Numerical representation of fracture patterns and post-fracture load-bearing performance of thermally prestressed glass with polymer foil

2021 ◽  
Vol 226 ◽  
pp. 111318
Author(s):  
A. Saputra ◽  
R. Behnke ◽  
W. Xing ◽  
C. Song ◽  
J. Schneider ◽  
...  
Keyword(s):  
Fracture Load ◽  
Numerical Representation ◽  
Load Bearing ◽  
Fracture Patterns ◽  
Polymer Foil

scholarly journals Effect of Marginal Designs on Fracture Strength of High Translucency Monolithic Zirconia Crowns

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Niwut Juntavee ◽  
Sasiprapa Kornrum
Keyword(s):  
Bearing Capacity ◽  
Testing Machine ◽  
Fracture Load ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Two Factors ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
Bonferroni Test ◽  
Inclined Planes

Introduction. Monolithic zirconia is able to achieve certain aesthetic, but its durability in resisting fracture has been questioned, as fractures often originate from margins of restoration. This study determined fracture resistance of highly translucent monolithic zirconia crowns with different margin designs in terms of marginal thickness and collar height. Materials and Methods. Zirconia blanks (Ceramill® Zolid HT+) were selected for the fabrication of zirconia crowns according to different designs, including varying margin thicknesses (light chamfer, CL; heavy chamfer, CH) and collar heights (no collar, NC; low collar, LC; high collar, HC), which resulted in CLNC, CLLC, CLHC, CHNC, CHLC, and CHHC groups (15 crowns each). The crowns were seated on a metal die and loaded vertically through round end punch (θ = 10 mm), contacting with inclined planes of cusp in a testing machine with crosshead speed of 0.2 mm/min until fracture. Videos with a rate of 50 frames/second were used to record fracture. Fracture load (N) and durable period (s) were compared for significant differences using ANOVA and Bonferroni test (α = 0.05). Results. The mean ± sd of fracture load (N) and durable time (s) were 3211 ± 778 and 212 ± 47 for CLNC; 3041 ± 1370 and 188 ± 53 for CLLC; 2913 ± 828 and 192 ± 27 for CLHC; 4226 ± 905 and 245 ± 35 for CHNC; 4486 ± 807 and 228 ± 29 for CHLC; and 4376 ± 1043 and 227 ± 37 for CHHC. This indicated that marginal thickness had a significant influence on load-bearing capacity and durable time (p<0.05). No significant impact of collar height was shown, either on load-bearing capacity or durable time (p>0.05). No interaction between two factors was presented (p>0.05). Conclusions. Heavy chamfer margin provided stronger zirconia crown than light chamfer, but both were capable of withstanding fracture load higher than maximum masticatory force. Neither presence nor absence of collar indicated any impact on strength. Fabrication of zirconia crowns with either heavy or light chamfer margin and either presence or absence of collar, with the consideration of emergence profile, should be considered.

Fracture Strength and Fracture Patterns of Root-filled Teeth Restored With Direct Resin Composite Restorations Under Static and Fatigue Loading

2014 ◽  
Vol 39 (2) ◽  
pp. 181-188 ◽  
Author(s):  
NA Taha ◽  
JE Palamara ◽  
HH Messer
Keyword(s):  
Fracture Strength ◽  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Fatigue Loading ◽  
Test System ◽  
Fracture Load ◽  
Composite Restorations ◽  
Fracture Patterns ◽  
Lower Load ◽  
Number Of Cycles

SUMMARY Aim To assess fracture strength and fracture patterns of root-filled teeth with direct resin composite restorations under static and fatigue loading. Methodology MOD cavities plus endodontic access were prepared in 48 premolars. Teeth were root filled and divided into three restorative groups, as follows 1) resin composite; 2) glass ionomer cement (GIC) core and resin composite; and 3) open laminate technique with GIC and resin composite. Teeth were loaded in a servohydraulic material test system. Eight samples in each group were subjected to stepped fatigue loading: a preconditioning load of 100 N (5000 cycles) followed by 30,000 cycles each at 200 N and higher loads in 50-N increments until fracture. Noncycled teeth were subjected to a ramped load. Fracture load, number of cycles, and fracture patterns were recorded. Data were analyzed using two-way analysis of variance and Bonferroni tests. Results Fatigue cycling reduced fracture strength significantly (p&lt;0.001). Teeth restored with a GIC core and a laminate technique were significantly weaker than the composite group (379±56 N, 352±67 N vs 490±78 N, p=0.001). Initial debonding occurred before the tooth underwent fracture. All failures were predominantly adhesive, with subcrestal fracture of the buccal cusp. Conclusions Resin composite restorations had significantly higher fracture strength than did other restorations. Fatigue cycled teeth failed at lower load than did noncycled teeth.

Load-Bearing in the Ovine Medial Tibial Condyle: Effect of Meniscectomy

1993 ◽  
Vol 06 (02) ◽  
pp. 100-104 ◽  
Author(s):  
D. M. Pickles ◽  
C. R. Bellenger
Keyword(s):  
Knee Joint ◽  
Contact Area ◽  
Mammalian Species ◽  
Total Removal ◽  
Load Bearing ◽  
Human Knee ◽  
Biochemical Effects ◽  
Pressure Sensitive ◽  
Medial Meniscectomy ◽  
Tibial Condyle

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.

Effect of long-term loading on timber load-bearing elements

2015 ◽  
Vol 10 (2) ◽  
pp. 25-34
Author(s):  
Kristian Sogel
Keyword(s):  
Load Bearing

Acute Traumatic Cervical Facet Fractures

2018 ◽  
Vol 1 (2) ◽  
pp. 5
Author(s):  
Shankar Gopinat
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Early Surgery ◽  
Initial Assessment ◽  
Trauma Patients ◽  
Spinal Stability ◽  
Fracture Patterns ◽  
Spine Ct ◽  
Cervical Facet

Acute cervical facet fractures are increasingly being detected due to the use of cervical spine CT imaging in the initial assessment of trauma patients. For displaced cervical facet fractures with dislocations and subluxations, early surgery can decompress the spinal cord and stabilize the spine. For patients with non-displaced cervical facet fractures, the challenge in managing these patients is the determination of spinal stability. Although many of the patients with non-displaced cervical facet fractures can be managed with a cervical collar, the imaging needs to be analyzed carefully since certain fracture patterns may be better managed with early surgical stabilization.

Fatigue Investigation of Elastomeric Structures

2010 ◽  
Vol 38 (3) ◽  
pp. 194-212 ◽  
Author(s):  
Bastian Näser ◽  
Michael Kaliske ◽  
Will V. Mars
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Material Behavior ◽  
Period Effect ◽  
Numerical Representation ◽  
Material Force ◽  
Strain Behavior ◽  
Dissipative Effects ◽  
Elastomeric Materials

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.

Sign in / Sign up

Export Citation Format

Share Document