Fracture toughness (K_Q) testing with a mini‐compact tension (CT) specimen

Abstract

A testing method using the Rheometrics Mechanical Spectrometer as the loading instrument to measure the fracture toughness Ku, which is related to a specific sample geometry and dimensions (half-inch compact tension) is reported. The small sample size requirement makes it attractive to do fracture toughness testing on newly synthesized material for preliminary material study and comparison purposes. Commercially available epoxy resins were used to check the procedure at different temperatures (-150" to 250OC). An empirical crack length averaging method was used that appears to give constant Ku values independent of the a/W ratio values. The fracture surfaces were studied using scanning electron micros-COPY,

Geometrieunabhängige bruchmechanische Werkstoffkenngrößen - Voraussetzung für die Zähigkeitscharakterisierung von Kunststoffen

“…9a). Vergleich von K Qc -Werten an Mini-und Norm-CT-Pru Èfko Èrpern [36] (a); U È berpru Èfung der Unabha Èngigkeit der K Qc -Werte vom a/W-Verha Èltnis, ermittelt an Mini-CT-Pru Èfko Èrpern [36,37], an Hand der fu Èr Kunststoffe verallgemeinerten b (K)-Abha Èngigkeit (b) Fig. Zur U È berpru Èfung der Geometrieunabha Èngigkeit wurde die in Abb.…”

“…Zur U È berpru Èfung der Geometrieunabha Èngigkeit wurde die in Abb. Comparison of K Qc -values of miniaturized and standard CT-specimens [36] (a); verification of the independence of the K Qc -values measured by using miniaturized CT-specimens [36,37], from the a/W-ratio by means of the polymer-specific b (K)correlation (b) oberhalb des Streubereiches von b (K) sind dementsprechend geometrieunabha Èngig, d. h. die Mini-CT-Pru Èfko Èrper aus den Werkstoffen in Abb. Mit Hilfe dieses Zusammenhanges ko Ènnen unter Einbeziehung des Streubereiches rechnerisch (Gl.…”

Fatigue crack propagation experiment and numerical simulation of 42CrMo steel

“…If they are not discovered in time, the cracks will extend under the action of alternating loads and eventually lead to structural failure, which seriously threatens the overall safety of the structure. 5 For cracked structural members, the fatigue crack propagation performance is usually characterized by a compact tensile (CT) specimen [6][7][8][9] with tensile loading or a single-sided cracked specimen 10 with three-point bending loading.…”