• 자동차안전학회지
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• 제11권1호
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• pp.40-47
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• 2019

First, three point bending analysis for the inclined press door impact beam was carried out to investigate inclination angle effect on the maximum strength with varying support distance. Next, for the system model with spring elements representing body stiffness at door mounting area, the bending structural behavior of impact beam mounted on vehicle was estimated. The mounting distance and inclination angle were changed and the beam bending buckling strength was presumed at the head displacement below which spring stiffness change has little effect on the load. Finally strength ratio to predict the bending buckling strength of impact beam mounted on vehicle from three point bending maximum strength of fixed support distance was suggested.

• 한국기계가공학회지
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• 제19권6호
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• pp.80-87
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• 2020

The currently observed trend in car manufacturing is to increase energy-efficiency by producing lighter cars. This study examines the replacement of particular parts, specifically around the impact beam, with material composites 30% lighter than conventional steel currently used. The shape of the impact beam was determined as the trapezoidal cross-sectional area with central reinforcement, using three-point bending analysis. A prototype was fabricated based on the findings of our study and its performance was evaluated by the three-point bending analysis; 2 ply of aramid applied for its displacement. The performance of the final prototype for the door assembly was evaluated using a side-door strength test, which resulted to measured initial strength of 10.5 KN and intermediate strength of 15.6 KN. This research provides a promising solution for better impact beam manufacturing.

• 한국생산제조학회지
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• 제9권3호
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• pp.62-68
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• 2000

In order to automate straightening process of deflected beams an adaptive three-point bending controller is studies which estimates and controls springback of beams under three-point bending. An analytical load-deflection model for three-point bending of beams with circular cross sections is derived nondimensionally. In spite of variation of material and process parameters this model can be applied to springback estimation by measuring real-time values of reactive load and deflection of the beam. A hydraulic punch stroke controller is designed to take real-time controls of the permanent deflection of the beam. The validity of the proposed system is verified through experiments.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.171-180
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• 2005

Bending performances of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been evaluated using experimental tests combined with theoretical and finite element analyses. A finite element simulation for the three-point bending test was performed. Basic properties of aluminum materials used for initial input data of the finite element simulation were obtained from the true stress-true strain curves of specimens which had been extracted from the Al tube beams. True stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing, and true strains were obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens adhered by aluminum plates were employed fur the bending test. The bending deformation behaviors up to the maximum load described by the numerical simulation were in good agreement with experimental ones. After passing the maximum load, reinforcing plate was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed an excellent bending capability.

• Coupled systems mechanics
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• 제9권4호
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• pp.381-396
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• 2020

Analytical investigation of the fracture of inhomogeneous beam with two parallel lengthwise cracks is performed. The thickness of the beam varies continuously along the beam length. The beam is loaded in three-point bending. Two beam configurations with different lengths of the cracks are analyzed. The two cracks are located arbitrary along the thickness of the beam. Solutions to the strain energy release rate are derived assuming that the material has non-linear elastic mechanical behavior. Besides, the beam exhibits continuous material inhomogeneity along its thickness. The balance of the energy is analyzed in order to derive the strain energy release rate. Verifications of the solutions are carried-out by considering the complementary strain energy stored in the beam configurations. The influence of the continuous variation of the thickness along the beam length on the lengthwise fracture behavior is investigated. The dependence of the lengthwise fracture on the lengths of the two parallel cracks is also studied.

• Steel and Composite Structures
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• 제25권3호
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• pp.327-335
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• 2017

To gain more knowledge of aluminum foam sandwich structure and promote the engineering application, aluminum foam sandwich consisting of 7050 matrix aluminum foam core and 304 stainless steel face-sheets was studied under three-point bending by WDW-T100 electronic universal tensile testing machine in this work. Results showed that when aluminum foam core was reinforced by 304 steel face-sheets, its load carrying capacity improved dramatically. The maximum load of AFS in three-point bending increased with the foam core density or face-sheet thickness monotonically. And also when foam core was reinforced by 304 steel panels, the energy absorption ability of foam came into play effectively. There was a clear plastic platform in the load-displacement curve of AFS in three-point bending. No crack of 304 steel happened in the present tests. Two collapse modes appeared, mode A comprised plastic hinge formation at the mid-span of the sandwich beam, with shear yielding of the core. Mode B consisted of plastic hinge formation both at mid-span and at the outer supports.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.60-65
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• 2007

Local buckling behaviors of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been analyzed using experimental tests combined with theoretical and finite element analyses. For this analysis true stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing. True strains were also obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens reinforced by aluminum plates were employed for the bending test. The bending deformation behaviors up to the maximum load analyzed by the numerical simulation agreed well with experimental ones. After passing the maximum load, reinforcing plate hindering the local buckling of the tube beam was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed the most excellent bending capacity, which could be explained on the basis of the neutral axis shift and the local buckling deformation range.

