• Land and Housing Review
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• v.8 no.3
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• pp.211-221
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• 2017

This study proposed hybrid coupled shear wall in the steel plate insertion method, which is capable of reinforcing the shear strength of the entire wall without increasing wall thickness in the wall-slab apartment buildings. The proposed hybrid coupled shear wall was tested for its effectiveness, shear strength and seismic behavior in experiment. As a test result, the shear strength improvement by the proposed hybrid coupled shear was found effective. Integral-type of steel plate insertion was found more effective than separate-type steel plate insertion. In this case, if the stud enforcement method proposed in this study was used, the shear strength of hybrid coupled shear wall was recommended to calculate using the KBC2016 0709.4.1(3) method. The steel plate inserted in the proposed method was found to have no significant impact on the final fracture behavior and bending strength of hybrid coupled shear wall. The shear strength at the final destruction of the wall was merely about 1/50 of the entire design shear strength. Thus, it is deemed that the wall was over excessively designed regarding the shear force in the existing design method. This finding indicates further study on wall designing to ensure effective and economic designing based on appropriate strength estimation under the destruction mechanism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.784-787
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• 2003

Electrorheological(ER) and magnetorheological(MR) fluid-based dampers are typically analyzed using Bingham-plastic shear model under quasi-steady fully developed flow conditions. A Herschel-Bulkley constitutive shear flow relationship is that the linear shear stress vs. strain rate behavior of Bingham model is replaced by a shear stress that is assumed to be proportional to a power law of shear rate. This power is called the flow behavior index. Depending on the value of the flow behavior index number, varying degrees of post-yield shear thickening or thinning behavior can be analyzed. But it is not practical to analyze the damping force in a flow mode damper using Herschel-Bulkley model because it is needed to solve a polynomial equation. A useful guide is suggested to analyze the damping force in a damper using the Herschel-Bulkley model.

• Journal of Pharmaceutical Investigation
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• v.37 no.3
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• pp.137-148
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• 2007

Using a strain-controlled rheometer [Rheometrics Dynamic Analyzer (RDA II)], the steady shear flow properties of a semi-solid ointment base (vaseline) have been measured over a wide range of shear rates at temperature range of $25{\sim}60^{\circ}C$. In this article, the steady shear flow properties (shear stress, steady shear viscosity and yield stress) were reported from the experimentally obtained data and the effects of shear rate as well as temperature on these properties were discussed in detail. In addition, several inelastic-viscoplastic flow models including a yield stress parameter were employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models was examined by calculating the various material parameters (yield stress, consistency index and flow behavior index). Main findings obtained from this study can be summarized as follows : (1) At temperature range lower than $40^{\circ}C$, vaseline is regarded as a viscoplastic material having a finite magnitude of yield stress and its flow behavior beyond a yield stress shows a shear-thinning (or pseudo-plastic) feature, indicating a decrease in steady shear viscosity as an increase in shear rate. At this temperature range, the flow curve of vaseline has two inflection points and the first inflection point occurring at relatively lower shear rate corresponds to a static yield stress. The static yield stress of vaseline is decreased with increasing temperature and takes place at a lower shear rate, due to a progressive breakdown of three dimensional network structure. (2) At temperature range higher than $45^{\circ}C$, vaseline becomes a viscous liquid with no yield stress and its flow character exhibits a Newtonian behavior, demonstrating a constant steady shear viscosity regardless of an increase in shear rate. With increasing temperature, vaseline begins to show a Newtonian behavior at a lower shear rate range, indicating that the microcrystalline structure is completely destroyed due to a synergic effect of high temperature and shear deformation. (3) Over a whole range of temperatures tested, the Herschel-Bulkley, Mizrahi-Berk, and Heinz-Casson models are all applicable and have an almostly equivalent ability to quantitatively describe the steady shear flow behavior of vaseline, whereas the Bingham, Casson,and Vocadlo models do not give a good ability.

• Advanced Composite Materials
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• v.17 no.3
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• pp.191-214
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• 2008

Polypropylene/layered silicate nanocomposites containing maleic anhydride grafted polypropylene were prepared by melt compounding and their rheological behavior was investigated in shear flow. Transient and steady shear flows were simulated numerically by using the K-BKZ integral constitutive equation along with experimentally determined damping functions under dynamic oscillatory and step strain shear flows. Nonlinear shear responses were predicted with the K-BKZ constitutive equation using two different damping functions such as the Wagner and PSM models. It was observed that PP-g-MAH compatibilized PP/layered silicate nanocomposites have stronger and earlier shear thinning and higher steady shear viscosity than pure PP resin or uncompatibilized nanocomposites at low shear rate regions. Strong damping behavior of the PP/layered silicate nanocomposite was predicted under large step shear strain and considered as a result of the strain-induced orientation of the organoclay in the shear flow. Steady shear viscosity of the pure PP and uncompatibilized nanocomposite predicted by the K-BKZ model was in good agreement with the experimental results at all shear rate regions. However, the model was inadequate to predict the steady shear viscosity of PP-g-MAH compatibilized nanocomposites quantitatively because the K-BKZ model overestimates strain-softening damping behavior for PP/layered silicate nanocomposites.

