竹材物理力学性能及“试验方法草案”研究报告之一──小试件含水量的控制,顺纹抗压含水量换算系教,顺纹抗压加荷速度,饱和吸水速度及线干缩体干缩系数的决定,纤维饱和点的商榷──

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The purpose of this investigation is to study certain problems relating to the “Tentative Specification of the Testing Methods of the Physical and Mechanical Properties of Bamboo (Phyllostachy Edulis)” drafted by the senior author, and also to study some principal properties of . bamboo. In this present paper, the effects of moisture content and loading speed on the related properties of bamboo are discussed. The conclusions are stated below: Ⅰ. It is suitable to use H2SO4 as a drying agent to control the moisture content of the specimen. The amount of moisture contained in a given specimen can be determined if the treating period and the concentration of H2SO4 are known. The relationship between them is shown in Fig. 1 and Fig. 2. Ⅱ. The relationship between the moisture content and the compressive strength parallel to the grain is approximately a logarithmic curve when W=4-20%. If W>20%, its influence on the compressive strength becomes negligible. Quantitative results are stated below: where Kc designates the coefficient of compressive strength corresponding to the moisture content W, (w) designates the compressive strength parallel to the grain corresponding to the moisture content W. Ⅲ. Statistical analysis indicates that the speed of loading within the range of 1000±25% kg/cm2./min. is suitable for the testing of the compressive strength parallel to the grain for small clear specimens. The testing procedure and the method of analysis used are also suitable for the other strength properties of bamboo. Ⅳ. The relationship between dimensional or volumetric shrinkage and the change of moisture content may be expressed as two straight lines on a semi-logarithmic plot at W=4-20% and W>20% respectively. Equations for the ratio of shrinkage and numerical values of the coefficients of shrinkage are given. Ⅴ. From a consideration of the relationship between moisture content and the compressive strength, also the relationship between moisture content and the ratio of dimensional and volumetric shrinkage, the authors suggest that, for the purpose of practical application, W= 15-25% be used as the range of variation of the fiber-saturation point, and that W=20% be used as the fiber-saturation point. The purpose of this investigation is to study certain problems relating to the “Tentative Specification of the Testing Methods of the Physical and Mechanical Properties of Bamboo (Phyllostachy Edulis)” drafted by the senior author, and also to study some principal properties of .单词. The conclusions are stated below: I. It is suitable to use H2SO4 as a drying agent to control the moisture content of the specimen The amount of moisture contained in a given specimen can be determined if the treating period and the concentration of H2SO4 are known. The relationship between them is shown in Fig. 1 and Fig. 2. II. The relationship between the moisture content and the Compressive strength parallel to the grain is approximately a logarithmic curve when W=4-20%. If W>20%, its influence on the compressive strength becomes negligible. Quantitative results are stat Ed below: where Kc designates the coefficient of compressive strength corresponding to the moisture content W, (w) designates the compressive strength parallel to the grain corresponding to the moisture content W. III. Statistical analysis indicates that the speed of loading within the range of 1000±25% kg/cm2./min. is suitable for the testing of the compressive strength parallel to the grain for small clear specimens. The testing procedure and the method of analysis used are also suitable for the other strength properties of bamboo. IV Equations for dimensional ratio shrinkage and numerical values Of the coefficients of shrinkage are given. V. From a consideration of the relationship between moisture content and the compressive strength, also the relationship between moisture content a Nd the ratio of dimensional and volumetric shrinkage, the authors suggest that, for the purpose of practical application, W= 15-25% be used as the range of variation of the fiber-saturation point, and that W=20% be used as the fiber -saturation point.
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