• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.8
• /
• pp.955-960
• /
• 1999

This paper describes the effect of impact configurations on a single robot manipulator. The effect of different configurations of kinematically redundant arms on impact forces at their end effectors during contact with the environment is investigated. Instead of the well-known impact ellipsoid, I propose an analytic method on the geometric configuration of the impact directly from the mathematical definition. By calculating the length along the specified motion direction and volume of the geometry, we can determine the characteristics of robot configurations in terms of both the impact along the specified direction and the ability of the robot withstanding the impact. Simulations of various impact configurations are discussed at the end of this paper.

• Fibers and Polymers
• /
• v.1 no.1
• /
• pp.45-54
• /
• 2000

Impact behaviors of the large deformable composites of Kevlar fiber reinforced composites of different preform structures have been investigated. An analytic tool was developed to characterize the impact behavior of the Kevlar composites. The image analysis technique, and deply technique were employed to develop energy balance equation under impact loading. An energy method was employed to establish the impact energy absorption mechanism of Kevlar multiaxial warp knitted composites. The total impact energy was classified into four categories including delamination energy, membrane energy, bending energy and rebounding energy under low velocity impact. Membrane and bending energy were calculated from the image analysis of the deformed shape of impacted specimen and delamination energy was calculated using the deplying technique. Also, the impact behavior of Kevlar composites under high velocity impact of full penetration of the composite specimen was studied. The energy absorption mechanisms under high velocity impact were modelled and the absorbed energy was classified into global deformation energy, shear-out energy, deformation energy and fiber breakage energy. The total energy obtained from the model corresponded reasonably well with the experimental results.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.7
• /
• pp.116-125
• /
• 1997

An investigation was performed to study the impact damage in CFRP laminated composites subjected to impact loading. A finite element model has been developed for predicting the impact damage in laminated composite plates resulting from the ballistic impact. The finite element model was based on the higher-order shear deformation theory and was used to predict the initial intraply matrix cracking and the shape and size of interface delamination in laminated composites. Numerical simulation was performed and then the initiation of the matrix cracking and the shape and size of impacted induced delamination were predicted, and te results were compared with those of impact experiments with the same dimension and stacking sequences. A linear relationship holds between impact velocity and length and width of delamination. As impact velocity is increased, the increase of delamination length is highger than the increase of delamination width.

• Proceedings of the KSR Conference
• /
• 2001.10a
• /
• pp.211-216
• /
• 2001

It is well known that composite laminates are easily damaged by low velocity impact. Low velocity impact damage characteristics and residual compressive strength of composite laminates used in light rail transit are investigated. The damage of composite laminates subjected to impact loading are occurred matrix cracking, delamination, and fiber breakage. The damage of matrix cracking and delamination are reduced suddenly the compressive strength after impact. The objectives of this study is to evaluate impact characteristics and the relationship between impact force and inside damage of composite laminates by low velocity impact loading. UT C-scan is used to determine impact damage areas by impact loading.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11a
• /
• pp.383-386
• /
• 2001

The KS of “Measurements of impact sound insulation of floors” was established before the years. But the KS of “Rating of floor impact sound insulation for impact source in building and of building elements” is not founded yet. To establish the rating measurement of floor impact sound insulation. The studies on the rating method of domestic floor system of impact sound insulation and response of its inhabitant’s were reviewed. And the rating method of ISO’s and JIS’s were studied in this consideration. The result of this study, KS of “Rating of floor impact sound insulation for impact source in building and of building elements” is proposed.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.135-138
• /
• 2003

Recently, sandwich structures have been widely employed in load bearing structures due to their high specific stiffness and high specific strength. Some sandwich structures are subjected to not only static loads but also impact loads which might induce failure of structures at far less load than expected. Since sandwich structures can fail in various modes, estimation of the impact energy absorption is difficult. In this work, the impact failure modes and the impact energy absorption characteristics of the sandwich beams were predicted by the FE analysis and confirmed by the impact test. From the analytic and experimental results, the impact failure mode map was constructed with respect to non-dimensional parameters.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.911-916
• /
• 2008

Impact noise caused by the collision of bodies is difficult to estimate because of the complexity of impact phenomenon. In this study, impact noise is estimated using two different methods when the noise is caused by the vibration due to impact. First, impact noise is analyzed using impact analysis and boundary element analysis. Second, modal expansion technique is applied to the estimation of impact noise. Experiment is carried out to validate the analysis results.

• Journal of Auto-vehicle Safety Association
• /
• v.6 no.2
• /
• pp.12-17
• /
• 2014

The number of vehicle accidents related to the side impact has increased since 1990 in Korea, thus the side impact test has been performed as one of the major vehicle evaluations of the Korean New Car Assessment Program(KNCAP) in 2003. A total of 77 vehicles of eight different types(compact, small, semi-midsize, midsize, and large sedans and small, midsize, and large sports utility vehicles) were tested in side impact and side pole impact conditions. In this study, the head and thorax injury values(HICs and chest deflections) of the side impact tests performed between 2003 and 2013 were investigated in terms of vehicle type, test year, and test condition. The recent vehicles showed better safety performances(lower injury values) and similar injury patterns were obtained between side impact and pole side impact tests.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.812-818
• /
• 2001

The drop type impact test and finite element analysis are established for examining the buckling behavior of a square tube under the lateral impact load. Based on these results, the effects by the boundary conditions for supporting the structure are reviewed, which are as follows. One is pinned condition by screw; the other is fixed by welding. The critical impact force and acceleration by test are nearly same between two cases. However, the critical impact velocity of the pinned condition is higher than that of the fixed case. Therefore, the dynamic buckling behavior of a pinned structure is better than the fixed condition in view of critical impact velocity. These test and analysis results will be adaptable for predicting the dynamic structural integrity of a tube structure not only the axial impact event but the lateral impact event.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.10a
• /
• pp.244-249
• /
• 2011

The potential hazards resulting from a low-velocity impact (bird-strike, tool drop, runway debris, etc.) on aircraft structures, such as engine nacelle or a leading edges, has been a long-term concern to the aircraft industry. Certification authorities require that exposed aircraft components must be tested to prove their capability to withstand low-velocity impact without suffering critical damage. In most of the past research studies unloaded specimens have been used for impact tests, however, in reality it is much more likely that a composite structure is exposed to a certain stress state when it is being impacted, which can have a significant effect on the impact performance. And the radiated impact sound induced by impact is analyzed for the damage detection evaluation. In this study, an investigation was undertaken to evaluate the effect in-plane loading on the impact force and sound of composite laminates numerically.