incidence, the critical slip surface deepened, and the hazard aggravated. Therefore, it is important to introduce both the tensile strength and incident angles when evaluating the stability of slopes subjected to seismic loads.

Interplay between wall slip and cavitation: A complementary variable approach

Abstract In this work a stable and reliable numerical model based on complementary variables is developed to study lubricated contacts characterised by slip at one or both surfaces and in the presence of cavitation. This model can be used to predict surface behaviour when cavitation induced by e.g. the presence of surface texture, slip, or a combination of the two is encountered, with varying surface parameters. For this purpose, two different algorithms are coupled to predict the formation of cavitation, through a mass-conserving formulation, and the presence of slip at the wall. The possible slippage is described by a limiting shear criterion formulated using a Tresca model. To show the flexibility of our model, several bearing geometries have been analysed, such as a twin parabolic slider, a cosine profile used to mimic a bearing, and a pocketed slider bearing employed to study the effect of surface texture. We observe that the lubrication performance (i.e. low friction coefficient) can be improved by using materials that promote slippage at the moving wall. The location of the slippage region can be optimised to find the lowest value of friction coefficient. Our theoretical developments and numerical implementation are shown to produce useful guidelines to improve and optimise the design of textured superoleophobic surfaces in the presence of lubricated contacts.

Mesoscopic, magnetic and petrofabric study of the High Himalayan gneisses and leucogranite along oblique and frontal ramps of the Vaikrita Thrust in Satluj and Bhagirathi valleys: Thrust locking and superposed folding

Field, microstructural and anisotropy of magnetic susceptibility (AMS) studies were performed along the oblique thrust ramp of the Satluj river valley and frontal thrust ramp of the Bhagirathi river valley. The presence of asymmetric and sheath folds indicates intense shearing near the thrust. The simple shear gradually decreases with an increase in distance from the thrust and pure shear with upright folds becomes prominent. The AMS studies suggest slightly higher pure shear in the frontal ramp region as compared to the oblique ramp region where oblique slip was predominant. The sense of shear criteria and orientation of superposed folds indicate locking of the thrust. Normal faults are the youngest structure.

Seismic Stability Analysis of Waterfront Rock Slopes Using the Modified Pseudo-Dynamic Method

A modified pseudo-dynamic method is introduced in the paper at first, then geometric model of seismic stability on the waterfront rock slope considering the non-linear twin shear criterion is established. Finally the influence factors on the stability of rock slope are analyzed. The conclusions are drawn that the stability of rock slope decreases as the external loading $$q$$ , rock unit weight $$\gamma$$ , horizontal seismic acceleration coefficient $$k_{h}$$ and vertical seismic acceleration coefficient $$k_{v}$$ increases, and it increases as uniaxial compressive strength $$\sigma_{c}$$ , the water depth $$h_{1}$$ and parameters of rock mass properties $$m_{i}$$ and $$GSI$$ of rocks increases. These conclusions can provide great instruction significance for the future engineering design.

Tension–Shear Experimental Analysis and Fracture Models Calibration on Q235 Steel

Tension–shear loading is a common loading condition in steel structures during the earthquake shaking. To study ductile fracture in structural steel under multiple stress states, experimental investigations on the different fracture mechanisms in Chinese Q235 steel were conducted. Different tension–shear loading conditions achieved by using six groups of inclined notch butterfly configurations covering pure shear, tension–shear and pure tension cases. Numerical simulations were carried out for all the specimens to determine the stress and strain fields within the critical sections. Two tension–shear fracture models were calibrated based on the hybrid experimental–numerical procedure. The equivalent fracture strain obtained from the round bar under tensile loading was used for evaluating these two models. The results indicated that the tension–shear criterion as a function of the shear fracture parameter had better performance in predicting the fracture initiation of structural steel under different loading conditions.