볼트결합 구조의 부재 강성 연구

정현수(Hyun Su Jung),한혜선(Hye Sun Han),조재욱(Jae Uk Jo),박성우(Sung Woo Park) 한국생산제조학회 2018 한국생산제조학회지 Vol.27 No.3

Bolt joints are applied especially in equipment with severe temperature change during the operating. A change in the initial axial force of the bolt due to the dissimilar material of the members causes the performance deterioration of the equipment. The variation in the bolt axial force is influenced by the member stiffness. Many have studied the method of calculating the member stiffness in a bolt–nut joint. The studies have shown the same result for calculating the member stiffness in bolt joints. Bolts of sizes M4 to M8, and the thickness and material of various members were considered in the case study. Through finite element analysis, the analytical solution of member stiffness is calculated. An equivalent pressure cone model is used to calculate the theoretical solution. The analytical result and theoretical solution were almost equal. Additionally, we proposed a formula to calculate the member stiffness relatively easily in various cases.

Experimental and theoretical behaviour analysis of steel suspension members subjected to tension and bending

Stanislav Kmet,Michal Tomko,Molinne Bin 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.4

Steel suspension members subjected to tension and bending offer an economical and efficient alternative for many structural problems. This paper is concerned with the elastic and elastic-plastic behaviour of suspension members with bending stiffness subjected to vertical point and uniformly distributed loads. An experimental study is described which focuses on the response of three suspension members with various Tshaped steel hot rolled sections and geometric configurations. The tests enable direct assessment of the influence of a key parameter such as the sag-to-span ratio on the response of suspension members. Detailed nonlinear finite-element models are generated to provide a tool for theoretical analyses and to facilitate further understanding of the behaviour. Results demonstrate that experimentally obtained responses can generally be closely predicted numerically because there are relatively good agreements between finite element and tests results. The results and observations of subsequent numerical parametric studies offer an insight into the key factors that govern the behaviour of suspension members with bending stiffness in the elastic-plastic range.

Mathematical representation of bolted-joint stiffness: A new suggested model

Nawras Haidar,Salwan Obeed and Mohamed Jawad 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.11

Joint member stiffness in a bolted connection directly influences the safety of a design in regard to both static and fatigue loading, as well as in the prevention of separation in the connection. This work provides a new simple model for computing the member stiffness in bolted connections for both fully and partially developed stress envelope fields. The new model is built using a stress distribution polynomial of third order. Finite element analysis (FEA) is performed for some joints geometries, and the results are used to estimate the best analytical envelope angle in the proposed analytical model that gives suitable convergence between the compared results. An experimental effort is exerted to validate the accuracy of a suggested model. When analytical results are compared with FEA results and experimental data, the maximum absolute percentage errors are found to be 2.69 and 14.69, respectively. Also, a good agreement is obtained when the analytical results are compared with other researchers’ results.

합성부재를 이용한 고층평면골조의 강성최적설계에 관한 연구

김호수,이한주 한국공간구조학회 2004 한국공간구조학회지 Vol.4 No.3

본 연구에서는 횡하중을 받는 합성부재를 이용한 고층평면골조의 횡변위를 정량적으로 제어할 수 있는 효율적인 강성최적설계기법을 제시하고자 한다. 이를 위해 합성부재를 이용한 고층 구조물의 거동특성을 고려한 민감도 해석을 수행하며, 아울러 수학적계획법의 일반성을 유지하면서도, 큰 규모의 문제도 효율적으로 다룰 수 있는 근사화 개념을 도입하여 구속조건식을 설정한다. 특히 초기에 주어진 단면형상이 최적설계 과정동안 계속 유지된다는 가정을 이용하여 최적설계결과에서 구해진 단면특성에 따라 합성부재의 치수를 산출하는 방안을 강구한다. 제시된 정량적인 횡변위 제어 방안의 효용성을 검토하기 위해 두 가지의 50층 골조 예제가 고려된다. This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift for tall frameworks using composit member subject to lateral loads. To this end, displacement sensitivity depending on behavior characteristics of tall frameworks is established and approximation concept that preserves the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Specifically, under the 'constant-shape' assumption, resizing techniqe of composite member is developed. Two types of 50 story frameworks are presented to illustrate the features of the quantitative lateral drift control technique proposed in this study.

