• 제목/요약/키워드: Deformation load

검색결과 2,365건 처리시간 0.036초

Equal Channel Angular Pressing 가공 중 소성 변형에 미치는 재료의 초기 형상 효과 (Preform Effect on the Plastic Deformation Behavior of Workpieces in Equal Channel Angular Pressing)

  • 윤승채;서민홍;김형섭
    • 소성∙가공
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    • 제15권5호
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    • pp.382-386
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    • 2006
  • Preform design is an effective means of achieving the homogeneous deformation of workpiece materials and decreased load in metal forming. However, this approach has not been applied to equal channel angula. pressing (ECAP). In this paper, plastic deformation behavior of workpieces having four different preform shapes during ECAP was investigated using finite element analyses. The results indicated that a preform design of the workpiece head has a beneficial effect on homogeneous deformation, reducing the maximum pressing load at the initial stage and eliminating folding defects at strain concentration points.

유한요소해석을 이용한 마늘 수확기 굴취부의 응력분석 (Finite Element Analysis Approach for the Stress of Digging Part of Garlic Harvesters)

  • 김규봉;이명희;김대철;조용진
    • 한국기계가공학회지
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    • 제19권11호
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    • pp.78-86
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    • 2020
  • A stress analysis was performed to verify the stability of the digging part of a garlic harvester. A finite element analysis was performed to examine the distribution and concentrated loads on the digging part of the blade and contact plate. Moreover, the stability and maximum deformation of the digging part were determined. Under a distributed load, the maximum principal stress, total deformation, and minimum safety factor ranged from 64-128 MPa, 0.35-0.70 mm, and 2.9-5.7, respectively. The analysis results for the distribution load indicated that the maximum stress occurred at the center of the blade. In contrast, under the concentrated load, the maximum principal stress, total deformation, and minimum safety factor ranged from 66-247 MPa, 0.35-0.79 mm, 1.48-5.53, respectively. The analysis results for the concentrated load indicated that stress and deformation were larger toward the edge and center, respectively.

Seismic performance of Bujian Puzuo considering scale ratio and vertical load effects

  • Yong-Hui Jiang;Jun-Xiao He;Lei Zhu;Lin-Lin Xie;Shuo Fang
    • Structural Engineering and Mechanics
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    • 제90권5호
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    • pp.447-458
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    • 2024
  • This study investigated the influence of scale ratio and vertical load on the seismic performance of Puzuo joints in traditional Chinese timber structures. Three low-cyclic reversed loading tests were conducted on three scaled specimens of Bujian Puzuo in Yingxian Wooden Pagoda. This study focused on the deformation patterns and analyzed seismic performance under varying scale ratios and vertical loads. The results indicated that the slip and rotational deformations of Bujian Puzuo were the primary deformations. The scale of the specimen did not affect the layer where the maximum interlayer slip occurred, but it did decrease the proportion of slip deformation. Conversely, the reducing vertical load caused the layer with the maximum slippage and the position of the damaged Dou components to shift upward, and the proportion of slip deformation increased. When the vertical load was decreased by 3.7 times, the maximum horizontal bearing capacity under positive and negative loadings, initial stiffness, and energy dissipation of the specimen decreased by approximately 60%, 58.79%, 69.62%, and 57.93%, respectively. The horizontal bearing capacity under positive loading and energy dissipation of the specimen increased by 35.63% and 131.54%, when the specimen scale was doubled and the vertical load was increased by 15 times.

단일볼트 지압접합부의 힘-변형관계 (Load-Deformation Relationship of Single Bolted Connections)

  • 김대경;이철호;진승표;윤성환
    • 한국강구조학회 논문집
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    • 제29권5호
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    • pp.341-352
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    • 2017
  • 강구조물을 접합하는 대표적인 두 가지 방법으로는 용접접합과 볼트접합이 있다. 이중 잘 접합된 볼트접합은 지압메카니즘에 의한 강도상승과 연성거동을 기대할 수 있다. 이러한 볼트접합부의 연성능력을 충분히 활용하기 위해 본 연구에서는 합리적인 단일볼트접합부의 힘-변형관계 및 지압강도 산정식을 제안하고자 하였다. 볼트접합부의 경계조건 및 기하학적인 요소를 고려하여 체계적으로 단일볼트 실험을 수행하였다. 현행 설계기준의 볼트접합부의 지압강도 산정식의 모순점을 해결하기 위해 새로운 지압강도 설계식 및 변형한계 산정식을 제안하였다. 또한 접합부의 강성, 강도, 기하학적 조건 등을 반영할 수 있는 힘-변형관계식을 제안하였다. 본 연구에서 제시한 지압강도식 및 힘-변형관계식은 현행설계기준보다 합리적으로 실험결과를 예측하였다.

