Numerical Strength Analysis Research Articles

On a river-barge numerical strength analysis in head design wave loads

On a river-barge numerical strength analysis in head design wave loads

Verification analysis for quality control of load-bearing superstructures (Kyzyl)

It is currently relevant to perform the quality control of load-bearing superstructures using verification calculations, which provide strength, rigidity and crack resistance of elements.Purpose: The development of analytical and numerical methods to evaluate bendable reinforced concrete elements of a ribbed floor slab.Methodology/approach: Well-known normative methods for the strength analysis of reinforced concrete structures; comparison of analytical and numerical results obtained in the LIRA software package.Research findings: Well-known formulas for bending elements are used for static calculations. The analysis of the limit state of the floor slab using analytical and numerical methods allows assessing the structural state with sufficient accuracy. The structural analysis shows some discrepancies, which require correction in the future.Originality/value: numerical strength analysis of bent reinforced concrete elements.

Predicting the Remaining Useful Life of Light Aircraft Structural Parts: An Expert System Approach

This paper introduces an expert system approach for predicting the remaining useful life (RUL) of light aircraft structural components by analyzing operational and maintenance records. The expert system consists of four modules: knowledge acquisition, knowledge base, inference, and explanation. The knowledge acquisition module retrieves data from mandatory records, such as aircraft logbooks and mass and balance sheets. The knowledge base stores specific remaining useful lives (SRULs) for different load profiles that are determined using numerical strength analysis. The inference module utilizes the Palmgren-Miner rule to estimate the accumulated fatigue damage of the structural component based on the input data and the knowledge base. Lastly, the explanation module links the accumulated damage to the maintenance program and suggests the appropriate maintenance action. The Cessna 172R main landing gear leg is utilized as a case study, demonstrating the variance of RUL depending on the operating conditions. The objective of this approach is to enhance light aircraft maintenance decision making and advance operational safety.

Experimental and numerical analysis of strength and deformation of large‐scale steel‐composite adhesive joints subjected to fatigue followed by static loading

AbstractThis work reports a study of the fatigue behaviour and quasi‐static strength of full‐scale adhesively bonded steel‐composite joints. Three joints with an approximately 10‐mm‐thick layer of methyl methacrylate adhesive were manufactured in dockyard conditions. One specimen was tensile tested till failure, while two specimens were subjected to ~3.5 million fatigue cycles, followed by a residual tensile test supported with digital image correlation. The shear, longitudinal and peel strain values within the adhesive bondlines are significantly higher at the gripped sides due to the asymmetrical design of the steel brackets. All specimens showed a significantly higher shear strength than the design values defined by the shipbuilder. Fibre Bragg sensors monitored strains at steel and composite constituents and allowed to detect damage onset and evolution in tensile tested specimens. A finite element model of the joint was developed with material and interface properties based on dedicated small‐scale experiments. The simulation results of strains during a static load test corresponded closely to the DIC measurements. All specimens failed near the composite‐adhesive interface due to delamination of the composite panel.

Numerical Strength Analysis of Laser-Welded Differential Housing and Gear Considering Residual Stress.

In order to avoid slackening of differential housing and gear joined by bolts, the laser-welding process is proposed in this paper, and the strength of a connecting joint was estimated by numerical analysis with consideration of welding residual stress. The process parameters of laser welding for dissimilar materials QT600 cast iron and 20MnCr5 structural alloy steel were introduced, and chemical composition analysis and microstructure analysis were conducted on the welded joints. The finite element model of laser-welded differential housing and gear was established to obtain the welding residual stress by applying a moving heat source. To verify the accuracy of the simulated result, static pressing tests were employed. The maximum tensile residual stress was 319.4 MPa, located at the same point as the maximum temperature. The simulated stress agreed well with the experimental data. Finally, the dynamic strength of laser-welded differential housing and gear under forward, reverse, and start-up conditions was assessed by regarding welding residual stress as the initial stress field, which showed that all safety factors were greater than 1.4.

Material Model Effect for Simulating a Single-Lap Joint with a Blind Rivet.