• Steel and Composite Structures
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• v.23 no.3
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• pp.351-362
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• 2017

This paper presents an experimental study on the behavior of composite floor slab comprised by a new steel sheet and concrete slab. The strength of composite slabs depends mainly on the strength of the connection between the steel sheet and concrete, which is denoted by longitudinal shear strength. The composite slabs have three main failures modes, failure by bending, vertical shear failure and longitudinal shear failure. These modes are based on the load versus deflection curves that are obtained in bending tests. The longitudinal shear failure is brittle due to the mechanical connection was not capable of transferring the shear force until the failure by bending occurs. The vertical shear failure is observed in slabs with short span, large heights and high concentrated loads subjected near the supports. In order to analyze the behavior of the composite slab with a new steel sheet, six bending tests were undertaken aiming to provide information on their longitudinal shear strength, and to assess the failure mechanisms of the proposed connections. Two groups of slabs were tested, one with 3000 mm in length and other with 1500 mm in length. The tested composite slabs showed satisfactory composite behavior and longitudinal shear resistance, as good as well, the analysis confirmed that the developed sheet is suitable for use in composite structures without damage to the global behavior.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.607-614
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• 2010

Shear behavior of granular soils largely affects the safety and stability of underground and earth structures. This study presents the characteristics of shear zone in a direct shear test using shear wave and electrical resistivity measurements. An innovative direct shear box made of transparent acrylic material has been developed to prevent direct electric current. Bender elements and electrical resistivity probe are embedded in the wall of direct shear box to estimate the shear wave velocities and the electrical resistivity at the shear and non-shear zones. Experimental results show that the void ratio and shear wave velocity at shear zone increase during shearing while the values remain constant at non-shear zone. The results demonstrate correlation among the contact force, small strain shear modulus, and void ratio at shear zone. This study suggests that the application of the modified direct shear box including shear wave and electrical resistivity measurements may become an effective tool for analyzing soil behavior at shear zone.

• Steel and Composite Structures
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• v.28 no.1
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• pp.73-82
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• 2018

This paper experimentally and analytically elucidates the shear behavior and shear bearing capacity of partially prefabricated steel reinforced concrete (PPSRC) columns and hollow partially prefabricated steel reinforced concrete (HPSRC) columns. Seven specimens including five PPSRC column specimens and two HPSRC column specimens were tested under static monotonic loading. In the test, the influences of shear span aspect ratio and difference of cast-in-place concrete strength on the shear behavior of PPSRC and HPSRC columns were investigated. Based on the test results, the failure pattern, the load-displacement behavior and the shear capacity were focused and analyzed. The test results demonstrated that all the column specimens failed in shear failure mode with high bearing capacity and good deformability. Smaller shear span aspect ratio and higher strength of inner concrete resulted in higher shear bearing capacity, with more ductile and better deformability. Furthermore, calculation formula for predicting the ultimate shear capacity of the PPSRC and HPSRC columns were proposed on the basis of the experimental results.

• Korea-Australia Rheology Journal
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• v.15 no.3
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• pp.151-156
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• 2003

In this research, experimental studies were performed to examine the rheological behavior of equimolar solutions of cetylpyridinium chloride (CPyCl) and sodium salicylate (NaSal) solutions with concentration. The surfactant solutions were prepared by dissolving 2 mM/2 mM - 80 mM/80 mM of surfactant/counterion in double-distilled water. It has been observed that the zero shear viscosity shows abrupt changes at two critical values of C^*$ and C^{**}$. These changes are caused by the switching of relaxation mechanism with concentration of CPyCl/NaSal solutions at those concentrations. The wall slip velocities of dilute and semidilute CPyCl/NaSal solutions show a dramatic increase with shear rate where the shear viscosity exhibits shear thickening behavior for dilute solutions and shear thinning behavior for semi-dilute solutions, respectively. Considering that the dramatic increase in wall slip velocity should be related to the formation of shear-induced structure (SIS) in the surfactant solution, the shear thickening behavior of semi-dilute solutions is caused by elastic instability unlike the case of dilute solutions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.86-91
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• 2020

An important factor of rough road modeling is analyzing the shear behavior properties of the rough road. These properties influence the drawbar pull of the tool when interacting with the soil used in agriculture. Furthermore, shear behavior properties are important because sinkage and shear stress are generated when wheels drive on rough roads. In this study, we performed a direct shear test to investigate the shear behavior properties of soils and compare with the direct shear simulation; shear force derived by the coupled analysis of discrete element method; and multi-body dynamics. Soil contact parameters were measured in a wheel and soil contact simulation followed by comparison of the simulated and experimentally measured shear force.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.2
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• pp.121-131
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• 2007

Recently, the probability of rock joints being exposed to free faces is getting higher for the scale of rock mass structures gets larger. Also, the frequency of occurring dynamic events such as earthquakes and blasting has been increasing. Thus, the shear behavior of rock joints under different conditions needs to be investigated. In this study, a series of direct shear tests were carried out under various conditions to examine the velocity-dependent shear behavior of saw-cut rock joints. Two types of direct shear test were carried out. The first was to examine the velocity-dependent shear behavior of saw-cut rock joints at seven different shear velocities, each with three different normal stresses. The second was to examine the shear behavior of saw-cut rock joints when three different instantaneous shear velocities changed. As a result, the coefficient of friction was affected by normal stress. The breakpoint velocity, the point when the change of shear velocity starts to affect the frictional behavior, became lower as normal stress increased. Also, as the shear velocity became lower, the degree of stress-drop on stick-slip behavior became larger. As a result of examining the changes of friction coefficient, velocity weakening (decrease of friction coefficient) was observed. The decrement of friction coefficient due to the changes of shear velocity under slow shear velocity was larger than that under fast shear velocity.