Results Of Strength Analysis Research Articles

Strength analysis of feeding device of coal-bed methane truck-mounted drilling rig

Feeding device is the main working part of coal-bed methane truck-mounted drilling rig. In this paper, through analyzing the structural strength characteristics of the feeding device of the CBM truck- mounted drilling rig, the secondary feeding device and the pulley frame, which are the main bearing components, are selected for strength analysis. The three-dimensional model of the feeding device drawn by solidedge was imported into ABAQUS and the finite element model was established to analyze the main load- bearing parts under the limit condition of strong pulling. The analysis shows that under this working condition, the strength of the feeding device fully meets the design requirements. Finally, through the physical prototype performance test, the strength analysis results of the feeding device of the CBM drilling rig are verified.

Vibration characteristics and strength analysis of two-stage variable-pitch axial-flow fan based on fluid-solid coupling method

The adjustment of the rotor blade installation angle of the two-stage variable-pitch axial-flow fan affects the surface pressure characteristics, which in turn affects the vibration characteristics of the rotor blade. In this paper, the finite element model of two-stage variable-pitch axial-flow fan is first established, and then the modal analysis of blades with aerodynamic and centrifugal loads is presented. The resonance of the blade is analyzed based on the pressure pulsation frequency domain characteristics. Finally, the equivalent stress distribution under variable blade installation angles is explored. Simulation results regarding the natural frequency show that the installation angle of the moving blade has a minimal impact on the natural frequency. In contrast, the centrifugal force load significantly affects the natural frequency of the moving blade. To ensure safety, we maintain a frequency margin of over 24 % to avoid the risk of resonance. Strength analysis results indicate that the maximum equivalent stress on the first-stage and second-stage rotor blades decreases by 43.14 MPa and 45.28 MPa, respectively. This reduction is attributed to a certain centrifugal load and a slight offset in aerodynamic loading. This research can provide guidance for the vibration control and safety research of two-stage variable-pitch axial-flow fan.

Konštrukčný návrh rámu korby pre jednonápravový príves za traktor

This article is focused on the results of the research, which is intended to design of a single-axle tipping tractor trailer. The trailer consists of two main parts, a frame and a superstructure. Both parts of the trailer must undergo strength analyses under determined loading conditions. While results of strength analyses of the frame were already presented on the previous event, this work shows an overview of the strength analysis of the tipping superstructure of the trailer. The structure has been analysed under static loads and dynamical effects have been considered by means of a dynamic coefficient. The task has been performed by application of the Finite Element Method (FEM). Some chosen load cases have been analysed and the distribution of stresses in the structure has been evaluated. Results have shown that the designed structure of the tipping superstructure is able to withstand the given loads and it can be used in practice.

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.

Influences of Air-Voids on the Performance of 3D Printing Cementitious Materials.

This paper focuses on inspecting the influences of anti-foaming agent (AFA) on the performance of 3D printing cementitious materials (3DPC). The mini-slump, spreading diameter, yield stress, and strength of 3DPC were evaluated. Additionally, the air-void content, air-void morphology, and air-void size distribution of mortar with and without 0.05% AFA were assessed through image analysis. The mechanical performance and air-void structure of 3D printed samples were also investigated and compared to that of conventionally mould cast samples. Test results show that an optimal AFA content enables 3DPC to achieve favorable workability and mechanical performance. The addition of AFA exhibits lower air-void content in 3DPC than that of the sample without the AFA addition. This reduction in air-void content is further strengthened by the results of strength analysis. Electron microscope analysis shows that the use of AFA results in the suppressed formation of large air-voids during the process of fresh 3DPC. Moreover, the air-void morphology substantially influenced the mechanical performance of hardened 3DPC.

The Dynamic and Strength Analysis of an Articulated Covered Wagon with the Circular Pipe Design

An articulated covered wagon design was developed. The wagon feature is that the body-bearing elements are made of circular pipes. This technical solution made it possible to reduce the tare weight of the wagon while ensuring the strength conditions. Mathematical simulation of the dynamic loading of the developed articulated covered wagon design was carried out under the main operating conditions. In the calculations of the observed quantities, an application of symmetry with regard to the longitudinal axis of the wagon was used. The accelerations, as the components of the dynamic load acting on the wagon, were determined. The dynamic loading computer simulation results of the developed wagon design are also presented. The strength analysis of the articulated covered wagon supporting structure made it possible to conclude that the strength indexes were within the allowed limits. The wagon bearing structure was analyzed for fatigue strength. The weld strength analysis results of the most loaded part of the wagon-bearing structure are presented. The results obtained for the desired quantities revealed their symmetrical distribution in the wagon structure. This research will contribute to improving the efficiency of railway transport operation.

