• Title/Summary/Keyword: Bending

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Sectional Finite Element Analysis of Forming Process of Aluminum Sandwich Sheet by Bending Augmented Membrane Elements (굽힘 첨가 박막요소에 의한 알루미늄 샌드위치 판재 성형공정의 단면 유한요소 해석)

  • 이재경;금영탁;유용문;이명호
    • Transactions of Materials Processing
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    • v.10 no.2
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    • pp.91-100
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    • 2001
  • A sectional FEA program is developed lot analyzing forming processes of sandwich sheets, which are intensively used recently as a lightweight material of an automobile body. The aluminum sandwich sheet consists of two aluminum skins and a polyprophylen core in between. The aluminum sandwich sheet is dominantly effected by the bending effects in small radius of curvature, so that an appropriate description of bending effects is required to analyze the forming processes. For the evaluation of bending effects, the bending equivalent forces are calculated from the bending moment computed using the curvature of the tool and are added to the membrane stretch forces. To verify the validity of the developed program the sectional FEA results in stretch/draw forming Processes of a square cup and draw forming Processes of an outer hood panel were compared with the measurements.

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A Study on Performance-Analysis and Control of the Active Catheter (작동형 내시경의 성능 해석 및 제어에 관한 연구)

  • Cheong, J.P.;Kim, J.H.;Lee, J.M.
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.556-561
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    • 2000
  • This paper deals with the control of an active bending actuator fur a catheter. The bending actuator with 40mm in length utilizes three zigzag SMA (shape memory alloy) springs which are equally located in the circumference between inner $({\phi}2.5 mm)$ and outer $({\phi}3.0mm)$ tube. It is purposed on realization of desired bending angle $(90^{\circ})$ and direction $(360^{\circ})$. It is also installed in front of the catheter and used to guide a path at extremely bent or branched blood vessel. The performance-analysis of the bending actuator are investigated fur the purpose of optimizing the control of the bending actuator. The analog joy stick is used to command a bending angle and direction for the fast and accurate response. According to the commands of the joy stick, tensile force of each SMA spring is computed and obtained by controlling the temperature of each SMA spring using PWM (pulse width modulation) of supplied electric power.

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A Study on the Surface Roughness & Bending Strength for Zirconia Ceramic Grinding (질코니아 세라믹 연삭시 표면조도와 굽힘강도에 관한 연구)

  • 하상백
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.465-470
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    • 2000
  • This paper is concerned with the surface roughness and the bending strength of ground workpiece in ZrO2 ceramic grinding. Surface roughness was measured with surface tracer and bending strength value was obtained by three-point bending test on machining center using tool dynamometer. Grinding experiments were carried out to examine the effects of grinding conditions including diamond mesh size, table speed, and depth of cut on ground surface roughness. The correlation between surface roughness and bending strength was also inspected. The experimental results indicate that the rougher surface was produced as the mesh size of diamond wheel is reduced and table speed is increased, but surface roughness is not affected by depth of cut. The values of bending strength decrease as the values of Ra, Rmax and Ku increase.

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Design of Low Pressure Driven Soft Actuators for Soft Gripper (소프트 그리퍼를 위한 저압 구동 소프트 액추에이터의 설계)

  • Yoon, Jingon;Yun, Dongwon
    • The Journal of Korea Robotics Society
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    • v.16 no.1
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    • pp.23-28
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    • 2021
  • The gripper with a soft pneumatic actuator uses a soft material, unlike the gripper that uses a rigid body, so it is safer and lighter to interact with objects without advanced control technology. Among the soft pneumatic actuators that have been studied, PneuNets actuators have bellows shape, which enable quick operation and complete bending with only small material deformation at low pressure. In this study, we suggested improved form of PneuNets actuators to obtain the performance of the soft actuator that a larger bending angle and larger bending force at a small pressure. An experiment was designed and conducted to measure the bending angle and bending force according to the pressure. As a result, it was confirmed through experiments that the improved model has a maximum bending angle at a pressure of 5 kPa lower than that of the previous model, and a maximum bending force of 1.97 times at the same pressure.

A Study on High Accuracy Bending Work using Servo Control of Bending Machine (Bending Machine의 서보제어에 의한 고정도 굽힘가공에 관한 연구)

  • 송충현;김성식;김경석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.85-90
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    • 2001
  • Recent general Press brake has many problems in cutting high accurate products in the progress of industry. Previous hand-operated press brake needs many pre-processing works to adjust bending ang1e and marking-off works to calculate bending length. Also, the hand-operating work makes many geometric errors and has difficulty for variety-mass production. To solve these problems, this paper proposes Computer Numerical Control (CNC) general press brake and development of servo-control system based on database for reduction of geometric errors and pre-processing work time and high accuracy bending work.

