Maximum Shear Force Research Articles

Finite element analysis of the soil and foundations of the Al-Kufa Mosque

Abstract The Great Mosque of Kufa, built in 639 CE and located in Al-Kufa, Iraq, is considered one of the most important mosques in the Islamic world. Because cracks appeared in the historical walls of the Al-Kufa Mosque during the construction of the Muslim Bin Aqeel Underpass, the values and locations of bending moment and shear force may be useful for wall maintenance. So, this study aims to determine the maximum and minimum values and locations of settlement, bending moment, and shear forces under the mosque walls’ foundations. Historical references are used to know the previous architectures of the mosque. Also, archaeological investigation reports are adopted to find out the characteristics of the foundations like their dimensions, depths, and materials. Soil investigation reports are used to know the soil layer’s properties and parameters. For non-mentioned soil parameters in soil investigation reports, they are determined depending on the theoretical equations, charts, statistical correlations, and models. A model of soil layers, foundations, and walls is conducted and analyzed using finite element software to determine the deformations of soil layers under the mosque’s brick foundations and walls. According to the analysis, maximum bending moment and shear force were found under the minaret near the Al-Thuaban gate.

Numerical Study on Connections of Replaceable Shear Link with Inserted Pins

The link end plate of replaceable shear link in eccentrically braced frames has been modified with the ‘inserted-pins’ to ensure the high seismic performance and to reduce the number of bolts in its slip-critical connections. The maximum shear force in the connection is resisted by the pins, while the bolts resist the bending moment at the link-ends. Numerical work has been conducted using a non-linear ABAQUS program to study the deformation as well as the stress distribution of the shear-link and its connection elements: end plates, bolts, pins, and beam-outside the link. The results showed an adequate performance of the proposed modified shear link connections, where the end plate of the beam outside the link remained elastic as the shear-link reached 0.08 rad plastic rotation due cyclic loading.

Seismic Resistance Building Using Eccentric Braces In Infill Structure at Soft Story Level A Review

A soft story or a weak story is one in which the lateral stiffness is less than 70 percent of that in the story above or it can be less than 80 percent of the average lateral stiffness of the three stories above. For the reduction of lateral deflection of a structure, a bracing system is provided. In seismic design of structure and in high rise structure, the provision of bracing system has become more effective. So, this paper aims to find out the effect of bracing on soft story of steel building. In this paper, G+7 steel frames are modeled with different type of bracing pattern and different combination of soft story using software STAAD Pro. Effect of these different bracings on soft story is studied for different parameter like column displacement, maximum deflection, story drift, maximum bending moment, maximum axial force and maximum shear force. From the observed result best type of bracing will be selected.

Effect of fluoride varnish in combination with simulated oral environment on enamel-bracket shear bond strength.

To determine the effect of fluoride varnish application combined with a simulated oral environment prior to bracket bonding on the shear bond strength (SBS) between brackets and tooth enamel. Sixty de-identified, extracted teeth were grouped to either receive or not receive fluoride varnish and then stored for 7 days at 37°C in phosphate-buffered saline (PBS) solution or PBS combined with three 15-min cycles/day in a demineralizing solution to simulate pH variation following meals. Subsequently, brackets were bonded and after 24-h dark cure at 37°C, debonded using shear forces in a simulated oral environment. The maximum shear force was used to calculate SBS, and the adhesive remnant index (ARI) was determined by image analysis of photos of the bracket mesh pad after debonding. A statistically higher SBS (10.16MPa) was observed when fluoride varnish was applied prior to storage in PBS + demineralizing solution compared to SBS (6.38MPa) following storage in the same solution without varnish application. Based on 37% effect size, this difference is also clinically relevant. In contrast, no significant differences in SBS were observed with varnish application combined with PBS with no demineralizing solution or between storage solution alone. Moreover, there was no significant difference in ARI due to varnish combined with either storage method or storage solution only. Results suggest varnish application prior to bracket bonding in combination with simulated oral environment that included acid exposure is beneficial in maintaining higher SBS between bracket and enamel. Despite higher SBS, adhesive remaining on enamel did not increase.

