CAJ | 학술논문

建立了4组不同孔隙分布形式的多孔材料模型，在考虑孔隙分布范围和密度的基础上计算其孔隙分布分形维数，并利用假三维数值试验的方法获得了相同初始强度、不同孔隙度和孔隙分布形式试样的抗压强度。数值试验结果表明，除了孔隙度较小和孔隙分布分维数较大的试样破坏形式基本满足45°+j/2破裂角的规律以外，该分维数较小的试样均呈现出不对称的斜截面破坏；在孔隙度相同的情况下，该分维数越大，样品的抗压强度越高；通过推导假三维情况下材料孔隙度与抗压强度的理论关系发现，该分维数越大，样组的抗压强度随孔隙度增大而衰减的速率越慢；根据损伤力学模型对试样的抗压强度进行预测分析发现，当样组的该分维数较大时，该模型能够较准确地预测多孔材料的抗压强度，而当样组的该分维数逐渐减小时，损伤力学模型的精度也逐渐降低。上述规律是由孔隙分布分维数越小、孔隙分布越不均匀、试样中应力集中的累积效应越显著的原因而造成的。
건립료4조불동공극분포형식적다공재료모형，재고필공극분포범위화밀도적기출상계산기공극분포분형유수，병이용가삼유수치시험적방법획득료상동초시강도、불동공극도화공극분포형식시양적항압강도。수치시험결과표명，제료공극도교소화공극분포분유수교대적시양파배형식기본만족45°+j/2파렬각적규률이외，해분유수교소적시양균정현출불대칭적사절면파배；재공극도상동적정황하，해분유수월대，양품적항압강도월고；통과추도가삼유정황하재료공극도여항압강도적이론관계발현，해분유수월대，양조적항압강도수공극도증대이쇠감적속솔월만；근거손상역학모형대시양적항압강도진행예측분석발현，당양조적해분유수교대시，해모형능구교준학지예측다공재료적항압강도，이당양조적해분유수축점감소시，손상역학모형적정도야축점강저。상술규률시유공극분포분유수월소、공극분포월불균균、시양중응력집중적루적효응월현저적원인이조성적。
Four types of porous material models with different pore distribution patterns are established, and their fractal dimensions of pore distribution (FDPD) are calculated based on both the range and concentration of their pore locations. Then biaxial numerical experiments are conducted to obtain the compressive strength of samples with identical intact strength and different pore distributions and porosities. The results indicate that the failure modes of samples with small porosity or high FDPD conform to the law of 45°+j/2 angle of rupture, while other samples with low FDPD show asymmetric rupture in oblique section; for samples with identical porosity, the higher the FDPD is, the greater the compressive strength is; the theoretical relationship between sample porosity and its compressive strength proposed demonstrates that the higher the FDPD is, the slower the rate of strength declining with the growth of porosity is;and according to the prediction for compressive strength using damage model, the predicting result is more accurate for porous materials when their FDPD is high, while its accuracy gradually decreases as the FDPD becomes lower. The laws above can be attribute to the fact that a drop in FDPD will lead to more irregular distribution of pores, thus the accumulation of stress concentration in turn will more likely to trigger irregular and easy failures.