Correlation Between Levels of Interleukin-6 in Peritoneal Fluid With Degree of Pain, Adhesion, and Endometriosis Fertility Index Score in Endometriosis

Introduction : Endometriosis is a benign gynecological disorder characterized by the presence of endometrial tissue and stroma outside the uterine cavity. Several theories have been proposed to explain the occurrence of endometriosis, one of which is the theory of inflammation. Endometriosis lesions can produce inflammatory cytokines, resulting in their increased levels in the peritoneal fluid. This process causes disruption in pelvic anatomy, ovarian function, prostaglandin production and growth factor production that causes pain, adhesions and infertility. Interleukin-6 (IL-6) is an important and potential inflammatory cytokine in assisting the diagnosis of endometriosis. These cytokines act as activating macrophages that can stimulate endometrial cell proliferation and modulate the secretion of other cytokines such as IL-10, IL-13 and TNF-α which augments the inflammatory process. High levels of IL-6 in the peritoneum are relatedto advanced endometriosis associated with pain, severe pelvic adhesions and embryotoxic effects leading to infertility. The effect of IL-6, both local and systemic, on the growth of endometriosis lesions and its associated symptoms is great that this cytokine is considered an important marker.Objective : This study aims to determine the relationship between local inflammatory factors (IL-6 in peritoneal fluid) obtained during laparoscopy with the degree of pain, the degree of adhesions and the correlation with the Endometriosis Fertility Index (EFI) score in endometriosis patients.Material and methods : This is a quantitative analytic research with a cross sectional study design which was conducted on 22 patients with endometriosis. Prior to the laparoscopy, historical factor (EFI score) was recorded and an assessment of the pain scale was performed by filling out a questionnaire. Intraoperatively, the peritoneal fluid was obtained. If the peritoneal fluid was found, it was taken directly with a volume of 3-5 cc using 10 cc syringe. If no fluid was found, peritoneal rinsing was performed using 0.9% NaCl fluid, then 3-5 cc fluid was aspirated using a 10 cc syringe. Subsequently, an examination was carried out using the RayBio Human IL-6 ELISA Kit. During the laparoscopy procedure, the degree of adhesion of the pelvic organs was assessed by looking at the shape and how the adhesions can be separated. Surgical factor (EFI score) was assessed intraoperatively to obtain data for the least function score, AFS endometriosis score and AFS total score. Statistical analysis was performed using paired t test and correlation test.Results : The mean age of the respondents was 34.86 ± 6.11 years, 81.8% were nulliparous, 100% were married, 100% experienced both primary and secondary infertility and 81.8% had no prior pregnancy history. In the study, it was found that IL-6 levels of peritoneal fluid were higher in patients with the degree of severe pain (P <0.05) compared to moderate with the results of 32.58 ± 7.31 pg/ml and 25.39 ± 2.70 pg/ml. IL-6 levels were found to be higher in grade three adhesions than grade two (P <0.05) with results of 32.78 ± 6.65 pg/ml and 23.86 ± 2.18 pg/ml. The mean peritoneal fluid IL-6 levels were 30.75 ± 7.01 pg/ml and the mean EFI score was 4.09 ± 2.09. The correlation of IL-6 levels in peritoneal fluid with EFI score showed a value of r = -0.448 which had moderate strength and a negative pattern, indicating that the higher the IL-6 level of peritoneal fluid, the lower the EFI score (P <0.05).Conclusion : There is a relationship between IL-6 levels of peritoneal fluid in endometriosis with the degree of pain and the degree of adhesion, where IL-6 levels were found to be higher in the degree of severe than moderate pain (P <0.05), higher in third degree adhesions than second degree ( P <0.05). There was a correlation between IL-6 levels of peritoneal fluid with EFI score (P <0.05) with a negative pattern of moderate strength analysis results (r = -0.448).Keywords: Endometriosis, Interleukin-6, Degree of Pain, Degree of Adhesion, Endometriosis Fertility Index Score

Fluid - structure interaction analyze for the centrifugal compressor 3d impellers

The article deals with the issues of the 3D impellers strength analysis for the different centrifugal compressors. Two air compressors are considered, the first for General industrial use, the second for turbocharging the internal combustion engine. The third compressor is designed for the turboexpander unit that operating at high pressure medium. The materials of the impellers were steel, titanium and aluminum alloys. The expediency of using the Fluid-Structure Interaction approach for the strength analysis is considered for these compressors. With the FSI approach, a coupled CFD-FEA solution is performed. Gas-dynamic forces from the medium pressure are taken into account in the impeller strength or vibration analysis. The Ansys package is selected as the program for analysis. CFD models are built and configured in the Ansys CFX. The FEA solution carried out in the Ansys Static structural. The results of strength analysis are compared with and without pressure forces for all impellers. As a result, there were no significant differences in the two solutions for the air compressors. However, for high-pressure compressors, the results of the coupled solution showed the need to take into account the CFD solution. Based on the obtained data, a graph of the reliability coefficient dependence on the increase in the suction pressure in the range from 1 to 100 bar is plotted.

