Assessment of the Load-Bearing Capacity of Bark-Included Junctions in Crataegus monogyna Jacq. in the Presence and Absence of Natural Braces

2020 ◽  
Vol 46 (3) ◽  
pp. 210-227
Author(s):  
Dean Meadows ◽  
Duncan Slater
Keyword(s):  
Bearing Capacity ◽  
Mechanical Performance ◽  
Mechanical Resistance ◽  
Single Specimen ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Crataegus Monogyna ◽  
Naturally Occurring ◽  
Mode Of Failure ◽  
Control Branch

Bark-included junctions are frequently encountered defects within the aerial structures of trees. The presence of included bark within a branch junction can substantially reduce the junction’s factor of safety. Recent research has found naturally occurring bracing to be a primary cause of the formation of included bark within branch junctions. This study tested the load-bearing capacity of branch junctions in hawthorn (Crataegus monogyna Jacq.) using rupture tests and compared the mechanical performance of “control” branch junctions, bark-included junctions with the natural bracing retained, and bark-included junctions where we had intentionally removed their natural braces by cutting them out. Substantial variability was observed in the failure kinematics of bark-included branch junctions when their natural braces were retained. The type of natural brace present affected the mode of failure of the branch junctions when pulled apart. A single specimen with fused branches presented the strongest form of natural brace in this study, followed by entwining branches, whereas crossing branches were found to provide the least mechanical resistance. This study provides initial evidence that the type of associated natural brace is an important consideration when an arborist is trying to assess the likely mechanical performance of a bark-included junction within a tree and its likelihood of failure.

scholarly journals MODELING OF SOIL LOAD-BEARING CAPACITY AS A FUNCTION OF SOIL MECHANICAL RESISTANCE TO PENETRATION

2015 ◽  
Vol 39 (4) ◽  
pp. 1036-1047 ◽  
Author(s):  
Cícero Ortigara ◽  
Moacir Tuzzin de Moraes ◽  
Henrique Debiasi ◽  
Vanderlei Rodrigues da Silva ◽  
Julio Cezar Franchini ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Agricultural Soils ◽  
Total Porosity ◽  
Soil Bulk Density ◽  
Mechanical Resistance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Preconsolidation Pressure ◽  
Soil Load ◽  
Resistance To Penetration

Estimation of soil load-bearing capacity from mathematical models that relate preconsolidation pressure (σp) to mechanical resistance to penetration (PR) and gravimetric soil water content (U) is important for defining strategies to prevent compaction of agricultural soils. Our objective was therefore to model the σp and compression index (CI) according to the PR (with an impact penetrometer in the field and a static penetrometer inserted at a constant rate in the laboratory) and U in a Rhodic Eutrudox. The experiment consisted of six treatments: no-tillage system (NT); NT with chiseling; and NT with additional compaction by combine traffic (passing 4, 8, 10, and 20 times). Soil bulk density, total porosity, PR (in field and laboratory measurements), U, σp, and CI values were determined in the 5.5-10.5 cm and 13.5-18.5 cm layers. Preconsolidation pressure (σp) and CI were modeled according to PR in different U. The σp increased and the CI decreased linearly with increases in the PR values. The correlations between σp and PR and PR and CI are influenced by U. From these correlations, the soil load-bearing capacity and compaction susceptibility can be estimated by PR readings evaluated in different U.

scholarly journals Congressing kinetochores progressively load Ska complexes to prevent force-dependent detachment

2017 ◽  
Vol 216 (6) ◽  
pp. 1623-1639 ◽  
Author(s):  
Philip Auckland ◽  
Nicholas I. Clarke ◽  
Stephen J. Royle ◽  
Andrew D. McAinsh
Keyword(s):  
Bearing Capacity ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Live Cells ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Naturally Occurring ◽  
Chromosome Congression ◽  
Spindle Microtubules

Kinetochores mediate chromosome congression by either sliding along the lattice of spindle microtubules or forming end-on attachments to their depolymerizing plus-ends. By following the fates of individual kinetochores as they congress in live cells, we reveal that the Ska complex is required for a distinct substep of the depolymerization-coupled pulling mechanism. Ska depletion increases the frequency of naturally occurring, force-dependent P kinetochore detachment events, while being dispensable for the initial biorientation and movement of chromosomes. In unperturbed cells, these release events are followed by reattachment and successful congression, whereas in Ska-depleted cells, detached kinetochores remain in a futile reattachment/detachment cycle that prevents congression. We further find that Ska is progressively loaded onto bioriented kinetochore pairs as they congress. We thus propose a model in which kinetochores mature through Ska complex recruitment and that this is required for improved load-bearing capacity and silencing of the spindle assembly checkpoint.

