• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1144-1149
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• 1994

Damage caused in CFRP laminates by low energy impact of steel ball are investigated ultrasonically. Two types of laminated specimens having different stacking sequence are used as a target material. The effects of pre-bending on the behaviors of impact damage are specifically discussed. The initiation and progagation behaviors of delamination were largely dependent upon the bending rigidity of each specimen. Specimen C having higher bending rigidity produced larger delamination damage than the Specimen D having relatively low bending rigidity, however it was little for the Specimen C. Application of pre-bending increased the apparent bending rigidity of target during impacting, it produced delamination at lower impact energy level compared to the case of no preload.

• Textile Coloration and Finishing
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• v.12 no.2
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• pp.121-128
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• 2000

This study discussed the mechanical properties such as bending and shear of polyester fabric treated with a several weight reduction machine. With the increase in the rate of weight loss, the bending rigidity of the warp and weft of treated fabric decreased regardless of the weight reduction machine. At 6.5% weight loss, the bending rigidity of warp and weft yarn decreased to $0.035\;gfcm^2/cm$ and $0.017\;gfcm^2/cm$, respectively, and these values show 54% and 94% of their untreated warp and weft. At same rate of the weight loss, the bending rigidity of polyester fabric treated with C.D.R slightly higher than that of the tank type or liquor-flow type. On the other hand, below 6.5% weight loss, the shear rigidity of the warp and weft of the treated fabric rapidly decreased. But with the increase in the above 6.5% rate of weight loss, the decreasing tendency of the shear rigidity declined. At same rate of the weight loss, the shear rigidity of fabric treated with tank type nearly equal to the that of the liquor flow type. But at same rate of the weight loss, the shear rigidity of the fabric treated with C.D.R type higher than that of the tank or liquor-flow type.

• Fashion & Textile Research Journal
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• v.5 no.3
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• pp.273-282
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• 2003

Effect of fixation methods and relaxation treatment on the flame retardant(FR) and physical properties of MDPP/HMM treated cotton weft-knitted fabrics were studied. Combination of four different fixation methods - relaxation, swelling agent treatment, pad dry cure fixation, and wet fixation - were applied to flame retardant finish of cotton weft-knitted fabric with MDPP/HMM. As the results, 1. Swelling agent and wet fixation method helps FR agent penetrate the fiber efficiently. Interlock showed relatively higher values of LOI than single jersey. 2. Interlock showed relatively higher values of bending rigidity(B), shear rigidity(G) and coefficient of friction(MIU) than those of single jersey before and after flame resistant treatment. 3. An increase in internal volume of cotton fiber by relaxation treatment increased the bending rigidity(B), shear rigidity(G) and compressional energy(WC). 4. The cotton weft-knitted fabric treated wet fixation, which crossliked FR agent efficiently, showed higher bending rigidity, shear rigidity(G) and lower compressional energy(WC). Retention of swelling ability of cotton weft-knitted fabrics treated with MDPP/HMM, which increased the internal volume of cotton weft-knitted fabric, showed lower bending rigidity.

• Fibers and Polymers
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• v.2 no.3
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• pp.148-152
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• 2001

Cotton yarns were coated with a polymer solution to hold surface fibers to the yam body, which caused fiber-fly generation during knitting process. The physical property of the coated yarn, especially a bending rigidity was investigated in order to evaluate the performance of the coated yam during knitting. SEM images showing the surface condition of the coated yarn demonstrated that the thickness of a coating material increased as the concentration of the coating solution increased. The results of the bending rigidity measured using KES-FB2 system showed that the bending rigidity of the coated yam increased as the concentration of the coating solution increased. The results also revealed the possibility that yarn coated with a low amount of coating material should be employed for further research of reducing fiber-fly generation during knitting process.

• Journal of Welding and Joining
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• v.25 no.1
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• pp.37-41
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• 2007

The purpose of this study is to establish the predictive method of angular distortion of the double-sided multi-pass butt weldment achieve it, the behavior of angular distortion in the butt weldment were investigated using comprehensive finite element analyses and experiments. The angular distortion in the multi-pass butt weldment strongly depends on the welding heat input(Q) and the effective bending rigidity of the weld throat. The effective bending rigidity of the first welding pass on the backing side was defined as the function of dimensionless parameter(k) and a bending rigidity of bead-on-plate weldment. Based on the results, the predictive equation for angular distortion of multi-pass butt weldment was proposed and verified by experiments.

