This paper describes results and analysis of experimental testing of entire and partial compression strength and stiffness parallel to the grain of solid timber (Japanese cedar). To investigate the spreading effects, the size effect of strength and stiffness, and the mechanism of the damage zone located close to the loading plates, tests on 90 specimens were performed. As a result, it was observed that damage zones existed near the loading plates. The observed spreading effects in the compression parallel to the grain were very small which justifies neglecting them regarding strength and stiffness. Although a presence of a size effect of the compression strength parallel to the grain of glulam specimens with knots was reported, the compression strength parallel to the grain of solid wood specimens without knots does not have a size effect. The height and width of the cross-section of the specimens have an influence on the damage zones and, hence, on the effective modulus of elasticity of the full height of the specimens. The compression strength has a correlation with the density of the timber and the width of the annual rings.

中文翻译：

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平行于实木纹理的局部压缩试验研究

本文介绍了与实木（日本雪松）木材平行的全部和部分压缩强度和刚度的实验测试结果和分析。为了研究铺展效应，强度和刚度的尺寸效应以及损伤区域靠近加载板的机理，对90个试样进行了测试。结果，观察到在加载板附近存在损坏区域。在平行于晶粒的压缩中观察到的扩散效应非常小，这有理由忽略了它们的强度和刚度。虽然据报道存在平行于带结的胶合木样本的抗压强度的尺寸效应，但是平行于不具有结的实木试样的抗压强度的尺寸效应没有尺寸效应。样品横截面的高度和宽度会影响损坏区域，从而影响样品整个高度的有效弹性模量。抗压强度与木材的密度和年轮的宽度相关。