Crack Topsolid 7 7 Divided By 7 1: What You Need to Know About TopSolid 7 Split

The relative significance of the factors can be obtained by comparing the coefficients of the factors. Figure 6a depicts the perturbation plot of toughness. A, B, and C curves illustrate the sensitivity of toughness to LT, IP, and ET, respectively. The plot indicates that the toughness of specimens was much more sensitive to LT than other controlled factors. The remarkable point is that IP and ET had a similar influence on the toughness while changing one factor and keeping the others constant. Figure 6b demonstrates the 3D surface plot of toughness in terms of ET and IP. The tough behavior in the printed PLA can be achieved by two procedures. The first is to increase the extruder temperature and decrease IP at the same time. The other is to increase IP and to decrease ET concurrently. The plausible arguments for the improvement in the toughness by the first procedure are the enhancement of interlayer adhesion between plastic strings at higher temperature and the reduction of the trapped air pockets between the strings at lower IP. Moreover, the time required to build the inside sections is considerably dependent on the IP. By increasing IP, the nozzle extrudes more hexagonal pattern lines at the inside sections, which takes more time considering the same printing speed for all cases of IP. Therefore, there is less time for heat transfer and variation in LTs using lower IP, which results in better fusion between plastic strings. Figure 6c depicts the 3D surface plot of toughness in terms of LT and ET. The surface plot indicates that increasing LT and ET at a time results in increasing toughness. In a specimen with higher LT, a smaller number of sections are needed to print the part. Therefore, a specimen with a thicker layer consists of less interlayer bonding, which are potential places to raise stress concentration and crack propagation. Figure 7 is beneficial to compare the interlayer bonding and trapped air using thin and thick LT. In addition, higher LT results in lower heat transfer rates and variation in layer temperatures [24] and consequently, better fusion and adhesion of the extruded layers on the solid layers is expected. Figure 8 demonstrates a schematic of temperature variation in lower and higher LT at the same printing speed. It is evident that printing PLA at lower temperatures results in poor layer bonding. The 3D surface plot (3D-SP) of toughness in terms of IP and LT is presented in Figure 9.

The present model is simulating the slip-dissolution mechanism. The aggressive ions diffused to the crack tip where they act as a catalyst to slow down the repassivation rate of the oxide film. At the crack tip the localized anodic dissolution occurred until an oxide film was produced to repassivate the corrosion process. Due to the constant stresses applied, the oxide film ruptured, and new virgin material was exposed to be dissolved and finally repassivated. This process was consequently repeated, see Figure 1. The environment considered was in the boiling water reactor (BWR) under normal water chemistry (NWC), containing approximately 200 ppb oxidant (O2 + H2O2) in the studied recirculation piping [14]. Considering the high temperature and the low amount of aggressive ions, SCC was assumed to be intergranular and the material considered was austenitic stainless steel in the 304 and 316L series.

crack topsolid 7 7 divided by 7 1

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The surrounding material were describing with elastic-plastic finite element (FE) as a continuum, not considering grain structure or grain orientation. The crack was assumed to propagate between the grains as intergranular stress corrosion cracking (IGSCC). The cohesive model was pioneered by Barenblatt [18] and Dugdale [19]; later, it was put into a computational concept by Hillerborg [20]. The CZM describes the fracture process by introducing a traction separation law (TSL), which is the relationship between closing force and the separation. The TSL by Park et al. [21], called the PPR model, was implemented in the CZM in combination with the degradation feature implemented by Sedlak et al. [22]. The combination was used to change the fracture properties from that of the virgin bulk material to that of the oxide.

The parameter m was related to the passivity kinetic of the oxide film and dependent on the conductivity of the environment [4,31], which is deduced from the aggressive ions in the solutions diffused to the crack mouth.

In Figure 5 the adaptive growth is shown in four steps. In the first initial step (0) in Figure 5a, no current density is present, and in Figure 5b the cohesive elements are in their initial arrangement. In step (1) the maximum current density is present, but the film has not started to grow. The movement is for the boundary cohesive elements, representing only dissolution. In step (2) the film starts to grow, therefore the boundary element nodes are locked and the elements start to grow. The thickness of the element was controlled by Equation (8), which gave the horizontal position of the moving nodes. In the next step (3), the cohesive element containing the oxide film became fully damaged due to the applied loads and its decreasing fracture energy which would correspond to a ruptured oxide film. At this instant, the ruptured oxide film element changed into liquid diffusivity element Dl, making the concentration move forward to interact with the next element. The process repeats itself but with the next element, creating crack advancement.

The CZM parameters were divided in cohesive parameters, degradation parameter, diffusion parameters, and electrochemistry parameters. All the parameters were obtained at 288 C, starting with the cohesive parameters for the virgin material. These were obtained from experimental results [38] and simulations [10]: Tnini=T1ini=2500 MPa, λnini=λ1ini=0.1, αini=βini=1.4 and Φnini=Φ1ini=400 N/m. Iteration for the experimental SCC results by Ford et al. [4] gave the oxide parameters, Tnfull=T1full=250 MPa, λnfull=λ1full=0.1, αfull=βfull=10, and Φnfull=Φ1full=10 N/mm. The degradation parameter χ was set to χ=3, which kept the ductile material behavior until 90% degradation, se Appendix D for TSL shapes with degradation parameter shapes χ=3.

The adaptation was set to run at every iteration. This forced the oxide to grow at every step, showing the actual oxide size by the relative node displacement. Initially the mesh of the cohesive elements was distributed uniformly along the expected crack path. As soon as the routine detected an oxide growth over a certain length (0.01 µm) the upper and lower nodes of the cohesive element were translated to the location of the tip of the oxide film. The result of the initial movement created the oxide film. This movement was repeated after every film brakeage. Both Figure 5 and Figure A2 show the results of the movement. However, sometimes the film would not break before running into the neighboring cohesive element. If this happened the second element was pushed forward Figure A2b,c until the cohesive element with the oxide film breaks. The moved element was sacrificed, Figure A2d, and the neighboring cohesive element took over the oxide film forming process in Figure A2e.

Cementitious material: A generic term for any inorganic material including cement, pozzolanic or other finely divided mineral admixtures or other reactive admixtures, or a mixture of such materials that sets and develops strength by chemical reaction with water. In general, the following are considered cementitious materials: portland cement, hydraulic cements, lime putty, hydrated lime, pozzolans and ground granulated blast furnace slag. [3]

Control joint: A continuous unbonded masonry joint that is formed, sawed or tooled in a masonry structure to regulate the location and amount of cracking and separation resulting from dimensional changes of different parts of the structure, thereby avoiding the development of high stresses.

Crack control: Methods used to control the extent, size and location of cracking in masonry including reinforcing steel, control joints and dimensional stability of masonry materials.

Height-to-thickness ratio: The height of a masonry wall divided by its nominal thickness. The thickness of cavity walls is taken as the overall thickness minus the width of the cavity. 2ff7e9595c