• 한국정밀공학회지
• /
• 제14권7호
• /
• pp.137-143
• /
• 1997

In this study, handling simulation of a passenger car is carried out to see the effects of suspension compliance, roll stabilizef bar and chassis flexibility. The front suspension of the car is a MacPherson strut type and the rear suspension is a multi-link type. The following five DADS models are constructed and compared to verify the effects of suspension compliance and chassis flexibility during lane change. (1) Vdhicle model without hard point compliance and stabilizer, (2) Vehicle model with hard point compoiance, (3) Vehicle model with hard point compliance and stabilizer, (4) Vehicle model with hard point compoiance, stabilizer, and one vibration mode of the chaxxis. (5) Vehicle model with hard point compliance, stabilizer, and three vibration modes of the chassis. The result shows that hard point compliance and stabilizer are significant in roll angle, and the flexibility of the chassis affects the yaw angle and yaw rate.

• Smart Structures and Systems
• /
• 제23권1호
• /
• pp.15-29
• /
• 2019

This paper addresses the problem of damage detection in suspension bridge hangers, with an emphasis on the modal flexibility method. It aims at evaluating the capability and the accuracy of the modal flexibility method to detect and locate single and multiple damages in suspension bridge hangers, with different level of severity and various locations. The study is conducted numerically and experimentally on a laboratory suspension bridge mock-up. First, the covariance-driven stochastic subspace identification is used to extract the modal parameters of the bridge from experimental data, using only output measurements data from ambient vibration. Then, the method is demonstrated for several damage scenarios and compared against other classical methods, such as: Coordinate Modal Assurance Criterion (COMAC), Enhanced Coordinate Modal Assurance Criterion (ECOMAC), Mode Shape Curvature (MSC) and Modal Strain Energy (MSE). The paper demonstrates the relative merits and shortcomings of these methods which play a significant role in the damage detection ofsuspension bridges.

• International Journal of Automotive Technology
• /
• 제8권6호
• /
• pp.745-752
• /
• 2007

In this study, the effects of flexible bodies in vehicle suspension components were investigated to enhance the accuracy of multibody dynamic simulation results. Front and rear suspension components were investigated. Subframes, a stabilizer bar, a tie rod, a front lower control arm, a front knuckle, and front struts were selected. Reverse engineering techniques were used to construct a virtual vehicle model. Hard points and inertia data of the components were measured with surface scanning equipment. The mechanical characteristics of bushings and dampers were obtained from experiments. Reaction forces calculated from the multibody dynamics simulations were compared with test results at the ball joint of the lower control arm in both time-history and range-pair counting plots. Simulation results showed that the flexibility of the strut component had considerable influence on the lateral reaction force. Among the suspension components, the flexibility of the sub-frame, steering knuckle and upper strut resulted in better correlations with test results while the other flexible bodies could be neglected.

• 대한물리의학회지
• /
• 제11권3호
• /
• pp.1-9
• /
• 2016

PURPOSE: The purpose of this study was to identify the effects on flexibility of bridge and plank exercises using sling suspension on an unstable surface. METHODS: The subjects of this study were 20 healthy adults in their 20s (plank=10, bridge=10). Both types of exercise were performed three times per week for a period of four weeks. Each exercise was performed in the front and side direction. Exercise intensity was altered through the use of a sling, which was placed at the knee and ankle. Flexibility at trunk forward flexion and backward extension was measured. The trunk forward flexion was measured at sitting position. The trunk backward extension was measured at prone position. The data were analyzed by Two-way ANOVA. RESULTS: There were significant differences in the pre- and post-test for both the bridge and plank exercise groups. In the bridge exercise, significant differences were shown in the trunk forward flexion and the trunk backward extension (p<.05). In the plank exercise, a significant difference was shown in the trunk backward extension (p<.05). No significant differences were noted in interaction effect or the main effects in either group. CONCLUSION: Bridge and plank exercises on an unstable surface improve flexibility. The bridge exercise improves the flexibility of the forward and backward muscles of the trunk. The plank exercise improves the flexibility of the forward muscles of the trunk. This information would be useful in the development of exercise programs including bridge and plank exercises for improving flexibility and core stability.