This paper concerns the influence of the material modeling method on the results of strength analyses. The research object was a single lap joint with a blind rivet (ISO 12996). The results of numerical strength analysis for various configurations of material models with material and contact nonlinearity were compared not only with the experimental results of such a connection but also with the values estimated using classical analytical tools (pressure stress and Hertz stress). The research aimed to determine how the results of numerical analyses (FEMs) were influenced by the method of modeling the material model and how it relates to the experimental results. As part of the analyses, a discrete riveted model and material models were constructed. The analyses took into account various load cases (from 10 to 90% of the connection capacity) to better illustrate the relationship between the numerical and experimental results. As a result of the conducted analyses, it was determined that the linear-elastic model was an acceptable and suggested solution (with a load of up to 90% of the load capacity of the joint connection) for further tests. The work was summarized with general and specific conclusions relating to all cases of numerical modeling. In addition, the summary includes suggestions for future works.

STATIC BENDING STRENGTH OF SANDWICH COMPOSITE PLATES WITH TETRACHIRAL HONEYCOMBS

The article presents a numerical strength analysis of sandwich plates with solid face layers and tetrachiral honeycomb core layer under static bending conditions. An aluminum alloy was chosen as the material of plates. For honeycomb core layers, the discretization (number of unit cells) and the relative density were varied with a constant thickness. Calculations were performed for the case of bending with rigidly clamped ends and three-point bending within the framework of the theory of elasticity by the finite element method. The strength analysis enables one to determine the load values, at which the maximal stresses according to the von Mises criterion were equal to the conventional yield stress of the material. The aim of this work is to study the effect of discretization and relative density of honeycomb core layers of tetrachiral type on the str ength of sandwich plates.

Numerical analysis of strength for an endoprosthesis made of a material with graded lattice structures

The most common causes of conducting a hip revision surgery after total hip replacement are aseptic loosening (aseptic instability) of the endoprosthesis, bone destruction as a result of contact with the endoprosthesis, and a periprosthetic fracture. These are the effects of load transfer to the bone tissue in arthroplasty resulting due to the difference in stiffness of the endoprosthesis and the bone. Titanium alloy is widely used in endoprostheses manufacturing because of its high biocompatibility, good wear properties, and corrosion resistance, but such endoprostheses are stiffer than the femur. These problems have aroused interest in searching for the best materials and topology for a femoral implant. Nowadays, additive technology is of great interest as it enables to create materials with graded density. These materials consist of multiple lattice structures with variable parameters and topology. By varying the parameters of lattice structures, one can adjust the mechanical properties of the material as required. These materials find their application in hip endoprostheses manufacturing, allowing to adjust the parameters of the lattice structures and deliver a product with femur-like mechanical properties. The porous structure also ensures bone tissue ingrowth into the prosthesis. The authors designed and simulated an endoprosthesis made of graded density lattice structures with femur-like mechanical properties. Using a numerical simulation software ANSYS Mechanical, authors determined the effect of the topology on the structural behavior of the femur and defined the endoprosthesis-femur combined performance under various load cases.

Modeling and computing of stress and strain distribution in UHMW polyethylene elements of chosen artificial human joints

Abstract The aim of the study was to present numerical strength analysis of the virtual knee and hip joints for the most popular tribological pairs used in prosthetic arthroplasty based on the Finite Elements Method. FEM makes it possible to calculate the stress in particular elements of the tested models. The research was dedicated to elucidate abrasive wear mechanisms during surface grinding of a polyethylene UHMW and a metal elements of endoprostheses. Strong adhesion was found between the abrasives and workpieces, which might be attributed to the chemical bonding between the abrasives and workpieces in synovial liquid. Therefore, the wear of UHMWPE is both chemical and physical. Abrasive wear effect, as a result of the abrasive wear process, is associated with material loss of the element surface layer due to the separation of particles by fissuring, stretching, or micro-cutting.

