CAJ | 학술논문

提出测试 I 型断裂韧度的一类新型试样，包括边裂纹平台圆环、边裂纹平台半圆环、边裂纹平台半圆盘，以及它们没有平台的情况，一共6种构型。采用有限元方法标定这一类边裂纹平台(半)圆环(盘)的量纲一化的应力强度因子，分析其变化规律，并给出相应的曲线拟合公式。结果显示，边裂纹(平台)圆环试样量纲一化的应力强度因子-裂纹长度曲线具有先升后降的特殊性质，这使得它们的测试临界点容易从对应的载荷-位移曲线判断和确定，可以方便地测试材料的断裂韧度。边裂纹平台半圆盘也有类似的性质，但试样宜选取较大的平台角，而边裂纹半圆盘和边裂纹(平台)半圆环却没有这种性质。此外，经过初步试验，用边裂纹平台半圆盘和边裂纹平台半圆环试样测得砂岩的断裂韧度，与用国际岩石力学学会建议试样所测结果吻合。
제출측시 I 형단렬인도적일류신형시양，포괄변렬문평태원배、변렬문평태반원배、변렬문평태반원반，이급타문몰유평태적정황，일공6충구형。채용유한원방법표정저일류변렬문평태(반)원배(반)적량강일화적응력강도인자，분석기변화규률，병급출상응적곡선의합공식。결과현시，변렬문(평태)원배시양량강일화적응력강도인자-렬문장도곡선구유선승후강적특수성질，저사득타문적측시림계점용역종대응적재하-위이곡선판단화학정，가이방편지측시재료적단렬인도。변렬문평태반원반야유유사적성질，단시양의선취교대적평태각，이변렬문반원반화변렬문(평태)반원배각몰유저충성질。차외，경과초보시험，용변렬문평태반원반화변렬문평태반원배시양측득사암적단렬인도，여용국제암석역학학회건의시양소측결과문합。
A series of new specimens were proposed for testing the toughness of mode I fractures:flattened ring with edge cracks,semicircular flattened ring with edge cracks,edge cracked semicircular flattened disc,and their counterparts without flattened ends. Finite element method was used to calibrate the dimensionless stress intensity factor of these specimens and analyse and curve fit the variation of the stress intensity factor. The results reveal that for the edge cracked(flattened) ring,the curve of dimensionless stress intensity factor versus dimensionless crack length appear to be ascending succeeded by descending;so the critical point can be identified directly from the corresponding load-displacement curve based on this unique property,bringing convenience for measuring the material′s fracture toughness. The edge cracked flattened semicircular disc also has such property,but wider flattened ends should be chosen. While the edge cracked semicircular disc and edge cracked(flattened) semicircular ring do not have this unique characteristics. In addition,in the preliminary experimental test,the fracture toughness of a sandstone determined with the edge cracked flattened semicircular disc and the edge cracked flattened semicircular ring coincides respectively with the results derived with the specimen suggested by the International Society for Rock Mechanics.