Load-bearing capacity and resonance stability of inelastic beams and plane trusses with initial defects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dragan D. Milašinović ◽  
Ljiljana Kozarić ◽  
Smilja Bursać ◽  
Miroslav Bešević ◽  
Ilija Miličić ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Damage Mechanics ◽  
Ductile Material ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Stability Problems ◽  
Material Defects ◽  
Fundamental Frequencies ◽  
Stiffness Reduction

PurposeThe purpose of this paper is to contribute to the solution of the buckling and resonance stability problems in inelastic beams and wooden plane trusses, taking into account geometric and material defects.Design/methodology/approachTwo sources of non-linearity are analyzed, namely the geometrical non-linearity due to geometrical imperfections and material non-linearity due to material defects. The load-bearing capacity is obtained by the rheological-dynamical analogy (RDA). The RDA inelastic theory is used in conjunction with the damage mechanics to analyze the softening behavior with the scalar damage variable for stiffness reduction. Based on the assumed damages in the wooden truss, the corresponding external masses are calculated in order to obtain the corresponding fundamental frequencies, which are compared with the measured ones.FindingsRDA theory uses rheology and dynamics to determine the structures' response, those results in the post-buckling branch can then be compared by fracture mechanics. The RDA method uses the measured P and S wave velocities, as well as fundamental frequencies to find material properties at the limit point. The verification examples confirmed that the RDA theory is more suitable than other non-linear theories, as those proved to be overly complex in terms of their application to the real structures with geometrical and material defects.Originality/valueThe paper presents a novel method of solving the buckling and resonance stability problems in inelastic beams and wooden plane trusses with initial defects. The method is efficient as it provides explanations highlighting that an inelastic beam made of ductile material can break in any stage from brittle to extremely ductile, depending on the value of initial imperfections. The characterization of the internal friction and structural damping via the damping ratio is original and effective.

Parametric design of surface textures on journal bearing

2015 ◽  
Vol 67 (4) ◽  
pp. 359-369 ◽  
Author(s):  
Hui Zhang ◽  
Guangneng Dong ◽  
Meng Hua ◽  
Feifei Guo ◽  
Kwai Sang Chin
Keyword(s):  
Bearing Capacity ◽  
Journal Bearing ◽  
Parametric Design ◽  
Load Bearing Capacity ◽  
Rectangular Array ◽  
Load Bearing ◽  
Content Type ◽  
Surface Textures ◽  
Capacity Enhancement ◽  
Hydrodynamic Influence

Purpose – The main purpose of this paper is to understand and model the hydrodynamic influence of surface textures on journal bearings. Design/methodology/approach – In the model, a rectangular array of circle dimples is used to modify the film thickness expression. In full film and cavitation regions, classical Reynolds equation and Reynolds boundary condition are used as the governing equations, respectively. By setting high load bearing capacity as the main optimal goal, the influence of textures on tribological characteristics is studied to get the optimal distribution and parameters of textures. Findings – The results suggest that the load bearing capacity of a journal bearing may be improved through appropriate arrangement of textures partially covering its sleeve. The reduction of the cavitation area may also be achieved by arranging the textures in divergent region. With a high density distribution of textures which have step depths varying linearly along the circumferential direction of the bearing, the load bearing capacity enhancement seems to give good performance. Comparing with smooth bearing, the load bearing capacity enhancement of such textures is about 56.1 per cent, although the influence of texture diameters for the same area density seems insignificant. Originality/value – The paper shows how surface textures can be designed on journal bearing to improve its tribological performances.

scholarly journals Prediction of Load-Bearing Capacity of Composite Parts with Low-Velocity Impact Damage: Identification of Intra- and Inter-Ply Constitutive Models

2020 ◽  
Vol 1 (1) ◽  
pp. 59-78
Author(s):  
Aleksandr Cherniaev ◽  
Svetlana Pavlova ◽  
Aleksandr Pavlov ◽  
Valeriy Komarov
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Damage Mechanics ◽  
Impact Damage ◽  
Element Model ◽  
Physical Parameters ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Simulation Methodology

Assessments of residual load-carrying capacity are often conducted for composite structural components that have received impact damage. The availability of a verified simulation methodology can provide significant cost savings when such assessments are required. To support the development of a reliable and accurate simulation methodology, this study investigated the predictive capabilities of a stacked solid-shell finite element model of a cylindrical composite component with a damage mechanics-based description of the intra-ply material response and a cohesive contact model used for simulation of the inter-ply behavior. Identification of material properties for the model was conducted through mechanical characterization. Special attention was paid to understanding the influence of non-physical parameters of the intra- and inter-ply material models on predicting compressive failure load of damaged composite cylinders. Calibration of the model conducted using the response surface methodology allowed for identifying rational values of the non-physical parameters. The results of simulations with the identified and calibrated finite element model showed reasonable correlation with experimental data in terms of the predicted failure loads and post-impact and post-failure damage modes. The investigated modeling technique can be recommended for evaluating the residual load-bearing capacity of flat and curved composite parts with impact damage working under the action of compressive loads.