Role of Collagen Content and Architecture in the Load Bearing Capabilities of Tissue-Engineered Cartilage

2011 ◽  
Author(s):  
M. Khoshgoftar ◽  
C. C. van Donkelaar ◽  
K. Ito
Keyword(s):  
Bearing Capacity ◽  
Network Architecture ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Limiting Factor ◽  
Collagen Network ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Native Cartilage ◽  
Engineer Cartilage

A promising treatment for damaged cartilage is to replace it with tissue-engineered (TE) cartilage. However, the insufficient load-bearing capacity of today’s TE cartilage is an important limiting factor in its clinical application. In native cartilage, collagen fibers resist tension and proteoglycans (PG’s) attract water through osmotic pressure and resist its flow, which allows cartilage to withstand high compressive forces. One of the main challenges for tissue engineering of mechanically stable cartilage is therefore to find the cues to create an engineered tissue with an ultrastructure similar to that of native tissue. Currently, it is possible to tissue engineer cartilage with almost native PG content but collagen reaches only 1/4 of the native content [1]. Furthermore, the specific depth dependent arcade-like organization of collagen in native cartilage (i.e. vertical fibers in the deep zone and horizontal fibers in the superficial zone), which is optimized for distributing loads, has not been addressed in TE’d cartilage. However, the relative importance of matrix component content and collagen network architecture to the mechanical performance of TE cartilage is poorly understood, perhaps because this would require substantial effort on time consuming and labor-intensive experimental studies. The aim of this study is to explore if it is sufficient to produce a tissue with abundant proteoglycans and/or collagen, or whether reproducing the specific arcade-like collagen network in the implant is essential to develop sufficient load-bearing capacity, using a numerical approach.

Mechanical Resistance of Triple Glass Facade Panels

2013 ◽  
Vol 486 ◽  
pp. 84-89
Author(s):  
Petr Bouška ◽  
Radomír Pukl ◽  
Miroslav Špaček ◽  
Miroslav Vokáč ◽  
Tomáš Bittner
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bearing Capacity ◽  
Experimental Investigations ◽  
Mechanical Resistance ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Load Bearing ◽  
Glazed Facade ◽  
Loading Tests

Loading tests of triple glazed facade panels with dimensions of 1.5 x 2.64 m were carried out. The purpose of the tests was to examine mechanical resistance of the glass panes, namely the deformations caused by a local load, to determine degree of interaction between the panes of triple glazing exposed to the loading action and to prove the load bearing capacity of the panels. This experimental investigations were accompanied by finite element analysis.

Predicting failure modes of 3D-printed multi-material polymer sandwich structures from process parameters

2021 ◽  
pp. 109963622110204
Author(s):  
David L Edelen ◽  
Hugh A Bruck
Keyword(s):  
Bearing Capacity ◽  
Process Parameters ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Sandwich Structures ◽  
Sandwich Beam ◽  
Failure Model ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
The Face

The emergence of additive manufacturing (AM) technologies, such as fused deposition modeling (FDM), have enabled the realization of structures with superior mechanical performance through lightweighting and multi-material architectures. However, the complexity associated with the internal geometric features and potential material configurations have also presented new challenges in designing these structures to optimize mechanical performance. In particular, the failure mechanisms and their relationship to the load bearing capacity of the structures may vary compared to analogous structures designed using conventional manufacturing techniques. In this work, we investigate failure modes of 3 D-printed (3DP) multi-material polymer sandwich beam structures manufactured from acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) materials and subjected to three-point bend loading. Digital Image Correlation (DIC) is utilized to understand the effects of different process parameters on the mechanical response of the 3DP structures. ABS and PC dogbone tensile specimens were printed to establish the baseline properties in tension with varying raster angles and infill patterns. Multi-material sandwich beam structures were then printed with honeycomb cores using different processing and architectural parameters, and the failure modes and loads of these structures were compared with predications from a failure model for sandwich structures that accounts for the following conventional failure modes: (1) indentation, (2) face sheet bending, (3) core bending, and (4) core shear. With minor changes in the processing and geometric parameters, failure modes could be shifted from the face sheets to core bending and core shear, as evidenced by the DIC strain field measurements, and the corresponding max load-to-weight ratios could be increased. Estimations of the tensile properties of the face sheets and core were found to be sufficiently accurate when combining classical lamination theory (CLT) and rule-of-mixtures (ROM) models, while the failure model also predicted the load bearing capacity and failure mode in three-point bending with reasonable accuracy.

Increased load bearing capacity of mechanically joined FRP/metal joints using a pin structured auxiliary joining element

2020 ◽  
Vol 62 (1) ◽  
pp. 55-60
Author(s):  
Per Heyser ◽  
Vadim Sartisson ◽  
Gerson Meschut ◽  
Marcel Droß ◽  
Klaus Dröder
Keyword(s):  
Bearing Capacity ◽  
Load Bearing Capacity ◽  
Load Bearing

Load-Bearing Capacity of Direct Inlay-Retained Fibre-reinforced Composite Fixed Partial Dentures with Different Cross-Sectional Pontic Design

2017 ◽  
Vol 68 (1) ◽  
pp. 94-100
Author(s):  
Oana Tanculescu ◽  
Adrian Doloca ◽  
Raluca Maria Vieriu ◽  
Florentina Mocanu ◽  
Gabriela Ifteni ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Fracture Pattern ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Load Bearing ◽  
Reinforced Composite ◽  
Polyethylene Fibre

The load-bearing capacity and fracture pattern of direct inlay-retained FRC FDPs with two different cross-sectional designs of the ponticwere tested. The aim of the study was to evaluate a new fibre disposition. Two types of composites, Filtek Bulk Fill Posterior Restorative and Filtek Z250 (3M/ESPE, St. Paul, MN, USA), and one braided polyethylene fibre, Construct (Kerr, USA) were used. The results of the study suggested that the new tested disposition of the fibres prevented in some extend the delamination of the composite on buccal and facial sides of the pontic and increased the load-bearing capacity of the bridges.

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