Castellated steel beams under impact load

This study explored the impact of irregular dynamic loads on castellated steel beams (CSBs) by conducting drop weight impact tests and establishing a numerical model using the nonlinear finite element method. The numerical simulation results were compared with the test results of the impact to verify its validity and analyze the buckling process and stress development of the CSB under impact load. Results showed that during the impact process, the maximum shear force was achieved first, followed by maximum bending moment and maximum deflection, respectively. It was observed that the increase in impact velocity and impact mass were unfavorable to the deflection of the CSBs, and resulted in an increase in the time required to dissipate impact energy. Furthermore, the ratio of spacing between openings to beam height exhibited a minor impact on the deflection in the range of 1.083–1.75. The ratio of opening height to beam height mainly affected the deflection near the midspan of the CSBs in the range of 0.5–0.7. The impact location significantly influenced the shape of the deflection curve. The larger the span-height ratio was, the more unfavorable it was for the CSBs to resist the impact. In addition, while the clamped support boundary condition reduced CSB deflection, it resulted in a rather substantial bending moment at the CSB ends. Based on the support rotation value as the damage evaluation index, a damage assessment curve with impact velocity and impact mass as the main control parameters was established.

Finite Element Model Construction and Cutting Parameter Calibration of Wild Chrysanthemum Stem

Due to a lack of an accurate model in finite element simulation of mechanized harvesting of wild chrysanthemum, the stem of wild chrysanthemum in the harvesting period is taken as the research object. ANSYS Workbench 19.0 software and LS-DYNA software (LS-PrePOST-4.3-X64) are used to calibrate the finite element simulation model of wild chrysanthemum stem cutting. The stem diameter distribution at the cutting height of the chrysanthemum is obtained. The maximum shear forces at different diameters (7 mm, 8 mm, 9 mm, 10 mm, and 11 mm) within the cutting range are determined as 120.0 N, 159.2 N, 213.8 N, 300.0 N, and 378.2 N, respectively, by using a biomechanical testing machine and a custom-made shear blade. The Plastic_Kinematic failure model is used to simulate the cutting process by the finite element method. The Plackett–Burman test is employed to screen out the test factors that significantly affect the results, namely, the yield stress, failure strain, and strain rate parameter C. The regression model between the shear force and significant parameters is obtained by central composite design experiments. To obtain the model parameters, the measured values are substituted into the regression equation as the simulation target values. In other words, the yield stress is 17.96 MPa, the strain rate parameter C is 87.27, and the failure strain is 0.0387. The maximum shear force simulation test is carried out with the determined parameters. The results showed that the maximum error between the simulated and the actual value of the maximum shear force of wild chrysanthemum stems with different diameters is 7.8%. This indicates that the calibrated parameters of the relevant stem failure model can be used in the finite element method simulation and provide a basis for subsequent simulations.

Slope topographic impacts on the nonlinear seismic analysis of soil-foundation-structure interaction for similar MRF buildings

Seismic waves reflected from slope surface amplify ground surface motions in the area near the crest. Therefore, the seismic response of structures considering seismic topography-soil-structure interaction (TSSI) is different from their response considering soil-structure interaction (SSI). This paper investigates the seismic performance of three groups of moments resistant frame (MRF) steel structures with 5, 10, and 15 stories through the three-dimensional (3D) numerical simulations. In each case of TSSI, these buildings with similar dynamic characteristics are modeled simultaneously at various distances from the crest. The inelastic performance of MRF components was simulated using the plastic hinges. Also, the nonlinear soil performance was considered by a hardening elasto-plastic hysteretic model, i.e., the constitutive model of the hardening soil with small-strain stiffness (HSsmall). Results show that the topographic irregularities magnify the acceleration at a distance of 2–3 times the slope height (H) from the slope crest. Moreover, the greatest impact of topography on the seismic responses is found for the building near the slope crest. Results also demonstrate the seismic response of 5-storey buildings is very little affected by slope topography. On the other hand, slope topography significantly intensifies the seismic responses of 10 and 15-storey buildings. According to the TSSI analysis, the maximum lateral displacements of 10 and 15-storey buildings are increased by 10%–125% compared to the SSI analysis. Besides, maximum base shear forces for both buildings increased more than three times.

Discrete element modelling of the yam root–soil complex and its verification

This paper constructs a discrete element simulation model of yam based on a bimodal model and uniform grid coordinates and performs parameter calibration on the simulation model based on three mechanical properties. The bonding parameters are: normal stiffness per unit area 8.0684 × 107 N·m−3, shear stiffness per unit area 2.0314 × 107 N·m−3, critical normal stress 1.2876 × 107 Pa and critical shear stress 8.9623 × 107 Pa. Using the root–soil complex shear test, based on the grey correlation analysis method, a root morphology index with the greatest correlation with the maximum shear force of the yam root–soil complex was obtained. The factor that has the greatest influence on the maximum shear force of the root–soil complex is the total surface area of the root, the correlation degree is 0.77. The root–soil complex bond parameters are as follows: normal stiffness per unit area 5.203 3 × 105 N·m−3, shear stiffness per unit area 2.493 8 × 106 N·m−3, the critical normal stress 1 × 105 Pa and the critical shear stress 5.319 0 × 105 Pa. The accuracy of the simulation model of the yam root–soil complex was verified by comparing the simulation test with the physical test. The relative error of the axial compression rupture pressure value of the yam root–soil complex simulation test and the physical test is 6.63%, the relative error of the displacement value is 8.83%, the relative error of the radial compression rupture pressure value is 6.83%, and the relative error of the displacement value is 6.38%.