The Influence of Low-Temperature Restorative Heat Treatment on the Structure and Mechanical Properties of Boiler Drum Metal after Long-Term Operation

The drum metal properties of the BKZ-160-100FB and TP-85 boilers installed at the Irkutsk TETs-11 combined heat and power plant were investigated after these boilers had been in operation for 259 000 and 224 000 h, respectively, and after they had been subjected to low-temperature restorative heat treatment, which was carried out with steam produced by an external boiler after replacing all unions installed in the drum’s water volumes. “Plugs” made of grade 22K carbon steel and of grade 16GNM low-alloy steel cut from the drum shell rings were used as research subjects. The samples were subjected to metallographic analysis, tensile tests, impact bending test, and hardness measurement test. The results of tensile tests carried out at room temperature and at the metal operation temperature are presented. The results of drum metal U-notched specimens impact strength tests obtained at room temperature are given. Impact strength tests on V-notched specimens were carried out for samples after their metal had been subjected to low-temperature restorative heat treatment in the temperature range from –10 to +80°C. Based on the results of the V-notched specimens tests, the ductile constituent in the fractures was determined, and the drum metal ductile-to-brittle transition temperature was determined. The microstructure and mechanical properties that the drum metal had after having been in operation and having passed subsequent low-temperature restorative heat treatment were in compliance with the requirements of the relevant regulatory documents. After the boiler drum metal had been subjected to low-temperature restorative heat treatment, the studied steel samples showed a higher proof strength both at room temperature and at the operation temperature. Based on the data obtained from the investigations of boiler drum metal after it had been in operation and then subjected to low-temperature restorative heat treatment, technical diagnostics, and numerical strength analysis, it was recommended to extend the service life of the drums at their design (certificate) parameters.

Strength Analysis of a Ducted Axial Fan Blade

This paper presents a numerical strength analysis of a ducted axial fan blade. Ducted axial fans are a large group of fluid-flow machines. The analysis was designed to determine the causes of cyclic failures of a ventilation unit. The paper presents a reverse engineering approach to the mapping of the fan blade’s geometrical features. The geometrical features were mapped by triangulation from the scanning images produced by a 3D optical scanner. These were followed by simplifying assumptions on which the numerical calculations were based. The numerical calculations were carried out at the operating rotational speeds of the ducted axial fan’s rotor. The course of the numerical calculations is described, and their results are also presented herein. The results are represented on colour maps of stress distribution for selected structural elements of the fan blade. The stress distribution at a blade cross-section was compared to CT scans of the fractures of failed rotor blade airfoils. Final conclusions were developed which show that the design engineering process of fans should feature optimisation of the fan’s efficiency, including the strength and performance parameters, which should include the service life of the fan.

Composite materials for strengthening of load-bearing wooden structures in historical buildings

The results of tests of a composite material made on the basis of glass cloth and an epoxy binder in the form of ED-20 resin are considered in the article. The main strength and elastic characteristics of the composite are obtained experimentally, including taking into account the set of strength of the epoxy matrix in time. It is shown that for the proposed composite material, a set of strengths for all main types of stress state up to the level of 70% of the calculated value occurs on average for 16 days, to a level of 90% of the calculated one for 45 days, 95% of the calculated value for 60 days from the beginning Curing the composite on the surface of the structure. Statistical analysis of the strength and deformability parameters of the composite material, comparison of the strength of the composite material and wood at different reliability levels for the main types of stressed state of wooden elements in building structures are given. The results of numerical strength analysis in the ABAQUS program complex of the state of stress of a compound at different thicknesses of a composite material are presented.

Effects of confining pressure and loading path on deformation and strength of cohesive granular materials: a three-dimensional DEM analysis

This paper is devoted to numerical analysis of strength and deformation of cohesive granular materials. The emphasis is put on the study of effects of confining pressure and loading path. To this end, the three-dimensional discrete element method is used. A nonlinear failure criterion for inter-granular interface bonding is proposed, and it is able to account for both tensile and shear failure for a large range of normal stress. This criterion is implemented in the particles flow code. The proposed failure model is calibrated from triaxial compression tests performed on representative sandstone. Numerical results are in good agreement with experimental data. In particular, the effect of confining pressure on compressive strength and failure pattern is well described by the proposed model. Furthermore, numerical predictions are studied, respectively, for compression and extension tests with a constant mean stress. It is shown that the failure strength and deformation process are clearly affected by loading path. Finally, a series of numerical simulations are performed on cubic samples with three independent principal stresses. It is found that the strength and failure mode are strongly influenced by the intermediate principal stress.