• Tribology and Lubricants
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• 제31권1호
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• pp.13-20
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• 2015

The impact beam, a beam-shaped reinforcement installed horizontally between the inside and outside panels of car doors, is gaining importance as a solution to meet the regulations on side collision of vehicles. In order to minimize pelvis injury which is the biggest injury happening to the driver and passengers when a vehicle is subject to side collision, energy absorption at the door impact beam should be maximized. For the inner panel, the thrust into the inside of the vehicle must be minimized. The impact beam should be as light as possible so that the extent of pelvis injury to the driver and passenger during side collision of the vehicle is minimal. To achieve this, the weight of the impact beam, has to be optimized. In this study, we perform a design analysis with a goal to reduce the weight of the current impact design by 30% while ensuring stability, reliability, and comparison data of the impact beam for mass production. We conduct three-point bending stress experiments on conventional impact beams and analyze the results. In addition, we use a side-door collision test apparatus to test the performance of beams made of three (different materials: steel, aluminum, and composite beams).

• Coupled systems mechanics
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• 제10권6호
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• pp.509-520
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• 2021

Fiber-reinforced concrete (FRC) is a composite material where small fibers made from steel or polypropylene or similar material are embedded into concrete matrix. In a material model each constituent should be adequately described, especially the interface between the matrix and fibers that is determined with the 'bond-slip' law. 'Bond-slip' law describes relation between the force in a fiber and its displacement. Bond-slip relation is usually obtained from tension laboratory experiments where a fiber is pulled out from a matrix (concrete) block. However, theoretically bond-slip relation could be determined from bending experiments since in bending the fibers in FRC get pulled-out from the concrete matrix. We have performed specially designed laboratory experiments of three-point beam bending with an intention of using experimental data for determination of material parameters. In addition, we have formulated simple layered model for description of the behavior of beams in the three-point bending test. It is not possible to use this 'forward' beam model for extraction of material parameters so an inverse model has been devised. This model is a basis for formulation of an inverse model that could be used for parameter extraction from laboratory tests. The key assumption in the developed inverse solution procedure is that some values in the formulation are known and comprised in the experimental data. The procedure includes measured data and its derivative, the formulation is nonlinear and solution is obtained from an iterative procedure. The proposed method is numerically validated in the example at the end of the paper and it is demonstrated that material parameters could be successfully recovered from measured data.

• 한국산학기술학회논문지
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• 제20권7호
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• pp.166-172
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• 2019

금속 일체형 판재 도어 임팩트 빔 개발을 위해 단면 형상의 최적설계를 진행하였다. 기존의 도어 임팩트는 충격을 흡수하는 강관과 양쪽에 브라켓을 용접하여 자동차에 설치하는 구조로 이루어졌다. 하지만, 브라켓을 설치하기 위한 용접작업은 생산성을 떨어뜨리고 생산단가를 증가시키는 과정이다. 이러한 단점을 극복하기 위해 일체형 판재 도어 임팩트 빔의 개발은 반드시 필요한 공정이다. 본 논문에서는 일체형 판재 도어 임팩트의 단면 형상을 수치해석의 방법으로 제안하는 연구를 진행하였다. 외부 충격에 대한 반력 하중 및 생산성을 고려하여 엔지니어의 직관적인 설계 형상 6가지에 대하여 수치해석을 진행하였다. 객관적인 비교를 위해 3점 굽힘 하중 실험을 모사하는 유한요소해석을 진행하였다. 형상과 치수가 상이한 6가지의 단면 형상 중 최적의 형상을 선정하고, 상세 설계를 위해 단면형상의 높이와 폭의 치수를 변화시키며 해석을 진행하였다. 이를 통해, 일체형 판재 도어 임팩트의 최적의 단면 형상을 제안하였다.