• Title/Summary/Keyword: Maximum Strength

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Holding Strength of Screws in Domestic Particleboard and Medium Density Fiberboard (I) - Optimum Pilot Hole Diameter - (국산 파티클보오드와 중밀도 섬유판의 나사못 유지력(I) - 최적 예비구멍 직경 -)

  • Lee, Phil-Woo;Park, Hee-Jun;Han, Yu-Soo
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.3
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    • pp.27-34
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    • 1991
  • Screw withdrawal test was carried out on the face and edge of domestic particleboard and medium density fiberboard in order to evaluate optimum pilot hole diameter. The obtained results were as follows: 1. Maximum withdrawal strengths on the face and edge of particleboard were obtained with pilot hole diameters at about 50% of root diameters of screw. 2. Maximum withdrawal strength on the face and edge of medium density fiberboard were obtained with pilot hole diameters that were about 60% and 50% of root diameters of screw, respectively. 3. Withdrawal strength showed about 91% of maximum withdrawal strength when pilot holes were not pre bored at particleboard. but when pilot holes at 90% of root diameter of screw withdrawal strength showed about as 51.3% of maximum withdrawal strength. 4. Withdrawal strength showed about 88% of maximum strength when pilot holes were not used, but withdrawal strength indicated 55.4% of maximum strength in case of 90% of root diameters of screw. 5. Maximum withdrawal strength on the face of particleboard was about 70.5% higher than that of the edge, and however medium density fiberboard was about 19.6% higher than that of the edge.

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The Relation of Bending Buckling Strength in Vehicle and Three Point Bending Maximum Strength of Door Impact Beam (도어 임팩트 빔의 3점 굽힘 최대강도와 차량 장착 시 굽힘 좌굴강도와의 관계)

  • Kang, Sungjong;Lee, Sangmin
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.1
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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.

Long-Term Performance of High Strength Concrete

  • Choi Yeol;Kang Moon-Myung
    • Journal of the Korea Concrete Institute
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    • v.16 no.3 s.81
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    • pp.425-431
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    • 2004
  • This paper describes an experimental investigation of how time-dependent deformations of high strength concretes are affected by maximum size of coarse aggregate, curing time, and relatively low sustained stress level. A set of high strength concrete mixes, mainly containing two different maximum sizes of coarse aggregate, have been used to investigate drying shrinkage and creep strain of high strength concrete for 7 and 28-day moist cured cylinder specimens. Based upon one-year experimental results, drying shrinkage of high strength concrete was significantly affected by the maximum size of coarse aggregate at early age, and become gradually decreased at late age. The larger the maximum size of coarse aggregate in high strength concrete shows the lower the creep strain. The prediction equations for drying shrinkage and creep coefficient were developed on the basis of the experimental results, and compared with existing prediction models.

Comparison of Maximum Isometric Strength, Proprioceptive, Dynamic Balance, and Maximum Angle by Applying the Fascial Distortion Model to Chronic Ankle Instability Subjects

  • Lee, Jae Kwang;Kim, Chan Myeong
    • The Journal of Korean Physical Therapy
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    • v.33 no.5
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    • pp.224-230
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    • 2021
  • Purpose: The purpose of this study was to investigate the effects of the fascia distortion model (FDM), one of the fascia treatments, on unstable ankle subjects. This was done through the chronic ankle instability tool (CAIT) questionnaire on maximum isometric muscle strength, proprioception, dynamic balance, and maximum angle. Methods: An experiment was conducted using the chronic ankle instability tool questionnaire on males and females in their twenties who suffered from ankle instability. Before the experiment, maximum isometric strength, proprioceptive, dynamic balance, and maximum angle were measured. The fascia distortion model was applied and then measurements were taken again to compare and analyze the changes. Analysis was carried out using the paired t-test. Results: After applying the fascia distortion model, maximum isometric strength, proprioceptive, dynamic balance, and maximum angle significantly improved (p<0.05). Conclusion: This study found that the fascia distortion model method was effective in improving maximum isometric strength, proprioceptive, dynamic balance, and maximum angle. The results suggest that the fascia distortion model method is a new intervention that could be used for subjects with chronic ankle instability.

A Study on the Influence of Aggregate on the Estimation of Compressive Strength by Small Size Core (소구경 코어에 의한 콘크리트 압축강도 추정에 미치는 골재의 영향에 관한 연구)

  • 김경민;백병훈;한민철;윤기원;한천구;송성진
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2002.11a
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    • pp.51-54
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    • 2002
  • This study is intended to investigate an influence of the kinds and the maximum size of aggregate on the compressive strength of small size core specimen. According to the results, the compressive strength of standard specimen is large in order of basalt, granite and limestone aggregate, and shows increasing tendency as the maximum size of aggregate grows large. The compressive strength of concrete using basalt aggregate shows similar tendency to granite aggregate, and that of concrete using limestone aggregate decreases slightly, compared with granite aggregate. The reducing ratio of the compressive strength of 25mm core specimen is least when the maximum size of aggregate is 10mm. But the compressive strength of 50 and 100mm core specimen is almost not influenced by the maximum size of aggregate.