Analisis Kinerja Kolom Pipih dan Kolom Konvensional pada Bangunan Bertingkat Rendah

Unconventional columns are very familiar in modern building construction because they impact the room's efficiency. Meanwhile, conventional columns affect the lack of efficiency in the room's functions. The performance analysis of the two types of columns used pushover analysis of the capacity spectrum method using ETABS v 16.1.0 software. The performance level results of the two types of columns in low-rise buildings are the same, which is Immediate Occupancy. The most significant maximum shearing force is at a low-rise building with an unconventional column with a maximum displacement on the east side of 160,00 mm. The smallest is a low-rise building with a conventional column in the east direction with maximum displacement on the Nort side of 90,11 mm. Thus, comparing the performance of the two types of columns can be concluded that conventional columns are stronger than unconventional columns.

Kinematic response of vertical and batter pile groups in non‐linear soft soil

AbstractThis paper presents a comprehensive numerical study on kinematic response of vertical and batter pile groups in soft soil, where soil non‐linearity, batter angle, pile spacing and excitation frequency are related to pile‐cap displacements, rotations, maximum pile moments, shear forces and axial forces. The finite element model is constructed in OpenSees MP, and parallel computing is utilized for a better (faster) performance. Results reveal that soil non‐linearity has a profound impact on the kinematic interaction. Increasing batter angle decreases horizontal displacements but increases rotations. Batter pile groups yield lower spectral accelerations compared to vertical pile groups. For high , the spectral accelerations of the pile‐cap may be lower compared to the spectral acceleration of the seismic input motion. Estimation using non‐linear interaction factors conservatively estimates pile‐cap displacements and rotations, while roughly captures the effects with respect to batter angle and frequency content within the specified framework.

Revisiting the design of the rivet chamfered ends in double-sided self-pierce riveting

As an innovative joining method, double-sided self-pierce riveting (DSSPR) shows great potential in sheet joining area due to its high connection strength, smooth joining surface, simple die structure, etc. By modifying the process, such as the use of rivets with different angles or two-stroke riveting method, dissimilar materials with great difference in mechanical property can be joined successfully. However, the chamfered angle is always at the outermost side of the rivet in previous studies, and its effect has not been paid attention to. In this paper, the chamfered angle position was proposed and studied as a design parameter of tubular rivet for the first time. DSSPR processes with a combination of three chamfered angles and five chamfered angle positions were carried out, and then a single-lap shear test was performed to evaluate the joint strength. Results showed that the chamfered angle position had a significant influence on the riveting force, final rivet morphology, shear strength, and failure mode. When the chamfered angle was 30° and 45°, the maximum shear force for the case of l=0.25 was 82.53% and 51.21% higher than that of the traditional tubular rivet, respectively. In addition, the failure modes during the DSSPR process were analyzed and summarized, and the development process of the three failure modes was discussed. The results can provide theoretical guidance for tubular rivet parameter design in the DSSPR process and its further engineering application.

Integration of reginal shear measurements at the foot-ground interface during routine balance assessment of the elderly population

BackgroundForce-plate posturography offers a convenient way for quantitative assessment of postural stability in the elderly. However, studies focusing on routine balance assessment have usually not taken reginal shear distributions (i.e., arising from horizontal forces) into consideration. Research question(1) Does plantar shear distribution differ between young and elderly subjects during upright standing? (2) How do the maximum plantar shear forces vary at different regions of the foot? MethodsThe new reginal shear measurement (RSM) method can simultaneously capture the three-dimensional force distributions at regional plantar sites while subjects maintaining standing balance. The feasibility of the proposed method in characterizing the magnitude and distribution of plantar shear forces was tested in thirty-two normal young and nineteen elderly subjects. Statistical analysis was performed using the independent samples t-test for both the continuous and ordinal variables. ResultsFor regional AP shear forces, statistically significant differences were found between the two groups for the toe region of the right foot and the midfoot of both feet. For ML shear distributions, statistically significant differences were found at nearly all plantar sites expect for the hallux and lateral metatarsal. The maximum increase in ML shear forces occurred in the toe region of the right foot, where the peak shear values were 113.16% higher than those of the young subjects. The peak ML shear occurred in the midfoot were averagely 83.19% and 70.57% higher in the elderly’s left and right feet, respectively. SignificanceThe RSM method may offer unique solutions to identify functional decline in postural control of the elderly. The plantar shear pattern has potential to become an important parameter in evaluating one’s balance performance during upright standing.