알루미늄 저압중공주조 공법을 이용한 후륜 크로스멤버 개발

윤석진(Sukjin Yoon),손준형(Junhyung Sohn),장우정(Woojung Jang),윤주영(Juyoung Yoon),이용욱(Yonguk Lee),조영건(Younggun Cho) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11

In the case of a suspension part, since it is located in the lower part of the vehicle, it has a great advantage of improving fuel economy due to weight reduction. In order to reduce the weight of vehicles, there are increasing cases of applying aluminum to suspension parts. This paper describes the stages of development of a rear cross member with a welded aluminum low pressure hollow casting method and extrusion method. The result of the aluminum cross member study showed that the weight was reduced by 6.3㎏ and natural frequency was improved by 46.7㎐ compared with the steel cross member.

볼트결합 구조부의 조건에 따른 동적변화 해석

朴明均,朴世蔓 明知大學校 産業技術硏究所 2004 産業技術硏究所論文集 Vol.23 No.-

To join structures together, various methods and processes are available including welding, riveting, bonding with industrial adhesives and fastening by bolts. The structural factors affecting the dynamic behavior of the joined structures are usually believed to be materials composing the bolts, bolt sizes and the number of bolts as well as the strength of applied torque and the extent of overlap between the structures joined together. This paper analyzes the impacts of the structural factors such as the bolt sizes, the extent of overlap and the materials composing the structures on the dynamic behavior of the joined structures In this research an impulse hammer technique is applies to investigate the dynamic behavior of joints produced by bolts. The results have demonstrated that the resonance frequencies of the joints increase with the increasing torque and decreasing overlap length and stiffness.

구조 성능 증대를 위한 자동차 차체부품 비드 최적화

최원철(Woncheol Choi),김정섭(Jungsub Kim),정판근(Pankeun Jeong),천건희(Geonhee Cheon),홍종빈(Jongbin Hong) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11

The purpose of this study is that the optimal bead structure is apply for cowl cross member have steel material to increase the stiffness performance through the optimization analysis. Firstly, to determine the bead shape, modal and structural analysis of many bead shape types were carried out and the optimal bead shape was selected. Secondly, in order to analyze the influence of the design factors about selected bead shape, bead optimization analysis was carried out considering main effect of each design factors such as bead height and width. In addition, the bead shape has optimal design factors was applied in the stiffness weak areas of the conventional type. Finally, to check reliability about increase the stiffness performance, modal and structural analysis of cowl cross members were carried out and it was possible to check increase the stiffness performance and the same level of weight as the conventional type.

Nonlinear model to predict the torsional response of U-shaped thin-walled RC members

Shenggang Chen,Yinghua Ye,Quanquan Guo,Shaohong Cheng,Bo Diao 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.6

Based on Vlasov‟s torsional theory of open thin-walled members and the nonlinear constitutive relations of materials, a nonlinear analysis model to predict response of open thin-walled RC members subjected to pure torsion is proposed in the current study. The variation of the circulatory torsional stiffness and warping torsional stiffness over the entire loading process and the impact of warping shear deformation on the torsion-induced rotation of the member are considered in the formulation. The torque equilibrium differential equation is then solved by Runge-Kutta method. The proposed nonlinear model is then applied to predict the behavior of five U-shaped thin-walled RC members under pure torsion. Four of them were tested in an earlier experimental study by the authors and the testing data of the fifth one were reported in an existing literature. Results show that the analytical predictions based on the proposed model agree well with the experimental data of all five specimens. This clearly shows the validity of the proposed nonlinear model analyzing behavior of U-shaped thin-walled RC members under pure torsion.