The effect of the gantry crane beam cross section on the level of generated stresses

The gantry cranes are currently one of the most popular devices to transporting loads. They can be used in many industries. This study focuses on the numerical analysis of only the portable gantry crane. The mathematical and numerical model of mechanical phenomena in the gantry crane beam was presented in this paper. This problem was solved by using of the Finite Element Method (FEM). The analysis was made to the cross-section of gantry crane beam which was the I-beam or box beam. The numerical simulations are limited to numerical analysis of strength of the gantry crane beam which was loaded by the motion of the load force along its length. As a result of the calculations, the stresses and displacements of the structure of gantry crane were obtained. The influence of beam shape change and changing the loading force position on generate the equivalent stress in the crane beam was evaluated. The research performed, which allows the estimated of the stress state, pointing out the critical areas and values, were made in order to increase the strength of the structure of the gantry crane.

Experimental and Numerical Strength Analysis of Stepped Lap Adhesive Joints Subjected to Static Tensile Loading

Experimental and Numerical Strength Analysis of Stepped Lap Adhesive Joints Subjected to Static Tensile Loading

Numerical Analysis of Stress Fields Generated in the Gantry Crane Beam

The cranes are currently one of the most common devices for transporting loads and can be applied in many industry areas. This paper includes the numerical strength analysis only of the gantry crane beam. The mathematical model and numerical simulations of mechanical phenomena in the gantry crane beam are presented in this paper. The problem was solved by the finite element method. Analysis was made to the gantry crane beam, which cross-section was the I-beam or T-beam and it was loaded different loads. One takes into consideration in the numerical model the motion of the crane trolley along the beam. As a result of the computations carried out, the stresses and displacements of the structure of gantry crane were obtained. The influences of shape change of the crane beam on the Huber-Mises stress in the steel beam were estimated. It sought to that the maximum value of Huber-Mises stress induced in the gantry crane beam was less than the strength of material, because then the design is safe.

Structural Design and Impact Test of a Suspension Mountain Bicycle Frame by Using FEM Analysis

The paper deals with numerical strength analysis of a prototype of full suspension mountain bicycle frame. Frame and its suspension were specially designed to meet predetermined requirements establishing the final properties of bicycle. In the design, also other aspects such as the driving style, characteristic of lines and the figure of driver were taken into account. In this regard, the final design is completely unique. In the paper there are described two impact tests: drop mass and frame drop, which are defined in standard EN ISO 14 766. Both tests were carried out using Finite Element Method.

Numerical analysis of jerry can strength under static and dynamic loads

Such material as high-density polyethylene is used for producing jerry cans, fuel tanks, liquid storage and transportation tanks. Significant shortcomings that may arise in the strength analysis of five-liter jerry cans for storing petroleum products were determined. Based on the APPROX software system using the finite element moment scheme, a system that allows the numerical strength analysis of jerry cans of different shapes and sizes, with the possibility to set different physical and mechanical properties of materials, including composite materials, in a particular statics and dynamics problem statement was implemented. A finite-element model of the jerry can was built, and numerical analysis of the strength under static and dynamic loads taking into account the load nature (stacked storage, kick) was performed. As a result of the numerical analysis, the values of the stress-strain state of the jerry can were obtained, and stress concentration zones were identified. The data is important since it allows to determine the optimal wall thickness for this kind of structures and define optimal storage conditions.

English

English

Experimental and Numerical Strength Analysis of Double Lap Joints Subjected to Tensile Loads

Abstract In this paper the mechanical behaviour of double lap joints (DLJs) bonded with adhesive was analyzed. The stress-strain behaviour was investigated along the overlap length and adherend thickness in DLJs subjected to tensile loads. The stress analyses were performed by finite element method (FEM). The FEM calculations were performed using ANSYS (12.0.1). Experimental results were compared with the FEM results and were found to be quite reasonable. The results show that the failure loads are increased with an increase in adherend thickness. The stress-strain behaviour changes depending on adherend thickness and overlap length. Both FEM stress analyses and experimental results revealed that failure occurred around the edge zones of the overlap length due to the effect of shear stresses, while the failure at the edges of the adhesive layer originated from the peel stress in tensile.