Analytical Prediction of Strip Foundation Building Response to Shallow Tunneling Considering the Tunneling Process

This paper presents an analytical method to predict the response of a strip foundation building to shallow tunneling based on the two-stage method. The existing building is simplified as a Euler–Bernoulli beam resting on the Pasternak model. The tunneling process and different relative positions between the tunnel and the existing building can be considered in the proposed method. The accuracy of the proposed method is verified through comparisons with results from the finite element and finite difference methods. The results indicate that the differential settlement of the building reaches a maximum and the rotation angles are symmetric with respect to the building centerline when the tunnel face arrives at the middle of the building. The maximum bending moments occur at the middle of the building, while the maximum shear forces occur at about one-fifth and four-fifths of the building length when the tunnel face is located at the two ends of the building. According to the parametric analysis, the alignment angle, elastic modulus and Poisson’s ratio of the soil, bending stiffness, and gap parameter greatly affect the building response.

ANALYSIS AND DESIGN OF MULTI-STOREYED (G+2) RESIDENTIAL BUILDING

Structural design is an investigation method of the rigidity, strength and stability of the building. The essential aim in structural analysis and design is to construct a structure capable of overcoming all applied loads without failure during its intended life. This project attempts to understand the structural behavior of various components in the multi-storied building. planning, analysis, designing of multi-storied building has been taken up for residential building (G+2). Thereby depending on the suitability of plan, layout of beams and positions of columns are fixed. Dead loads are calculated based on material properties and live loads are considered according to the code IS875-part 2, footings are designed based on safe bearing capacity of soil. For the design of columns and beams analysis is done by limit state method to know the moments they are acted upon. Slab designing is done depending upon the type of slab (one way or two way), end conditions and the loading. From the slabs the loads are transferred to the beams, thereafter the loads from the beams are taken up by the columns and then to footing finally the section is checked for the components manually and using STAAD Pro V8i software for the analysis of structure, maximum shear force, maximum bending moment are computed.

Ram Performance and Hydraulic Modeling of Subsea Blowout Preventer Control System

Summary A subsea blowout preventer (BOP) system is critical in providing safe working conditions for drilling activities in deepwater oil exploration. However, performance evaluation of the shear ram BOP is still a challenge for the industry. In this paper, two aspects of BOP shearing capability are studied: The required shear force to cut the pipe inside BOP successfully and the time it takes to shear the pipe and close the well. A finite element model is used to calculate the maximum shear force of a typical drillpipe, while an analytical hydraulic model is proposed to calculate the BOP closing time. A case study is presented for estimating the emergency disconnect sequence time in a deepwater offshore scenario. It is assumed that the BOP control system is activated from the surface, employing an electrohydraulic multiplexed control device for closing the BOP and rapidly disconnecting the lower marine riser package (LMRP), thus preventing damage to both riser and wellhead.

Seismic Analysis of Baffle-Reinforced Elevated Storage Tank Using Finite Element Method

The sloshing phenomenon is an important field of fluid dynamics in liquid storage tanks under earthquake excitation. When the sloshing frequency gets close to the liquid tank’s natural frequency, the resulting resonance could lead to instability and even damage to structures, followed by catastrophic economic losses and environmental damages. As passive control devices, baffles are a place for liquid energy dissipation. This study uses annular and horizontal baffles to evaluate the baffles’ relative effectiveness on the elevated storage tanks’ dynamic response. The analysis results are compared with those of elevated storage tanks with no baffles. The flexible and rigid storage tank analysis is examined here, where half of the tank height is filled with liquid. The structural interaction between the liquid, the (horizontal and annular) baffle, and the elevated storage tank affected by seismic action are investigated using Abaqus software. The results confirm that using the baffles, the maximum base shear force in flexible and rigid elevated storage tanks decreases as much as 26.43% and 31.90%, respectively, and the maximum hydrodynamic pressure reduction in the tank is 50.1%.