Efficient Method to Include Joint Zones of Chord Members in Finite Element Model of Tubular Transmission Tower at Linear Elastic Stage

Haifeng Liu,Junke Han,Zhenmao Sun,Jingbo Yang,Fengli Yang,Xiyu Xu 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.4

To include the effects of the joint zones efficiently, firstly a chord member considering the joint zones is seen as a combination of three beams with different sections and its element stiffness matrix is derived; Secondly, based on the statistically geometrical properties of the joint zones and chord members in service, the coefficients in the element stiffness matrix of the varied section beam element related to the moments and shear forces greatly increase more than 70%, while the coefficients related to axial forces only increase less than 2%. Therefore, along with the other two inherent mechanical properties of member structures, it is essential to include the effects of the joint zones. Finally, the results by the finite element models where the chord members and the joint zones are simulated by four methods are compared, which proves the efficiency and the accuracy of the varied section beam element.

강성도 기준에 따른 IsoTruss<SUP>®</SUP> 그리드 고층건물의 부재선정 방법

김태헌(Tae-Heon Kim),김영찬(Young-Chan Kim) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.12

고층건물에서 횡력 저항의 주된 역할을 하는 외주골조는 기둥과 보를 직교시켜 구성하는 것이 일반적이었으나 최근 다양한 그리드형태의 부재배치가 이루어지고 있다. 선행연구에서는 아이소트러스 그리드를 고층건물의 외주골조로 적용한 구조적 적합성이 검토되었다. 본 연구에서는 IsoTruss<SUP>®</SUP> 그리드(ITG) 구조의 예비단계 설계시 외주골조 부재의 소요단면적 산정방법을 제안하였다. 모듈의 변형과 하중과의 평형조건, 허용 횡변위, 그리고 건물의 휨변형 대 전단변형의 비를 변수로하여 소요단면적을 유도하였다. ITG 구조에서 외주골조의 부재는 횡하중에 직각인 평면(PPR), 평행한 평면(PPL), 경사진 평면(POQ)에 배치되는데 POQ에 배치된 부재는 PPR 또는 PPL에 투영시켜 부재의 강성을 반영하였다. 소요단면적은 모듈에 작용하는 전단력과 모멘트에 의해 영향을 받는데 부재사이즈 조닝을 달리하여 3가지 모델을 비교하였다. 본 연구의 효용성을 검증하기 위해 64층 건물을 설계하여 해석하였다. 최대 횡변위, 철골량, 기둥의 축력강도비를 비교분석하여 부재사이즈 조닝 의 효과를 알아보았다. 제안식을 이용한 횡변위가 제한치의 약 97.3%로 나와 제안식을 설계 초기단계에서 부재사이즈의 선정에 유용하게 적용할 수 있다. The perimeter structure in high-rise buildings, which plays a major role in resisting lateral forces, is generally formed by the orthogonal placement of the beam and column, but currently various grid patterns are implemented. In a previous study, the adaptability of the IsoTruss<SUP>®</SUP> grid (ITG) as a perimeter structure was examined. In this study, a method of estimating the required cross sectional area of a member in a preliminary design is proposed. The members of the perimeter structure are placed in three planes, perpendicular (PPR), parallel (PPL) and oblique (POQ) to the lateral loading, and the stiffness of the members in the POQ was taken into account by projecting them onto the PPL or PPR. Three models are established for member size zoning through the height of the building, in order to investigate the effect of the shear and moment in the calculation of the required cross sectional area. To examine the effectiveness of this study, a 64-story building is designed and analyzed. The effect of the member size zoning was examined by comparing the maximum lateral displacement, required steel amount, and axial strength ratio of the columns. Judging from the maximum lateral displacement, which was 97.3% of the allowable limit, the proposed formula seems to be implemental in sizing the members of an ITG structure at the initial stage of member selection.