• Steel and Composite Structures
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• v.31 no.4
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• pp.329-340
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• 2019

An innovated type of the flat steel plate-lightweight aggregate concrete hollow composite slab was presented in this paper. This kind of the slab is composed of flat steel plate and the lightweight aggregate concrete slab, which were interfaced with a set of perfobond shear connectors (PBL shear connectors) with circular hollow structural sections (CHSS) and the shear stud connectors. Five specimens were tested under static monotonic loading. In the test, the influence of shear span/height ratios and arrangements of CHSS on bending capacity and flexural rigidity of the composite slabs were investigated. Based on the test results, the crack patterns, failure modes, the bending moment-curvature curves as well as the strains of the flat steel plate and the concrete were focused and analyzed. The test results showed that the flat steel plate was fully connected to the lightweight aggregate concrete slab and no obvious slippage was observed between the steel plate and the concrete, and the composite slabs performed well in terms of bending capacity, flexural rigidity and ductility. It was further shown that all of the specimens failed in bending failure mode regardless of the shear span/height ratios and the arrangement of CHSS. Moreover, the plane-section assumption was proved to be valid, and the calculated formulas for predicting the bending capacity and the flexural rigidity of the composite slabs were proposed on the basis of the experimental results.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.4
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• pp.443-451
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• 1994

The bending rigidity of yarn is derived in terms of physicil and mechanical characteristics of its constituent fibers and yarns structural parametrs. Theoretical analysis shows that the twist correcti on factor for the bending rigidity of yarn decreases with increase of the ratio of Young's m()dulus to the shear modulus of the constituent fibers. Also, the bending rigidity of yarn decreases as the surface helix angle of yarn increases.

• Structural Engineering and Mechanics
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• v.65 no.2
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• pp.141-154
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• 2018

In this study, the bend-buckling strength of the web in longitudinally stiffened plate girder was numerically investigated. The buckling strength of the reinforced web was evaluated through an eigenvalue analysis of the hypothetical model, in which the top and bottom junctions of the web to the flanges were assumed as simple support conditions. Major parameters in the analysis include asymmetrical cross-sectional property, aspect ratio of the web, stiffener locations, and bending rigidity of the stiffeners. The numerical results showed that current AASHTO LRFD specifications (2014) provides the buckling strength from considerably safe side to slightly unsafe side depending on the location of the stiffeners. A modified equation for buckling coefficients was proposed to solve the shortcomings. The bending rigidity requirements of longitudinal stiffeners stipulated in AASHTO were also investigated. It is desirable to increase the rigidity of the stiffeners when the aspect ratio is less than 1.0.

• Fashion & Textile Research Journal
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• v.21 no.5
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• pp.597-605
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• 2019

This paper examined the garment formability and appearance of perspiration absorption, fast dry, and breathable fabrics. The mechanical properties and seam pucker properties of these fabrics were measured and regression analysis was conducted between fabric structural parameters and their mechanical and seam pucker properties. The superior total appearance value (TAV) of fast dry knitted fabrics for sports-wear was achieved in fabrics with high extensibility and bending rigidity; consequently, it increased with increasing stitch density and tightness factor. The formability of the fast dry knitted fabric also improved with an increasing stitch density and tightness factor. The seam pucker was influenced by bending rigidity and a good seam pucker was exhibited in the fast dry knitted fabrics with low stitch density and tightness factor. However, the formability (F) of the breathable fabric improved by increasing extensibility and bending rigidity that decreased with an increasing cover factor and the thickness of the breathable fabric. In addition, seam pucker deteriorated with an increasing cover factor and the thickness of the breathable fabric, which was similar to the results of the formability predicted in fabric mechanical properties. A superior seam pucker was achieved in fabrics with high extensibility and low bending rigidity.

• Fashion & Textile Research Journal
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• v.17 no.2
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• pp.287-294
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• 2015

This study investigates the physical properties of Murata Vortex Spinning (MVS) blended yarn with yarn count(20's, 30's, 40's) and blend ratio(Polyester 100, Polyester70:Cotton30, Polyester50:Cotton50, Polyester30:Cotton70, and Polyester50:Tencel40:Cotton10). This study evaluated tenacity, elongation, bending rigidity, bending hysteresis, hairiness coefficient, irregularity and twist number. The structure of MVS blended yarn influenced stress, strain, bending rigidity, bending hysteresis and the hairiness coefficient of MVS blended yarn decreased as the yarn count increased. MVS blended yarn consists of core and sheath. The core of MVS blended yarn is composed of a parallel fiber with a wrapping fiber that covers thecore fiber. This special structure of the MVS blended yarn effects the physical properties of the yarn; in addition, the mechanical properties of the component fibers influenced the stress, strain, bending rigidity, bending hysteresis and hairiness coefficient of MVS blended yarn with the blend ratio. Polyester decreases and cotton increases resulted in decreased physical properties. A similar polyester content increased the tencel and physical properties. Appropriate physical properties and a variety of touch expression can be realized through a correct blend ratio.