scholarly journals Fire resistance of extruded hollow-core slabs

2017 ◽  
Vol 8 (3) ◽  
pp. 324-336 ◽  
Author(s):  
Kristian Hertz ◽  
Luisa Giuliani ◽  
Lars Schiøtt Sørensen
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Hollow Core ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Standard Fire ◽  
Comprehensive Test ◽  
Building Components ◽  
First Time

Purpose Prefabricated extruded hollow-core slabs are preferred building components for floor structures in several countries. It is therefore important to be able to document the fire resistance of these slabs proving fulfilment of standard fire resistance requirements of 60 and 120 min found in most national building regulations. The paper aims to present a detailed analysis of the mechanisms responsible for the loss of load-bearing capacity of hollow-core slabs when exposed to fire. Design/methodology/approach Furthermore, it compares theoretical calculation and assessment according to the structural codes with data derived from a standard fire test and from a thorough examination of the comprehensive test documentation available on fire exposed hollow-core slabs. Findings Mechanisms for loss of load-bearing capacity are clarified, and evidence of the fire resistance is found. Originality value For the first time, the mechanisms responsible for loss of load-bearing capacity are identified, and test results and calculation approach are for the first time applied in accordance with each other for assessment of fire resistance of the structure.

Deflection behavior and load-bearing period of structural glued laminated timber beams in fire including cooling phase

2018 ◽  
Vol 9 (4) ◽  
pp. 287-299
Author(s):  
Hitoshi Kinjo ◽  
Yusuke Katakura ◽  
Takeo Hirashima ◽  
Shuitsu Yusa ◽  
Kiyoshi Saito
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Shear Failure ◽  
Fire Performance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Glued Laminated Timber ◽  
Cooling Phase ◽  
Timber Beams

Purpose This paper aims to discuss the fire performance of glulam timber beams based on their deflection behavior and load-bearing period, which were obtained from load-bearing fire tests under constant load conditions. Design/methodology/approach In this report, the fire performance, primarily deflection behavior and load-bearing period of glued laminated (glulam) timber beams will be discussed from the standpoint of load-bearing fire tests conducted during the cooling phase under constant load conditions. Then, based on the charring depth and the per section temperature transformation obtained from loading test results, the load-bearing capacity of the glulam timber beams will be discussed using the effective section method and the strength reduction factor, which will be calculated in accordance with the European standards for the design of timber structures (Eurocode 5). Findings In the cooling phase, the charring rate is decreases. However, as the temperature in the cross section rises, the deflection is increases. The failure mode was bending failure because of tensile failure of the lamina at the bottom of the beam. Moreover, a gap caused by shear failure in a growth ring in the beam cross-section in the vicinity of the centroid axis was observed. Shear failure was observed up until 1 to 3 h before end of heating. The calculated shear strength far exceeded the test results. Shear strength for elevated temperature of glued laminated timber is likely to decrease than the shear strength in Eurocode 5. Originality/value Unlike other elements, a characteristic problem of timber elements is that their load-bearing capacity decreases as they are consumed in a fire, and their bearing capacities may continue to degrade even after the fuel in the room has been exhausted. Therefore, the structural fire performance of timber elements should be clarified during not only the heating phase but also the subsequent cooling phase. However, there are few reports on the load-bearing capacity of timber elements that take the cooling phase after a fire into consideration.

Nonlinear modelling and finite element analysis on the load-bearing capacity of RC beams with considering the bond–slip effect

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pandimani Pandimani ◽  
Markandeya Raju Ponnada ◽  
Yesuratnam Geddada
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Bearing Capacity ◽  
Experimental Program ◽  
Nonlinear Behaviour ◽  
Rc Beams ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Bond Slip

