Determination of dynamic bending stiffness of an orthotropic cross-ply composite

1987 ◽  
Vol 1 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Stephen A. Rizzi ◽  
James F. Doyle
Keyword(s):  
Bending Stiffness ◽  
Dynamic Bending

Anomalously low electrostatic bending stiffness of graphene oxide 2D membranes regulates its environmental fate in aquatic ecosystems

2021 ◽  
Author(s):  
Mohamad Ali Sanjari Shahrezaei ◽  
Seyed Mohammad-Reza Taheri ◽  
Hesam Nikfazan ◽  
Alexandra Satalov ◽  
Mohsen Moazzami Gudarzi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Environmental Impact ◽  
Surface Waters ◽  
Aquatic Ecosystems ◽  
Environmental Fate ◽  
2D Materials ◽  
Bending Stiffness ◽  
High Importance

Though deemed to be of high importance for the determination of environmental impact of 2D materials upon their release into surface waters, control over the conformational engineering of atomically thin...

Tables for Frequencies and Modes of Free Vibration of Infinitely Long Thin Cylindrical Shells

1954 ◽  
Vol 21 (2) ◽  
pp. 178-184
Author(s):  
M. L. Baron ◽  
H. H. Bleich
Keyword(s):  
Free Vibration ◽  
Poisson’S Ratio ◽  
Cylindrical Shells ◽  
Bending Stiffness ◽  
Poisson's Ratio ◽  
Underlying Theory ◽  
Half Wave ◽  
Quick Determination ◽  
Circumferential Waves

Abstract Tables are presented for the quick determination of the frequencies and shapes of modes of infinitely long thin cylindrical shells. To make the problem tractable, the shells are first treated as membranes without bending stiffness, and the bending effects are introduced subsequently as corrections. The underlying theory is based on the energy expressions for cylindrical shells. The tables cover the following range: lengths of longitudinal half wave L from 1 to 10 radii a; number n of circumferential waves from 0 to 6. The results apply for Poisson’s ratio ν = 0.30.

Computational Tool for the Dynamic Analysis of Flexible Risers Incorporating Bending Hysteresis

2007 ◽  
Author(s):  
Russell Smith ◽  
Tommie Carr ◽  
Michael Lane
Keyword(s):  
Production Systems ◽  
New Technology ◽  
Fatigue Loading ◽  
Bending Stiffness ◽  
Analysis Tool ◽  
Flexible Pipe ◽  
Recent Developments ◽  
Dynamic Bending ◽  
Increasing Demand ◽  
Bending Response

Non-bonded flexible-pipe risers provide a structurally compliant solution in offshore floating production systems for the recovery of oil & gas. The bending stiffness of the flexible pipe is an important property in designing the riser system to safely withstand extreme and fatigue loading conditions. These risers have two fundamentally different bending stiffness properties that depend on if the riser system is pressurized or depressurized. A depressurized riser has a comparatively small linear bending stiffness. Most riser designs apply this stiffness as its produces conservative (large) bending responses. In recent years, the bending response predicted from the depressurized bending stiffness has proven overly conservative and there has been an increasing demand to consider the larger hysteretic bending stiffness of the pressurized riser. The objective is to reduce the conservatism and achieve an approved safe design. Recent developments have advanced the modeling of flexible riser bending with hysteresis and this capability has now been incorporated into an industry standard finite-element riser analysis tool. This paper describes the background of hysteresis in relation to non-bonded flexible pipes and outlines the methodology of the riser motions software that incorporates bending stiffness with hysteresis. Riser systems where the dynamic bending response is critical to the success of the design are the main applications that will benefit from this new technology. Examples include: i.) The dynamic bending response at the seabed touchdown of a deepwater catenary riser. ii.) Bending at an interface with the riser hang-off or subsea tie-in.

scholarly journals Analytical Determination of the Bending Stiffness of a Five-Layer Corrugated Cardboard with Imperfections

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 663
Author(s):  
Tomasz Garbowski ◽  
Anna Knitter-Piątkowska
Keyword(s):  
Load Capacity ◽  
Element Model ◽  
Critical Discussion ◽  
Bending Stiffness ◽  
Analytical Determination ◽  
Published Data ◽  
Corrugated Board ◽  
Correct Determination ◽  
Corrugated Cardboard

Bending stiffness (BS) is one of the two most important mechanical parameters of corrugated board. The second is edge crush resistance (ECT). Both are used in many analytical formulas to assess the load capacity of corrugated cardboard packaging. Therefore, the correct determination of bending stiffness is crucial in the design of corrugated board structures. This paper focuses on the analytical determination of BS based on the known parameters of the constituent papers and the geometry of the corrugated layers. The work analyzes in detail the dependence of the bending stiffness of an asymmetric, five-layer corrugated cardboard on the sample arrangement. A specimen bent so that the layers on the lower wave side are compressed has approximately 10% higher stiffness value. This is due to imperfections, which are particularly important in the case of compression of very thin liners. The study showed that imperfection at the level of a few microns causes noticeable drops in bending stiffness. The method has also been validated by means of experimental data from the literature and simple numerical finite element model (FEM). The obtained compliance of the computational model with the experimental model is very satisfactory. The work also included a critical discussion of the already published data and observations of other scientists in the field.

Stiffness and strength properties of five paperboards and their moisture dependency

TAPPI Journal ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 71-85
Author(s):  
GUSTAV MARIN ◽  
MIKAEL NYGARDS ◽  
SOREN OSTLUND
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Shear Strength ◽  
Three Dimensional ◽  
Strength Properties ◽  
Bending Stiffness ◽  
Moisture Ratio ◽  
Machine Direction ◽  
Product Series

Five commercial multiply folding boxboards made on the same paperboard machine have been analyzed. The paperboards were from the same product series but had different grammage (235, 255, 270, 315, 340 g/m2) and different bending stiffness. The paperboards are normally used to make packages, and because the bending stiffness and grammage varies, the performance of the packages will differ. Finite element simulations can be used to predict these differences, but for this to occur, the stiffness and strength properties need to be deter-mined. For efficient determination of the three-dimensional properties in the machine direction (MD), cross direction (CD), and Z direction (ZD), it is proposed that the paperboard should be characterized using in-plane tension, ZD-tension, shear strength profiles, and two-point bending. The proposed setups have been used to determine stiff-ness and strength properties at different relative humidity (20,% 50%, 70%, and 90% RH), and the mechanical proper-ties have been evaluated as a function of moisture ratio. There was a linear relation between mechanical properties and moisture ratio for each paperboard. When the data was normalized with respect to the standard climate (50% RH) and plotted as a function of moisture ratio, it was shown that the normalized mechanical properties for all paperboards coincided along one single line and could therefore be expressed as a linear function of moisture ratio and two constants. Consequently, it is possible to obtain the mechanical properties of a paperboard by knowing the structural prop-erties for the preferred level of RH and the mechanical property for the standard climate (50% RH and 23°C).

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