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Studies on Fracture Toughness in Internal Bond and Tension of Particleboard (파티클보드의 박리(剝離) 및 인장(引張)에 있어서의 파괴인성치(破壞靭性値)에 관(關)한 연구(硏究))

  • Kim, Han-Seok;Lee, Phil-Woo
    • Journal of the Korean Wood Science and Technology
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    • v.18 no.3
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    • pp.6-16
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    • 1990
  • The objectives of this study were to investigate the relative effects of specific gravity and particle size on internal bond and tensile strengths and fracture toughness of particleboard and to compare mechanical strength with fracture toughness. The particleboard was manufactured with three different particle sizes at specific gravity levels of 0.6, 0.7, and 0.8 with a resin content of 10% based on oven dry weight. The results were summarized as follows: 1. Internal bond strength. fracture toughness in internal bond test. maximum tensile strength, and fracture toughness in tension test increased with the increase of specific gravity of particleboard. 2. As partcle size increased, internal bond strength, fracture toughness. maximum tensile strength. and fracture toughness in tension test increased. 3. The maximum tensile strength and fracture toughness appeared to be in a direct relationship, and then maximum tensile strength could be used for predicition of fracture toughness for tension test. 4. The fracture toughness in internal bond test was somewhat independent on induced crack length.

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Effects of the Curing Temperature on the Strength of Mortar added Admixtures (양생온도(養生溫度)가 혼화재(混和材)를 사용(使用)한 Mortar의 강도(强度)에 미치는 영향(影響))

  • Kang, Sin-Up;Kim, Seong-Wan
    • Korean Journal of Agricultural Science
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    • v.3 no.2
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    • pp.214-224
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    • 1976
  • This research was attempted as one of studies on the strength of mortar added admixtures at different curing temperatures. Variations of curing temperature to. test compressive strength, tensil strength and bending strength were $20^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$ and these results were summarized as follow : In strength of mortar added briquette ash, the compressive strength was increased: 1.58 percent, the tensile strength 0.96 percent, and the bending strength 1.26 percent compared with standard strength, by increasing one degree of celsius temperature. Also in strength of mortar added fly ash, the compressive strength increased on the average 1.3 percent, the tensile strength 0.99 percent, and the bending strength 1.18 percent at the above conditions. In case of using fly ash as admixture, maximum compressive strengths was attained at the level of 25 percent of fly ash, maximum tensile strength at the level of 20 percent of fly ash, and maximum bending strength at the level of 20 percent of fly ash. In case of using briquette ash, maximum compressive strength was attained maximum strength at 20 percent of the admixture, maximum tensile strength at the level of 15 to 20 percent of admixture and maximum bending strength at the level of 20 percent of admixture. Although addition of briquette ash was less effective in increasing the strength compared with the addition of fly ash, briquette ash might be used as one of admixtures because the control of curing temperature might affect in getting the required practical strength.

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The Effects of Starch as a Retarder in Soil Cement Mixtures (지연제로서 전분이 시멘트혼합토에 미치는 영향)

  • 김재영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.18 no.3
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    • pp.4163-4170
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    • 1976
  • This study was conducted to investigate the effect of starch as a retarder on the maximum dry density and the unconfined compressive strength of soil cement mixtures for varied starch contents (0-3%), cement contents (3-12%), and delay times (0-6hrs) in four soils. The experimental results obtained from maximum dry density and unconfined compressive strength tests are as follows: 1. Maximum dry density and unconfined compressive strength were increased greatly in soil cement mixtues rwhen starch was added as retarder but their value schanged according to soil varieties. 2. Maximum dry density showed at about 0.5 percent to 1.0 percent of starch in KY soil and about 2.0 percent to 2.5 percent in SS soil when delay time was changed in 2.4, and 6 hours in compaction test. 3. The larger content of cement was, the bigger effects of maximum dry density and compressive strength were in soil cement. mixtures. 4. As delay time changed 2.4, and 6 hours in compaction test, 7-day unconfined compressive strength showed the biggest value at about 0.5 percent of starch in KY soil and 2.0 percent in SS soil, and the maximum value of 28-day unconfined compressive strength showed at about 0.5 percent in KY soil and 1.5 percent in SS soil.

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Fatigue Strength Evaluation of the Clinch Joints of a Cold Rolled Steel Sheet

  • Kim, Ho-Kyung
    • International Journal of Railway
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    • v.2 no.4
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    • pp.131-138
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    • 2009
  • Static tensile and fatigue tests were conducted using tensile-shear specimens to evaluate the fatigue strength of a SPCC sheet clinch joint. The maximum tensile strength of the specimen produced at the optimal punching force was 1750 kN. The fatigue endurance limit (=760 N) approached 43% of the maximum tensile load (=1750 N) at a load ratio of 0.1, suggesting that the fatigue limit is approximately half of the value of the maximum tensile strength. The FEM analysis showed that at the fatigue endurance limit, the maximum von-Mises stress of 373 MPa is very close to the ultimate tensile strength of the SPCC sheet (=382 MPa).

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A Study of Maximum Voluntary Strength Evaluation for Korean Workers (한국근로자의 임의적 최대근력 평가를 위한 연구)

  • Chung, Min-Keun;Kee, Do-Hyung;Kim, Tae-Bok
    • Journal of Korean Institute of Industrial Engineers
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    • v.18 no.1
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    • pp.141-153
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    • 1992
  • In order to evaluate task loads required by a majority of manual materials handling(MMH) jobs, we have performed the assessment of arm strength, leg strength and torso strength for Korean workers in a scientific and systematic manner. Two hundred and eighty five employees from two local manufacturing plants in Pohang participated in this project. Maximum voluntary strengths were assessed for the aforementioned three postures, and these data were classified by gender. These strength data were also used to generate a strength predicition model, which can estimate the maximum voluntary strength for a population with specific age, height and weight. These strength data will be used for the prevention of occupational injuries which are frequently incurred by overexertion in manual materials handling jobs.

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