• Transactions of the Korean Society of Automotive Engineers
• /
• v.23 no.6
• /
• pp.633-641
• /
• 2015

The ROM (roll over mitigation) system is a next-generation suspension system that can improve vehicle-driving stability and ride comfort. Currently, mass-produced safety systems, such as ESC (electronic stability control) and ECS (electronic control suspension), enable measurements of longitudinal and lateral acceleration as well as yaw rate through inertial sensor clusters, but they lack direct measurements of the roll angle. Therefore, in this paper, a roll angle estimation algorithm from ESC system sensors and tire normal force has been proposed. Furthermore, this study presents a method for roll over mitigation force distribution between the front and rear of a ROM system. Performance and reliability of the roll angle estimation and roll over mitigation force distribution were investigated through simulations. The simulation results showed that the proposed control algorithm and strategy are reliable during vehicle rollovers.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04b
• /
• pp.525-530
• /
• 1998

The objective of this experiment is to observe the elastic and inelastic behaviors of high-rise reinforced concrete frames with nonseimic details. To do this, a building frame designed according to Korean seismic code and detailed in the Korean conventional manner was selected. An 1:12 scale plane frame model was manufactured according law. Reversed lateral load tests and monotonic push-over test were performed under the displacement control. To simulate the earthquake effect, the lateral force distribution was maintained to be an inversed triangular by using whiffle tree. From the tests, story displacements, lateral story forces, local plastic rotations and the relations between inter-story drift versus story shear are obtained. Based on the test results, conclusions on the characteristics of the elastic and behaviors of a high-rise reinforced concrete frame with nonseismic details are drawn.

• Steel and Composite Structures
• /
• v.5 no.4
• /
• pp.305-326
• /
• 2005

The inelastic buckling behaviour of continuously restrained two and three-span continuous beams subjected to concentrated loads and uniformly distributed loads are studied in this paper. The restraint type considered in this paper is fully restrained against translation and elastic twist applied at the top flange. These types of restraints are most likely experienced in industrial structures, for example steel-concrete composite beams and half through girders. The buckling analysis of continuous beam consists of two parts, firstly the moment and shear distribution along the member are determined by employing force method and the information is then used for an out-of-plane buckling analysis. The finite element method is incorporated with so-called simplified and the polynomial pattern of residual stress. Owing to the inelastic response of the steel, both the in-plane and out-of-plane analysis, which is treated as being uncoupled, extend into the nonlinear range. This paper presents the results of inelastic lateral-torsional and lateral-distortional buckling load and finally conclusions are drawn regarding the web distortion.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.1
• /
• pp.191-199
• /
• 2003

It is known that the distribution of the active earth pressure against a rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the farmer paper, a new formulation was proposed for the nonlinear distribution of active earth pressure on a translating rigid retaining wall considering arching effects. In this paper, parametric study is performed to investigate the effect of ${\phi}, {\delta}$ and wall height on the magnitude and distribution of active earth pressure calculated from the proposed equations. In order to check the accuracy of the proposed formulation, the predictions from the equation are compared with both existing full-scale test results and values from existing equations. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict both the earth pressure distribution and the lateral active earth force on the translating wall. Simplified design charts are also proposed for the modified active earth pressure coefficient and fur the height of application of the lateral active force in order to facilitate the use of the proposed equation.

• Earthquakes and Structures
• /
• v.19 no.4
• /
• pp.273-286
• /
• 2020

The pile group foundation is widely used for gravity pier of high-speed railway bridges in China. If a moderate or strong earthquake occurs, the pile-surrounding soil will exhibit obvious nonlinearity and significant pile group effect. In this study, an improved pushover analysis model for the pile group foundation with consideration of pile group effect is presented and validated by the quasi-static test. The improved model uses simplified springs to simulate the soil lateral resistance, side friction and tip resistance. PM (axial load-bending moment) plastic hinge model is introduced to simulate the impact of the axial force changing of pile group on their elastic-plastic characteristics. The pile group effect is considered in stress-stain relations of the lateral soil resistance with a reduction factor. The influence factors on nonlinear characteristics and plastic hinge distribution of the pile group foundation are discussed, including the pier height, longitudinal reinforcement ratio and stirrup ratio of the pile, and soil mechanical parameters. Furthermore, the displacement ductility factor, resistance increase factor and yielding stiffness ratio are provided to evaluate the seismic performance of soil-pile system. A case study for the pile group foundation of a railway simply supported beam bridge with a 32 m-span is conducted by numerical analysis. It is shown that the ultimate lateral force of pile group is not determined by the yielding force of the single one in these piles. Therefore, the pile group effect is essential for the seismic performance evaluation of the railway bridge with pile group foundation.