Purpose This paper aims to present nonlinear numerical simulations using the versatile finite element (FE) analysis tool ANSYS and theoretical analysis based on code provisions to assess the load-carrying capacity of reinforced concrete (RC) beams under two-point monotonic static loadings. Design/methodology/approach Four quarter-size FE models with load and geometry symmetry conditions were constructed, the load-bearing capacity and associated mid-span deflections at critical points are verified against the full-scale experimental RC beams available in the literature. These developed FE models incorporated the tension stiffening effects and bond–slip behaviour. Theoretical analyses based on Indian standard code IS: 456–2000 and ACI 318–19 were also carried to verify the experimental and numerical predicted moments at critical loading points. Findings The load-deflection curves predicted through FE models exhibit closer corroboration with the experimental curves throughout the loading history. The contour plots for deflections, concrete principal stresses, reinforcement yield stresses are satisfactorily predicted by the FE models, which reveal the complete information of nonlinear behaviour of RC beams. The developed model well captured the initial and progressive crack patterns at each load increments. Practical implications The FE modelling is an efficient, valid and economical tool that is an alternative to the expensive experimental program and can be used to explore, analyse and fully understand the nonlinear response of RC beams under static loadings. Originality/value The ultimate moment capacity evaluated based on ACI 318–19 code provision show a better correlation with the experimental data as compared to the IS: 456–2000 code provision. The ultimate loads and associated centre-span deflections predicted by RN-2, RN-3, RB-12 and RB-16 FE model show a discrepancy of 1.66 and –0.49%, –4.68 and –0.60%, –9.38 and –14.53% and –4.37 and 4.21%, respectively, against the experimental results, which reveals that the developed ANSYS FE models predict consistent results and achieved a reasonable agreement with the experimental data.

Fire resistance of partially encased composite columns subjected to eccentric loading

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abdelkadir Fellouh ◽  
Abdelkader Bougara ◽  
Paulo Piloto ◽  
Nourredine Benlakehal
Keyword(s):  
Bearing Capacity ◽  
Thermal Behaviour ◽  
Analytical Method ◽  
Calculation Method ◽  
Load Capacity ◽  
Simple Calculation ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Composite Column

PurposeInvestigate the fire performance of eccentrically loaded concrete partially encased column (PEC), using the advanced calculation method (ANSYS 18.2, 2017) and the simple calculation method in Annex G of Eurocode 4 (EN 1994-1-2, 2005). This work examines the influence of a range of parameters on fire behaviour of the composite column including: eccentricity loading, slenderness, reinforcement, fire rating and fire scenario. In this study, ISO-834 (ISO834-1, 1999) was used as fire source.Design/methodology/approachCurrently, different methods of analysis used to assess the thermal behaviour of composite column exposed to fire. Analytical method named simplified calculation methods defined in European standard and numerical simulations named advanced calculation models are treated in this paper.FindingsThe load-bearing capacity of the composite column becomes very weak in the presence of the fire accident and eccentric loading, this recommends to avoid as much as possible eccentric loading during the design of construction building. The reinforcement has a slight influence on the temperature evolution; moreover, the reinforcement has a great contribution on the load capacity, especially in combined compression and bending. When only the two concrete sides are exposed to fire, the partially encased composite column presents a high load-bearing capacity value.Originality/valueThe use of a three-dimensional numerical model (ANSYS) allowed to describe easily the thermal behaviour of PEC columns under eccentric loading with the regard to the analytical method, which is based on three complex steps. In this study, the presence of the load eccentricity has found to have more effect on the load-bearing capacity than the slenderness of the composite column. Introducing a load eccentricity on the top of the column may have the same a reducing effect on the load-bearing capacity as the fire.

Analysis of the viscosity dependent parameters of couple stress fluid in porous parallel plates

2018 ◽  
Vol 70 (6) ◽  
pp. 1086-1093 ◽  
Author(s):  
V.S. Madalli ◽  
Siddharama Patil ◽  
Ayyappa Hiremath ◽  
Ramesh Kudenatti
Keyword(s):  
Response Time ◽  
Bearing Capacity ◽  
Couple Stress ◽  
Type Equation ◽  
Couple Stress Fluid ◽  
Parallel Plates ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Pressure Load

Purpose This paper aims to present a detailed analysis to explore the various properties of non-Newtonian couple stress lubricants between parallel porous plates. Design/methodology/approach With reference to the theories based on micro-continuum analysis, a non-linear, non-Newtonian Reynolds type equation is arrived. The closed form solutions obtained clearly indicate the changes in pressure, load bearing capacity and response time because of variation in viscosity of couple stress fluid. Findings It is observed that the viscosity variation factor greatly influences the change in pressure, load carrying capacity and squeezing time. Originality/value It is observed that the nature of lubricants with suitable additives greatly helps in overcoming the adverse effect because of porous surface. Reynolds type equation is analysed using appropriate boundary conditions. The expression for pressure distribution arrived at in turn leads to the analysis of load bearing capacity and response time.

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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