• Title, Summary, Keyword: crack filler

Search Result 43, Processing Time 0.033 seconds

Fatigue behavior of mechanical structures welded with different filler metal

  • Alioua, Abdelkader;Bouchouicha, Benattou;Zemri, Mokhtar;IMAD, Abdellatif
    • Advances in materials Research
    • /
    • v.6 no.3
    • /
    • pp.233-243
    • /
    • 2017
  • This paper describes an investigation on the effect of using three different filler metals on fatigue behavior of mechanical structures welded. The welding is carried out on the steel A510AP used for the manufacture of gas cisterns and pipes. The welding process used is manual welding with coated electrodes and automatic arc welding. Compact tension CT50 specimen has been used. The three zones of welded joint; filler metal FM, heat affected zone HAZ and base metal BM have been investigated. The results show that the crack growth rate CGR is decreasing respectively in BM, FM and HAZ; however, this variation decreases when stress intensity factor SIF increases. For low values of SIF, the CGR is inferior in the over-matched filler metal of which the value of mismatch M is near unity, but for high values of M the CGR is superior, and the effect of the over-matching on CGR becomes negative. No deviation of the crack growth path has been noticed.

Fracture Toughness of IC Molding Compound Materials(II) (IC 몰딩 콤파운드 재료의 파괴 인성치(II))

  • 김경섭;신영의
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.11 no.5
    • /
    • pp.353-357
    • /
    • 1998
  • Cracking problem of Epoxy Molding Compound(EMC) is critical for the reliability of the plastic package during temperature cycling and IR-reflow condition. Fracture toughness of EMC, which is defined as the resistance of EMC to the crack propagation, is a useful factor in ht estimation of EMC against package crack. Thus, development of EMC having high fracture toughness at a given loading condition would be important for confirming the integrity of package. In this study, toughness of several EMC was measured by varying the test conditions such as temperature, loading speeds, and weight percent of filler in order to quantify the variation of toughness of EMC under various applicable conditions. It was found from the experiments that toughness of all EMC has following trends, i.e., it rapidly decreases over the glass transition temperature, remains almost same or little decreases below $0^{\circ}C$. It decreases with the growth of cross head speed in EMC and the weight percent of filler as the degree of brittleness of EMC increases with the amount of filler content.

  • PDF

Thermal Characteristic of the Tubular Single tap Adhesively Bonded Joint bonded with filler containing epoxy adhesive (충전재가 함유된 단일겹치기 접착 조인트의 열적 특성에 관한 연구)

  • Kim, Jin-Kook;Lee, Dai-Gil
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.370-376
    • /
    • 2001
  • When an adhesive joint is exposed to high environmental temperature, the tensile load capability of the adhesive joint decreases because the elastic modulus and failure strength of structural adhesive decrease. The thermo-mechanical properties of structural adhesive can be improved by addition of fillers to the adhesive. In this paper, the elastic modulus and failure strength of adhesives as well as the tensile load capability of tubular single lap adhesive joints were experimentally and theoretically investigated with respect to the volume fraction of filler (alumina) and the environmental temperature. Also the tensile modulus of the fille containing epoxy adhesive was predicted using a new equation which considers filler shape, filler content and environmental temperature. The tensile load capability of the adhesive joint was predicted by using the effective strain obtained from the finite element analysis and a new failure model, from which the relation between the bonding length and the crack length was developed with respect to the volume fraction of filler.

  • PDF

Effect of Al2O3 Filler Addition on Sintering Behavior and Physical Characteristics of BaO-B2O3-ZnO Glass Ceramic System (BaO-B2O3-ZnO 결정화 유리계에서 Al2O3 Filler의 첨가에 따른 소결거동 및 물성변화)

  • Kim, Byung-Sook;Kim, Young-Nam;Lim, Eun-Sub;Lee, Joon-Hyung;Kim, Jeong-Joo
    • Journal of the Korean Ceramic Society
    • /
    • v.42 no.2
    • /
    • pp.110-116
    • /
    • 2005
  • Suitable compositions which are sinterable at low temperature in the $BaO-B_{2}O_{3}-ZnO$ glass system were investigated as a function of the ratio between BaO and ZnO. The effect of $Al_{2}O_3$ filler on densification and physical characteristics of the glass was also examined. When the amount of $Al_{2}O_3$ filler increased, the densification rate and the values of dielectric constant, thermal expansion coefficient and hardness in the glass-filler composites decreased gradually. The decreasing rate of the physical properties accelerated when fine $Al_{2}O_3$ filler was used. However, the fracture toughness of the composite rather increased due to the existence of filler particles and pores which effectively suppressed crack propagation with addition of fine $Al_{2}O_3$ filler.

Crack and Cutting Resistance Properties of Natural Rubber(NR) Compounds with Silica/Carbon Black Dual Phase Filler (Silica/Carbon Black이 충전된 NR 가황물의 내Crack 및 내Cutting 특성)

  • Son, Woo-Jung;Cho, Ur-Ryung;Kim, Won-Ho
    • Elastomers and Composites
    • /
    • v.37 no.2
    • /
    • pp.86-98
    • /
    • 2002
  • The application of silica/carbon black dual phase fillers to natural rubber(NR) compound was investigated. When the amounts of filler content were restricted to 60phr, the optimum ratio of dual phase fillers were 25phr/35phr of silica/carbon black. It was found that these new fillers give better overall performance in comparison with carbon black in tear strength, crack resistance, and cutting resistance. Also the thermal degradation resistance of NR vulcanizates which were filled with dual phase fillers was better than that of the carbon black. Dual phase fillers filled NR vulcanizates showed better viscoelastic properties, like tan${\delta}$, for the wet skid resistance and rolling resistance of motor vehicle tires.

