高频真空干燥中压缩载荷对落叶松长方形髓心方材表面裂纹的影响

Effect of Compressive Loading on the Surface Check on Larch Boxed Heart Rectangular Timber during Radio-frequency/Vacuum Drying

探究了高频真空干燥中压缩载荷对有纵向槽的落叶松长方形髓心方材表面裂纹的影响。研究结果如下:与正方形方材相比,由于压缩载荷作用和长方形方材宽度的增加,长方形方材宽度与厚度干缩率比大大减少了;因为高频加热和干缩差异应力的减少,长方形方材表面裂纹减少了许多,尤其没有纵向槽的长方形方材表面裂纹明显减少。

This study was conducted to explore the effect of compressive loading on the surface check on Japanese larch boxed heart rectangular timbers during radio-frequency/vacuum drying.The results of this study were as follows： the ratio of the width shrinkage to the thickness shrinkage of the rectangular timbers was significantly decreased compared to that of the square timbers due to increasement of applied compressive load caused by increased width of rectangular timber;the surface checks on the rectangular timbers were considerably decreased compared to those on the square timbers,especially the checks on the unkerfed rectangular timbers were remarkably decreased because of the reduced differential shrinkage stresses and dielectric heating.