Elastomer materials are used in a wide application range and subjected to different loading from which failure of the material results. Because this failure is caused by initiation and propagation of cracks, the application of fracture mechanics methods for the assessment of the material is obvious. A short summary of the methods of technical fracture mechanics including possibilities of determination of crack resistance curves is given. Vulcanizates on the basis of SBR 1500 with various sulfur and carbon black contents were investigated. For describing the crack initiation and crack propagation behavior, several fracture mechanics examination methods were applied. Tear‐analyzer results were used to assess the crack propagation behavior under fatigue‐like loading conditions. Furthermore, for the characterization of the crack resistance of the materials under impact‐like loading conditions, instrumented tensile‐impact tests were performed. To obtain information about the initiation and propagation of a stable crack, quasi‐static fracture mechanics tests were applied. The results of the several tests are discussed in dependence on sulfur and carbon black contents. We found a non‐monotonous behavior of the toughness as a function of carbon black loading. An explanation is given in connection with a percolation‐like transition in filler morphology on larger length scales.
Schematic crack propagation curve for characterizing the fatigue behavior of the vulcanizates recorded in a TFA test. 相似文献
This paper deals with the influence of the testing equipment on impact load measurements. A previously developed method of analysis and processing of the experimental data based on a refined analogical model of the impact event and inverse problem techniques is used. This method makes it possible to obtain the mechanical response of the material, notwithstanding the disturbance of the dynamic effects associated to the test. Results from tests carried out both on falling weight and swing pendulum instrumented testing machines are compared. It is shown that this method can give an accurate estimation of the actual bending force in impact testing independent of the testing equipment. 相似文献
岩土地层结构是影响工程稳定与安全的重要因素,是地质及岩土工程勘测的主要内容。研发了一种地层地质界面识别系统,阐述了其基本组成和工作原理,建立了钻进过程识别码及岩土地层结构实时识别方法;通过花岗岩地基钻进试验研究,确定了岩体风化等级以及土层/散体、碎裂岩体及整体岩体结构的比能值范围,建立了金刚石钻进比能的地层结构分级标准,比能值分别是土层及散体为0.0017~0.6955 k N·m/cm3,碎裂岩体为0.0258~0.9798 k N·m/cm3,整体岩体为0.0018~2.4935 k N·m/cm3。研究结果表明,该方法与岩土勘测结果一致,可用于地层地质及岩土地层结构的实时识别,为岩土工程智能勘测提供了新的途径。 相似文献