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Direct Missile Bending Frequency Estimation using the Robust Kalman Filter (강인 칼만필터를 이용한 유도탄 기체 진동 주파수 추정기 설계)

  • Ra, Won-Sang;Whang, Ick-Ho
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2477-2479
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    • 2005
  • A robust bending frequency tracker is proposed to design the adaptive notch filter which removes the time-varying missile structural modes from the sensor measurements. To do this, the state-space form of a bending frequency model is derived under the assumption that the bending signal could be described as the lightly damped sinusoid. Since the resultant bending frequency model contains the parametric uncertainties in the measurement matrix, the design problem of bending frequency tracker is tackled by applying the robust Kalman filter to the model. This technique could be easily expanded to the multiple frequencies case because it newly illuminates the bending frequency tracking problem in view of general state estimation.

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The Bending minimization of Joint Shat in Cross rolling

  • Park Joon Soo;Lim Seong Joo;Yoon Duk Jae;Choi Seogou
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10b
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    • pp.107-114
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    • 2003
  • Although cross rolling process has many advantages in forging a joint shaft, an automotive component of front axle unit, subsequent process is necessary to straighten its bending during forging process. In this paper the bending minimization of the joint shaft was studied to eliminate such an additional process. First of all, a characteristic diagram was used to find out factors affecting the bending of the shaft. Also design of experiments was utilized for estimating the influence of those factors. It was found that the phase angle, which is the difference in starting positions between upper and lower dies, was important to minimize the bending of joint shaft and die cooling is necessary to diminish the distribution of bending.

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The Thinning Phenomena of the Wall Thickness during $360^{\circ}$ Cold Bending of Ti-6Al-4V Large-Diameter Seamless Tube (대 직경 이음매 없는 Ti-6Al-4V 합금 튜브의 $360^{\circ}$ 냉간 굽힘 시 벽두께 감소현상)

  • 허선무;박종승
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.1
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    • pp.231-236
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    • 2000
  • The wall thickness of the Ti-6Al-4V Large-Diameter Seamless Tube, which is supposed to be a very important parameter in a system design, was measured during $360^{\circ}$ cold bending processes. The factors or processes affecting the wall thickness include 1) primary bending, 2)secondary or finishing step of the $360^{\circ}$ bending, 3)cleaning processes in CERO TRUTM(CT)process. But thinning effects of the wall thickness during the cleaning processes are negligible compared to those during the formers. The variations in the percentages of the change in wall thickness were found to be from -14% to +16%.

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$360^{\circ}$ Cold Bending of Ti-6Al-4V Large-Diameter Seamless Tube (대 직경 이음매 없는 Ti-6Al-4V 튜브의 $360^{\circ}$ 냉간 굽힘)

  • 허선무;박종승
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.1
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    • pp.176-182
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    • 2000
  • $360^{\circ}$ bending of Ti-6Al-4V large-diameter seamless tube(62.37 mm $OD {\times} 4.40mm$ wall thickness) has been achieved at room temperature without heating. The bending process comprised two steps : the first step is $360^{\circ}$ bending by an uniquely designed rotary bender allowing spring back, which is subsequently eliminated by the second or finishing step which comprised repeated bending processes by powered three roll bender, In odor to prevent collapse of tube during bending, Cerro $Tru^{TM}$(Trade name of a non-ferrous low melting point alloy)has been employed as a filler metal. The resultant ovality(out of roundness) obtained was 1.28%, as compared with 6~8% without applying Cerro $Tru^{TM}$.

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Proposal of bulged-type abrupt bend structure with low bending loss (굽음손실이 적은 Bulged형 Abrupt Bend 구조의 제안)

  • 한상필;김창민
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.8
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    • pp.71-79
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    • 1997
  • Bulged-type bends with low bending loss are newly proposed, and the FD-BPM is made use of for designing optimum structure. How to evaluate bending loss of conventional bends and how to improve the bending structure based on the phase compensation concept are described in genral. Besides simulation results for the bulged-type bends, results for the coupled-type bends and the chamfered-type bends show the most superior performance in terms of not only the bending loss but also the design tolerance.

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