• 한국자동차공학회논문집
• /
• 제6권4호
• /
• pp.186-197
• /
• 1998

An analysis of handling performance including the compliance effects is performed. Using the primitive design data of suspension systems, a kinematic model and the three kinds of compliance models are developed. The wheel alignments curves are obtained with the multibody dynamic analysis program ADAMS. The compliance effects of each model are discussed. Since the proposed analysis only requires the raw design data, the better prediction of wheel behaviors is possible in suspension design stage.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.856-860
• /
• 2008

Wire-suspensions in the conventional actuators mechanically support the moving part and guarantee the accuracy of the actuator without tangential tilt actuation. However, such a suspension configuration has considerable stiffness in the tangential tilt direction with two additional wire beams for the tangential tilt. Thus, we performed a design sensitivity analysis for the wire-suspension stiffness of 4-axis actuator and controlled the main parameters such as distance among wire-suspensions and wire-suspension length to allow tangential tilt flexibility. The elasticity of frame PCB that supports the moving part by wire-suspensions was also exploited to improve the flexibility of wire-suspension in the tangential tilt direction. A novel suspension structure was devised by establishing eight wire-suspensions at both sides of the moving part for electrical connection to coils. The magnetic circuit according to the proposed 4-axis actuator using multi-polar magnet and coils was also suggested for the generation of electromagnetic forces in the focusing, tracking, radial and tangential tilt directions.

• Wind and Structures
• /
• 제9권4호
• /
• pp.331-344
• /
• 2006

The cable-stayed-suspension hybrid bridge is a cooperative system developed from the traditional cable-stayed and suspension bridges, and takes some advantages of the two bridge systems. It is also becoming a competitive design alternative for some long and super long-span bridges. But due to its great flexibility, the flutter stability plays an important role in the design and construction of this bridge system. Considering the geometric nonlinearity of bridge structures and the effects of nonlinear wind-structure interaction, method and its solution procedure of three-dimensional nonlinear flutter stability analysis are firstly presented. Parametric analyses on the flutter stability of a cable-stayed-suspension hybrid bridge with main span of 1400 meters are then conducted by nonlinear flutter stability analysis, some design parameters that significantly influence the flutter stability are pointed out, and the favorable structural system of the bridge is also discussed based on the wind stability.

• 한국정밀공학회지
• /
• 제14권1호
• /
• pp.205-213
• /
• 1997

In this study, dynamic analysis of a passenger car is carried out to analyze ride quality over a random road profile. The front suspension of the car is a MacPherson strut type and the rear suspension is a multi- link type. The following five different models are constructed and compared to see the effects of engine vibration and chassis flexibility in the ride quality. (1) one rigid chassis model, (2) a rigid chassis and rigid engine model, (3) a rigid engine and flexible chassis model with one vibration mode, (4) one flexible chassis model with six engine vibration modes and one chassis vibration mode, (5) one flexible chassis model with seven vibration modes and four static correction modes. The result shows that engine vibration modes and the first bending mode of the chassis are important in the ride quality.

• 반도체디스플레이기술학회지
• /
• 제19권4호
• /
• pp.11-17
• /
• 2020

In this study, a new method for fabricating flexible transparent electrodes based on silver nanowire-polymer (AgNW-PEDOT:PSS) composite materials having a mesh pattern formed by a solution-based process without lithography was proposed. By optimizing conditions such as the amount of ultraviolet (UV) photosensitizer injected into the suspension of AgNW and PEDOT:PSS, UV exposure time, and deionized (DI) washing time, a clear and uniform mesh pattern was obtained. For the fabricated AgNW-PEDOT:PSS-based mesh-type electrodes, characteristics such as electrical sheet resistance, light transmittance, haze, and bending flexibility were analyzed according to the mixing ratio of AgNW and PEDOT:PSS included in the suspension. The fabricated mesh electrodes typically exhibited a low electrical sheet resistance of less than 20 Ω/sq while maintaining a high transmittance of 80% or more. In addition, it was confirmed from the results of analyzing the effect of PEDOT:PSS on the characteristics of the mesh-type AgNW-PEDOT electrode that the optical visibility was greatly enhanced by reducing the surface roughness and haze, and the bending flexibility was remarkably improved.

• Wind and Structures
• /
• 제13권5호
• /
• pp.471-485
• /
• 2010

In comparison with the common two-tower suspension bridge, due to the lack of effective longitudinal restraint of the center tower, the three-tower suspension bridge becomes a structural system with greater flexibility, and more susceptible to the wind action. By taking a three-tower suspension bridge-the Taizhou Bridge over the Yangtze River with two main spans of 1080 m as example, effects of structural parameters including the cable sag to span ratio, the side to main span ratio, the deck's dead load, the deck's bearing system, longitudinal structural form of the center tower and the cable system on the aerodynamic stability of the bridge are investigated numerically by 3D nonlinear aerodynamic stability analysis, the favorable structural system of three-tower suspension bridge with good wind stability is discussed. The results show that good aerodynamic stability can be obtained for three-tower suspension bridge as the cable sag to span ratio is assumed ranging from 1/10 to 1/11, the central buckle are provided between main cables and the deck at midpoint of main spans, the longitudinal bending stiffness of the center tower is strengthened, and the spatial cable system or double cable system is employed.