Flexural strength biaxial

Figure 3.4. Biaxial orienlalion of polymelhyl methacrylate. Variation of (a) brittle flexural strength and (b) brittle flexural energy with percentage stretch. (After Ladbury )...

The mechanical strength of the composite disk specimens was tested, before and after immersion, under biaxial flexure conditionsn [8-10] with a universal testing machine (United Calibration Corp., Huntington Beach, CA). The biaxial flexure strength (BES) of the specimens was calculated according to mathematical expression (1) [8-10] ... 

The biaxial flexural strength (Uf) was calculated using the following equation [5,55] ... 

Figure 12. Biaxial flexural strength, Op and fracture toughness, Kj of UST dental porcelain before and after ion exchange (IE) at different temperature. In parenthesis is the temperature of IE relative to the glass transition temperature (Tg = 575 C). Data from [57]...

Figure 14. Biaxial flexural strength, Qp after a Vickers indentation at different loads (a) and fracture resistance, Kr, as a function of crack extension, Ac (b), for UST dental porcelain with and without ion exchanges. Data from [63,64]...

Figure 15. Weibull plot of biaxial flexural strength data, Op tor LIST dental porcelain with and without ion exchange. Dotted lines are 95% confidence interval m is Weibull modulus, Uq is characteristic strength, and 05% is fracture stress at 5% fracture probability. Data from [71]...

Figure 17. Biaxial flexural strength, as a function of stress rate (a) and predicted flexural strength as a function of time to fracture (b) for UST dental porcelain, with and without ion exchange, in artificial saliva at 37°C. In a),(Jjo is the scaling parameter and n is the slow crack growth, SCG, susceptibility coefficient. Inert strength was determined at 100 MPa/s in air with a drop of silicone oil on the tensile surface to inhibit the occurrence of SCG. In (b), the slope of fitted curve is related with n. Data from [63,71]...

ASTM-F394-78. Standard test method for biaxial flexure strength (modulus of mp-ture) of ceramic substrates. West Conshohocken American Society for Testing Materials 1996. 

The conventional filler, Raysorb T-4000, is a commercial unreactive particulate glass that is widely used in conventional composite resins, and was also incorporated either untreated or silanated. In all cases, discs of material of dimensions 13 mm diameter X 1mm thickness were prepared and cured from each side with a conventional dental curing lamp through a glass microscope slide for 40 s. They were stored in water for 24 h, after which they were tested for net water uptake and biaxial flexure strength [23]. Results are shown in Table 4.4. 

G338 sample had a slightly lower net water uptake as well as much greater biaxial flexure strength than the one with the untreated filler. This demonstrates the importance of silanation of the filler in order to obtain the greatest stress transfer from matrix to filler, and hence the maximum possible strength. 

Re-formulated polyacid-modified composite resins have also been found to have properties that decline following water uptake and secondary acid-base reaction (Table 4.6). In one study that demonstrated this, Dyract AP was shown to have lower compressive and biaxial flexure strength values following soaking in water for 4 weeks than they did at 24 h [32] (Table 4.6). By contrast, when stored in dry conditions, strengths were not significantly different between 24h and 4 weeks. 

In this study. Macro-defect-free cements were produced by addition of two different epoxy resins, and their strength and durability properties were investigated from mechanical, structural and morphological point of view by using biaxial flexural strength test, contact angle measurements and atomic force microscopy (AFM). 

Biaxial flexural strength tests were carried out on both water stored and dry specimens for 7 and 28 d, respectively, in accordance with ASTM F-394 [16]. 

Biaxial Flexural Strength of MDF Cements with Diglycidyl Ethers of Bisphenol A and F. 

Figure 1 Biaxial flexural strengths of MDF cements produced with diglycidyl ethers of bisphenol A...

Table 4 Correlation between contact angle, surface energy and biaxial flexural strength of MDF...

Ds-Ws)xlOO/Ds, where Ds, Ws are the biaxial flexural strengths of dry and water-stored MDF... 

C1499-02 Test Method for Monotonic Equi-biaxial Flexural Strength Testing of Advanced Ceramics at Ambient Temperature... 

Table III. Results of fracture toughness, Kic, of samples with disc and bar geometry and biaxial flexural strength, oa, of disc shaped samples. Values followed 1 the same superscript are statistically similar...

Figure 3. Weibull plot of biaxial flexural strength, Of,( data of disc shaped samples saliva at 37°C.

Figure 7. Biaxial flexural strength, ocb, as a function of fracture toughness, K c of disc shaped samples. Dotted line represents Of.h = lOO.Ku..

---