반목하중으로 인한 지반의 변형 예측 (Approximate Prediction of Soil Deformation Caused by Repeated Loading)

  • 도덕현
    • 한국농공학회지
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    • 제30권3호
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    • pp.69-81
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    • 1988
  • The Repeated Load Triaxial and Oedometer Tests to the weathered granite & silty clay soil have been fulfilled to investigate their dynarnic characteristics. The results obtained are summarized as follows ; 1. In the relation between the repeated triaxial compression and the oedometer test, the recoverable strain of weathered granite soil showed a tendency to decrease by the increase of the repeated loads number(N), and that of silty clay showed approximately constant values while the total strain increased continuously. 2. The changes of plastic strain was dependent to the level of deviator stress which is the most important element in the calculation of soil deformation under repeated load condition. And there was a significance of 10% between the level of stress and plastic strain. 3. When the soil was aimost dried or saturated to 100%, the deformation by the repeated loads was small. However the deformation showed peak around the saturation of 50%. 4. When the deformation was predicted by the repeated triaxial load tests of a laboratory, it is desirable to introduce the threshold stress concept in the calculation of deformation of subgrade of the pavement. 5. The improved design equation (Eq. 16) introducing the modulus of conversion(Fo), which is based on the Boussineq' s theory, is considered to be rational in the design of flexible pavement. From the above results, the deformation to the repeated traffic loads could be predicted by the repeated triaxial tests on the pavement materials or undisturbed soil layers, therefore it is think that the durable and econornic pavement could be constructed by reflecting that to the design.

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지오그리드로 보강된 투수성 연성포장 보조기층제 영구변형을 고려한 층두께 산정 비교 연구 (Evaluation of Geogrid-Reinforced Subbase Layer Thickness of Permeable Flexible Pavements based on Permanent Deformation Model)

  • 권혁민;오정호;한신인
    • 한국도로학회논문집
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    • 제17권1호
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    • pp.69-75
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    • 2015
  • PURPOSES : The objective of this study is to evaluate the effectiveness of a geogrid reinforced subbase of permeable flexible pavement structures with respect to permanent deformation. METHODS : Experimental trials employing a repeated triaxial load test scheme were conducted for both a geogrid reinforced subbase material and a control specimen to obtain the permanent deformation properties based on the VESYS model. Along with this, a finite element-based numerical analysis was conducted to predict pavement performance with respect to the rutting model incorporated into the analysis. RESULTSAND CONCLUSIONS : The results of the experimental study reveal that the geogrid reinforcement seems to be effective in mitigating permanent deformation of the subbase material. The permanent deformation was mostly achieved in the early stages of loading and then rapidly reached equilibrium as the number of load applications increased. The ultimate permanent deformation due to the geogrid reinforcement was about 1.5 times less than that of the control specimen. Numerical analysis showed that the permeable, flexible pavement structure with the geogrid reinforced subbase also exhibits less development of rutting throughout the service life. This reduction in rutting led to a 20% decrease in thickness of the subbase layer, which might be beneficial to reduce construction costs unless the structural adequacy is not ensured. In the near future, further verification must be conducted, both experimentally and numerically, to support these findings.

Use of vibration characteristics to predict the axial deformation of columns

  • Moragaspitiya, H.N. Praveen;Thambiratnam, David P.;Perera, Nimal J.;Chan, Tommy H.T.
    • Structural Engineering and Mechanics
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    • 제50권1호
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    • pp.73-88
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    • 2014
  • Vibration characteristics of columns are influenced by their axial loads. Numerous methods have been developed to quantify axial load and deformation in individual columns based on their natural frequencies. However, these methods cannot be applied to columns in a structural framing system as the natural frequency is a global parameter of the entire framing system. This paper presents an innovative method to quantify axial deformations of columns in a structural framing system using its vibration characteristics, incorporating the influence of load tributary areas, boundary conditions and load migration among the columns.