Moisture influence on structural responses of pavement on expansive soils

Expansive soils are prone to heave and shrinkage due to changes in their natural moisture content. It would be helpful to predict distresses in pavement induced by heave/shrinkage because of long-term moisture variations in the subgrade considering specific environmental conditions. The virtual load method (VLM) has recently been developed to identify virtually distributed load that produces an equivalent deflection of the pavement caused by heave/shrinkage of expansive subgrade soils. In this research, a pavement section of interstate highway 220 (I-220) in Northern Louisiana is considered to implement the VLM and analyze structural behavior due to natural migration of water in unsaturated soil layers. Heave/shrinkage of the soils is computed from the predicted moisture content changes in subgrade using software VADOSE/W. In applying the Winkler’s model in the inverse theory to identify expansive soil-induced stresses in the pavement, a new iteration algorithm is proposed to consider the pavement-soil interaction. Special attention is drawn to the location of absolute maximum shear forces and bending moments in the pavement and their influences on the subgrade deformation. The effects of pavement stiffness and swelling pressure of the subgrade expansive soils are presented to understand the behavior of pavement on expansive soils.

Anti-collapse behavior of modular steel buildings with corrugated panels

This paper numerically studies the anti-collapse behavior of the modular steel building (MSB) in the scenario of interior module removal and corner module removal. The vertical displacement, lateral displacement and internal force of a six-storey MSB in a sudden module loss are studied. The reasonability by using rigid body assumption in collapse analysis of the MSB is examined. A refined fracture model of the steel is incorporated into ABAQUS via user subroutine, in which the effects of both stress triaxiality and Lode angle on the fracture ductility of the steel are considered. In the pushover analyses, the effects of the horizontal connection, opening of the wall panel and thickness of the wall panel on the collapse resistance and failure mode of the MSB are studied. The dynamic amplification factor (DAF) of the MSB at the collapse limit state is also obtained. It is found that the rigid body assumption may significantly underestimate the displacement and maximum shear force in the horizontal connection of the MSB. Two types of failure modes of the structure are observed, namely, connection failure-induced collapse and module unit failure-induced collapse. Among the studied parameters, the effect of the opening size of the wall panel on the behavior of the structure is the most significant. In the scenario of the interior module removal and corner module removal, the DAFs of the structure at the collapse limit state range from 1.20–1.29 and 1.27–1.50, respectively.

Joint formation mechanism and performance of resistance butt spot welding for AA 5754 aluminum alloy sheet

AA 5754 aluminum alloy sheets were successfully joined by using resistance spot welding in butt configuration. The newly proposed welding method changed the heat balance conditions during the welding process, thereby affecting the macroscopic morphology of the nugget. The nugget exhibited an irregular “ellipsoidal shape”. Microstructures and mechanical properties of the butt joints have been investigated. The butt joint could obtain larger shear force than lap joint due to the larger diameter of the nugget under the same welding parameters. The joint fractured at the interface zone with the maximum shear force of 2888 N.

Seed pumpkin flour as a dietary fiber source in Bologna‐Type sausages

Seed pumpkin flour (SPF) obtained from the species Cucurbita pepo was used as a dietary fiber source in bologna-type sausage production at levels of 1.5%, 2.2%, and 3%. There was a significant decrease in emulsion stability of batters containing SPF (p < .05), while a significant increase in jelly-fat separation, viscosity, and WHC (p < .05). Thiobarbituric acid reactive substances (TBARS) and color (L*, a*, b*) values significantly increased in the end-product with the increasing level of SPF, and this tendency continued during the 28-day storage period at 4°C (p < .05). Hardness and adhesiveness values significantly increased, while chewiness, cohesiveness, and resilience values decreased (p < .05). Maximum shear force, work of shear, and work of penetration values of the samples which contain SPF were significantly lower than the control samples (p < .05). SPF did not have any negative effect on sensory properties. These results suggested that the SPF could be used as a dietary fiber source in meat products. Novelty impact statement Research on the use of waste is of great importance both from an environmental and economic point of view. After the seeds are separated from the seed pumpkin, the remaining part such as peel, mesocarp, endocarp, and small seeds is thrown away as a very significant amount of waste. This amount constitutes approximately 92–95% of the seed pumpkin. Considering this ratio, tons of waste material are produced. These wastes are generally left to rot in the harvested areas and cannot be used sufficiently. This situation causes great damage to the economy of the country and the environment. Thus, research on the use of waste is of great importance both environmentally and economically. In this research, pumpkin flour was obtained from the waste material of seed pumpkin, its dietary fiber content was revealed for the first time and it was used as a dietary fiber source in the production of bologna-type sausage.