Flexural analysis of transverse joints of prefabricated T-girder bridge superstructure

  • Kye, Seungkyung;Jung, Hyung-Jo;Park, Sun-Kyu
    • Structural Engineering and Mechanics
    • /
    • v.77 no.1
    • /
    • pp.89-102
    • /
    • 2021
  • Rapid construction of prefabricated bridges requires minimizing the field work of precast members and ensuring structural stability and constructability. In this study, we conducted experimental and analytical investigations of transverse joints of prefabricated T-girder bridge superstructures to verify the flexural performance and serviceability. In addition, we conducted parametric studies to identify the joint parameters. The results showed that both the segmented and continuous specimens satisfied the ultimate flexural strength criterion, and the segmented specimen exhibited unified behavior, with the flexural strength corresponding to that of the continuous specimen. The segmented specimens exhibited elastic behavior under service load conditions, and the maximum crack width satisfied the acceptance criteria. The reliability of the finite element model of the joint was verified, and parametric analysis of the convexity of the joint section and the compressive strength of the filler concrete showed that the minimum deflection and crack width occurred at a specific angle. As the strength of the filler concrete increased, the deflection and crack width decreased. However, we confirmed that the reduction in the crack width was hardly observed above a specific strength. Therefore, a design suitable for prefabricated bridges and accelerated construction can be achieved by improving the joint specifications based on the required criteria.

SOLIDIFICATION CRACKING SUSCEPTIBILITY OF

  • Yoon, Jong-Won
    • Proceedings of the KWS Conference
    • /
    • /
    • pp.577-582
    • /
    • 2002
  • The solidification cracking susceptibilities of AI-Mg-Si alloy laser welds were assessed using the self-restraint tapered specimen crack test. The cracking susceptibility of 6061 and 6082 Al-Mg-Si alloy laser welds was substantially reduced when the filler wire containing high Si such as Al-12 wt.% Si (4047A) was used. The amount of eutectic was observed to affect the solidification cracking of Al-Mg-Si alloy laser welds. Abundant eutectic seems to heal the cracking and reduces the cracking susceptibility, while an initial increase in eutectic liquid leads to the increased cracking tendency.

  • PDF

Effects of Brazing Current on Mechanical Properties of Gas Metal Arc Brazed Joint of 1000MPa Grade DP Steels (1000MPa급 DP강 MIG 아크 브레이징 접합부의 기계적 성질에 미치는 브레이징 전류의 영향)

  • Cho, Wook-Je;Yoon, Tae-Jin;Kwak, Sung-Yun;Lee, Jae-Hyeong;Kang, Chung-Yun
    • Journal of Welding and Joining
    • /
    • v.35 no.2
    • /
    • pp.23-29
    • /
    • 2017
  • Mechanical properties and hardness distributions in arc brazed joints of Dual phase steel using Cu-Al insert metal were investigated. The maximum tensile shear load was 10.4kN at the highest brazing current. It was about 54% compared to tensile load of base metal. This joint efficiency is higher than that of joint of DP steel using Cu-based filler metals which are Cu-Si, Cu-Sn. Fracture positions can be divided into two types. Crack initiation commonly occurred at three point junction among upper sheet, lower sheet and the fusion zone. However crack propagations were different with increasing the brazing current. In case of the lower current, it instantaneously propagated along with the interface between fusion zone and upper base material. On the other hand, in case of higher current, a crack propagation occurred through fusion zone. When the brazing current is low (60, 70A), the interface shape is flat type. However the interface shape is rough type, when the brazing current is high (80A). It is thought that the interface shapes were the reason why the crack propagations were different with brazing current. The interface was the intermetallic compounds which consisted of $(Fe,Al)_{0.85}Cu_{0.15}$ IMC formed by crystallization at $1200^{\circ}C$during cooling. Therefore the maximum tensile shear load and the fracture behavior were determined by a interface shape and effective sheet thickness of the fracture position.

Analysis of Crack Behavior of dissimilar materials in Brazed Interface By BEM (이종재 브레이징 계면에서의 균열거동해석)

  • 오환섭;김시현;김성재
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • /
    • pp.269-274
    • /
    • 2001
  • Applications of Brazing in the studying fields such as High-Speed Machining are very increasing in various industry fields. Therefore, Applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem Dissimilar Materials in Brazed Interface. In this study, Stress intensity Factor (S.I.F) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a Hardmetal and a HSS by two dimensional(2-D) Boundary Element Method (BEM). Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine Stress Intensity Factor.

  • PDF

Analysis of Crack Behavior of Brazed Interface in Dissimilar Materials using BEM (이종재 브레이징 계면에서의 균열거동 해석)

  • 오환섭;김시현;김성재;양인수
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.11 no.6
    • /
    • pp.91-97
    • /
    • 2002
  • Applications of brazing in the studying fields such as high-speed machining are very increasing in various industry fields. Therefore, applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem dissimilar materials in brazed interface. In this study, stress intensity factor(SIF) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a hardmetal and a HSS by two dimensional(2-D) BEM. Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine SIF.