이축인장압축장이론에 기반한 PSC보의 전단변형 (Shear Deformation based on the Biaxial Tension-Compression Theory in Prestressed Concrete Members applied by Axial Loading)

  • 정제평;김대중;모귀석;김우
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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    • pp.281-284
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    • 2006
  • ASCE-ACI Committee 426 and 445, on Shear and Torsion, well noted in their report that recent research work regarding shear and torsion had been devoted primarily to members. But it was not logical approach of PSC members applied by axial force based on the shear deformation in web element. And it was not included that the effect of axial is to shift the shear strain(or crack width) in the web element versus the applied shear curve up or down by the amount by which the biaxial tension-compression state varies. The shear strength also increases or decreases, so that the change in shear strain at service load due to the presence of axial load is to some extent changed. Generally, in corresponding beams the shear strain at service load is less in the beam subject to axial compression and greater in the beam subject to axial tension, than in the beam without axial load. In particular, however, no research were available on the shear deformation in shear of PSC members with web reinforcement, subject to axial force in addition to shear and bending. Therefore, this study was basically performed to develop the program for the calculation of the shear deformation based on the shear effect of axial force in prestressed concrete members.

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외부변형이 섬유보강콘크리트의 인성에 미치는 영향 (Influence of Extraneous Deformation on the Toughness of Fiber Reinforced Concrete)

  • 김경수;고영주;임정환;배주성
    • 한국구조물진단유지관리공학회 논문집
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    • 제4권1호
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    • pp.111-120
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    • 2000
  • This study discusses the issues related to the accuracy of deflection measurement in the testing of FRC. Some deflection methods may include large extraneous deformations. such as local crushing at the loading points, elastic and inelastic deformations of the loading fixture, etc. A faulty load-deflection curve will be obtained if an unstable deflection measuring system is used, and incorrect toughness evaluation can be reached on the basis of this faulty curve. In this paper, the discussion will focus on the effects of the deflection measuring system on both the measurement of the load-deflection response of FRC and the evaluation of FRC toughness. It is observed that ASTM toughness indices which is based on measuring deflection at first cracking is influenced significantly by extraneous deformation in deflection measurement. But extraneous deformation in deflection measurement result in negligible errors in toughness evaluation using JSCE and JCI definition. However, in order to evaluate toughness accuracy, it is desirable to use net load-deflection curve eliminated extraneous deformation.

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AI 원형 관의 2축 압축 변형특성에 미치는 압축속도의 영향 (The effect of compressive strain rate on biaxial compressive deformation characteristics of Al circular pipe)

  • 원시태;정현진;안희준;조황현;유종근
    • 한국금형공학회:학술대회논문집
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    • 한국금형공학회 2008년도 하계 학술대회
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    • pp.23-26
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    • 2008
  • In order to examine the deformation characteristics of Al circular pipe underthe biaxial compression, the horizontal biaxial compression die for the experiment was manufactured. From this, in the various compressive strain rate (1 mm/min. ${\sim}$ 400 mm/min.)conditions, the circular pipes, which were made by Al materials, were investigated based on the properties change of cross section area, punch load and deformation behavior. The tensile and compressive strains were evaluated from micro Vickers hardness tester. From these results, the punch load and deformation characteristic of Al circular pipes were highly changed in the compressive strain rate about 200 mm/min. The Al circular pipes had the tendency that the punch load decreased with increasing the compressive strain rate. In addition, following as the change of the shape and position of neutral axis due to the deformation proceeding of the circular pipe, the special point of the internal circular pipe at maximum load showed the maximum deformation strain and the maximum measured hardness value. The CAE (computer aided engineering) simulation using Deform-2D program was performed on the circular pipe in order to know and verify the exact compressive deformation behavior. From these results, the experimentally measured results were reasonably in good agreement with the simulation results.

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