Fracture toughness testing results

Fig. 7. Fracture toughness test results for AMg6 at room temperature, 76 K, and 4 K.

Table II. Tensile and Fracture Toughness Test Results... 

Table 2.2 High temperature fracture toughness test results (SEVNB method) [17] (with kind ...

Figure 6. SCF, CNB and SEPB fracture toughness test results for specimens from one lot of alpha silicon carbide [37], SCF fracture toughness values overestimate the correct value if the amount removed, at X nh, is insufficient to remove lateral cracks that interfere with the main precrack.

In the present work, a novel experimental method was proposed to evaluate the modes I-fll fracture toughness of the adhesive interface between concrete and carbon fiber sheets. The validity of the evaluation formula was studied on the basis of the results of finite element analysis. The mixed mode fracture toughness and fracture criterion of the adhesive interface were also studied on the basis of the results of fracture toughness test using the proposed method. 

Figure 13 shows a typical result of fracture toughness test. The abscissa shows the displacement of crosshead. The ordinate shows the load applied to the specimen. 

In order to apply the characterization and structural design of the concrete bridge structures retrofitted with tensioned carbon fiber sheets, the mixed mode disk specimen was proposed and applied to the mixed mode fracture toughness tests. The following conclusions were derived from the results and discussions ... 

Abstract The effects of the amount of rubber, the concentration of fibres and the state of the fibre/matrix interface upon the mechanical behaviour of short glass fibre-reinforced rubber-toughened nylon 6 ternary blends are described. First, tensile tests were carried out on different intermediate materials and then on the ternary blends to derive the stress-strain curves and document the damage mechanisms. Fracture toughness tests were implemented on compact tension specimens and the results were correlated to fractographic observations and acoustic emission analysis to assess the role of the different constituents. 

With the initial aim of evaluating the applicability of the ISO 15024 standard for fracture toughness testing for non-unidirectional composite laminates, ESIS TC4 has conducted a number of round robin studies on cross-ply laminates with different stacking sequences. We report here the results of two test laboratories from the 3 round robin activity in which double cantilever beam (DCB) specimens made from unidirectional (0°/0°-interface) composite laminates were compared to DCB-specimens with 0°/90°- and 90790° interfaces. In the analysis, correlation with observations from the delamination growth (e.g., deviation from the mid-plane) and post-test (e.g., fracture surface) inspection was attempted. The results are compared with some results in the literature. 

Table 1, Round robin results for fracture toughness testing of a modified GF-PMMA...

Results of Fracture-Toughness Tests over the Range of Test Speeds. Figure 4 shows the stress intensity factor, KImax, versus test speed for all the materials tested. The test speed is the true opening displacement rate of the specimen when fracture occurs. It is measured by the optical device, and it can be up to 14 m/s. Typical times to fracture vary from 10 s at the lowest speeds to -150 xs at the highest. 

The presence of unintentional damage in short fiber reinforced compo.sitcs contributes to the relationship that appears to exist between the test results obtained with unnotched tensile tests and notched fracture toughness tests. A correlation is possible, since both these specimens fail in a similar manner where the failure is predominantly associated with the fiber-matrix interphase with little damage or yielding of the matrix beyond the... 

The results of the fracture toughness tests are summarized in Table III and plotted in Fig. 2. The /-integral value (/) for each test was calculated using the... 

Table VII. Results of Fracture Toughness Tests (Compact Specimens)...

Armco Steel Corporation conducted comparison tests on two ferritic nickel alloy steels produced in the U. S. for cryogenic service and one USSR Fe-Cr-Mn austenitic stainless steel. These studies included base plate and weldment composition, microstructure, strength, and fracture toughness. Detailed results were reported at a Soviet-American seminar [ ]. This paper summarizes these earlier publications. 

VI. 19. For some materials, results of fracture toughness tests that are valid in accordance with ASTM E399 [VI. 18] cannot be obtained in the standard tests because of excessive plasticity. Furthermore, some materials may not show unstable fracmre... 

Fracture toughness tests are performed on a selection of materials and fluences. The test conditions comply with the Master Curve methodology. The results are compared to the indirect approach of end-of-Ufe toughness... 

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