• Tribology and Lubricants
• /
• v.22 no.6
• /
• pp.307-313
• /
• 2006

In this paper, a theoretical analysis is carried out to study the effect of viscosity variation with pressure in multiply grooved moving hydraulic spool valves. Analytical expressions for pressure distribution in the clearance and leakage flowrate are obtained solving one-dimensional Reynolds. For constant viscosity, an analytical expression for lateral force is also presented. The results showed that variation of viscosity with pressure affect highly on pressure distribution, leakage flowrate and lateral forces in hydraulic spool valves. Therefore additional intensive studies, including numerical analysis for two-dimensional Reynolds, should be required to investigate detailed lubrication characteristics of spool valves for high pressure.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.04a
• /
• pp.529-536
• /
• 1999

The objective of the research stated herein is to observe th elastic and inelastic behaviors and ultimate capacity of 1 : 5 scale 3-story reinforced concrete frame. Pushover tests were performed to 1:5 scale 3-story reinforced concrete frames without and with infilled masonry. To simulate the earthquake effect, the lateral force distribution was maintained to be an inverted triangle by using the whiffle tree. From the results of tests, the relations between the total lateral load and the roof drift, the distribution of column shears, the relation between story shear and story drift, and the angular rotations at the critical portions of structures were obtained. The effects of infilled masonry are investigated with regards to the stiffness, strength, and ductility of structures. Final collapse modes of structures with and without infilled masonry are compared.

• KCI Concrete Journal
• /
• v.11 no.3
• /
• pp.165-174
• /
• 1999

The objective of the research stated herein is to observe the elastic and inelastic behaviors and ultimate capacity of 1:5 scale 3-story reinforced concrete frame. Pushover tests were performed to 1:5 scale 3-story reinforced concrete frames with and without infilled masonry. To simulate the earthquake effect, the lateral force distribution was maintained by an inverted triang1e by using the whiffle tree. From the test results, the relation ships between the total lateral load and the roof drift, the distribution of column shears, the relation between story shear and story drift, and the angular rotations at the critical portions of structures were obtained. The effects of infilled masonry were investigated with regards to the stiffness, strength, and ductility of structures. Final collapse modes of structures with and without infilled masonry were compared.

• Structural Engineering and Mechanics
• /
• v.76 no.3
• /
• pp.279-291
• /
• 2020

The seismic design of conventional frame structures is meant to enhance plastic deformations at beam ends and prevent yielding in columns. To this end, columns are made stronger than beams. Yet yielding in columns cannot be avoided with the column-to-beam strength ratios (about 1.3) prescribed by seismic codes. Preventing plastic deformations in columns calls for ratios close to 4, which is not feasible for economic reasons. Furthermore, material properties and the rearrangement of geometric shapes inevitably make the distribution of damage among stories uneven. Damage in the i-th story can be characterized as the accumulated plastic strain energy (W_pi) normalized by the product of the story shear force (Q_yi) and drift (δ_yi) at yielding. Past studies showed that the distribution of the plastic strain energy dissipation demand, W_pi/ΣW_pj, can be evaluated from the deviation of Q_yi with respect to an "optimum value" that would make the ratio W_pi/(Q_yiδ_yi) -i.e. the damage- equal in all stories. This paper investigates how the soil type and ductility demand affect the optimum lateral strength distribution. New optimum lateral strength distributions are put forth and compared with others proposed in the literature.

• Geomechanics and Engineering
• /
• v.35 no.5
• /
• pp.555-570
• /
• 2023

In the current study, a series of experimental and analytical evaluations were performed to introduce the horizontal pseudo static coefficient (kh) as a function of the wall configuration and the reinforcement type for analyzing reinforced soil walls. For this purpose, eight shaking table tests were performed on reduced-scale models of integrated and two-tiered walls reinforced by metal strip and geogrid to determine the distribution of dynamic lateral pressure in the walls. Then, the physical models were analyzed using Mononobe-Okabe method to estimate the value of kh required to establish the dynamic lateral pressures similar to those observed in shaking table tests. Based on the results, the horizontal pseudo static coefficient and the position of resultant lateral force (R) were introduced as a function of the horizontal peak ground acceleration (HPGA), the wall configuration, the reinforcement type as well as maximum wall displacement.