Strength analysis of excavator bucket based on normal digging trajectory and limiting digging force

In view of the phenomenon that the excavator bucket is damaged before it reaches the theoretical life in the actual normal digging process. Based on the continuous trajectory theory, the three-segment continuous trajectory excavated alternately by bucket and rod is selected as the normal digging trajectory. The theoretical digging force (TDF) and limiting digging force (LDF) on the normal digging trajectory are calculated, compared, and analyzed. The influence of bucket structure strength and modal under two different digging force loads on normal excavation trajectory is analyzed. The constrained mode and free mode analysis of the bucket are carried out, and the modal analysis results are compared with the strength analysis results. The results show that on the selected normal digging trajectory, the LDF considering normal force and resistance moment is generally larger than the TDF, and the influence of the LDF load on the bucket structure strength is also larger. The results provide an explanation for the premature damage of the bucket in the process of normal digging.

Simplified selection of optimal shell of revolution

Relevance. Architects and engineers, designing shells of revolution, use in their projects, as a rule, spherical shells, paraboloids, hyperboloids, and ellipsoids of revolution well proved themselves. But near hundreds of other surfaces of revolution, which can be applied with success in building and in machine-building, are known. Methods. Optimization problem of design of axisymmetric shell subjected to given external load is under consideration. As usual, the solution of this problem consists in the finding of shape of the meridian and in the distribution of the shell thickness along the meridian. In the paper, the narrower problem is considered. That is a selection of the shell shape from several known types, the middle surfaces of which can be given by parametrical equations. The results of static strength analyses of the domes of different Gaussian curvature with the same overall dimensions subjected to the uniformly distributed surface load are presented. Variational-difference energy method of analysis is used. Results. Comparison of results of strength analyses of six selected domes showed that a paraboloid of revolution and a dome with a middle surface in the form of the surface of rotation of the z = - a cosh( x/b ) curve around the Oz axis have the better indices of stress-strain state. These domes work almost in the momentless state and it is very well for thin-walled shell structures. New criterion of optimality can be called “minimum normal stresses in shells of revolution with the same overall dimensions, boundary conditions, and external load”.

Dynamic problems in the operation of overresonant vibrating screens

The paper presents the results of the numerical analysis of the stress state (FEM) which is created in the construction elements of the PZ3R vibrating screen in normal operation conditions. These results where compared to and verified by tensometric, displacement and acceleration measurements. The results of strength analyses indicated the directions of possible modifications of structural elements of the screen, and also confirmed the desirability of their implementation, but in strictly specified order.

Effects and mechanisms of slag reinforced coal gangue geopolymers

This paper uses alkali activators with the modulus of 1.30 to prepare coal gangue geopolymers, thereby studying the reinforcement effects of slag content on coal gangue geopolymers. Besides, XRD, TG-DTG, and SEM are introduced to analyze changes in the microstructure and further explore the change mechanisms. The experimental results show that the compressive strength of coal gangue geopolymers increases with the increase in slag content. Compared to the P.O 42.5 pure cement paste, coal gangue geopolymers can obtain higher early strength. Besides, the 28d compressive strength of coal gangue geopolymers is greater than P.O 42.5 pure cement specimens when the slag content is 20%. The geopolymer products of slag-containing coal gangue geopolymers are C-(A)-S-H and N-A-S-H gels. The two kinds of gels, which are highly compatible, jointly constitute the network-like disordered structure of polymers. The XRD, TG-DTG and SEM results are consistent with the strength analysis results.

A working design of a bulldozer blade as additional equipment of a compaction drum roller

The main purpose of the performed works was to develop a concept of a bulldozer blade mounted to the road roller. The paper presents the main assumptions, design stages, results of strength analyses of the blade, which can be used in a road roller. Because the elements that push the components of machines operating on construction sites, in mines and in the agricultural environment, the elaborated element would enable wider use of the roller. Based on the FEM analyses, it has been confirmed that the developed load bearing structure is characterized by full operating strength. The designed blade meets the initial assumptions and can be used as equipment of heavy machines.

Strength Analysis of a Freight Bogie Frame under the Defined Load Cases

This work presents results of strength analyses of a modified freight wagon bogie frame. It consists of two main parts. The first part is addressed to introduction of the structure of a freight wagon bogie frame. It is a modified frame structure, which reflects current requirements of modern railway transport means. The conditions for rail vehicles approval and the main load cases, which every bogie frame must meet for commissioning, are described. The next part deals with computer modelling and analyses of this bogie frame. Strength analyses were performed using the FE method and they were focused on the assessment of stresses in the frame structure. Loads definition and the method of calculation were based on valid norms and standards.

Analiza wytrzymałościowa belki opryskiwacza z wykorzystaniem systemów CAD/CAE

Presented are the results of strength analysis of the Pilmet boom sprayer. After creating the numerical model of the boom, a static analysis was carried out. Stresses and displacements were determined using the finite element method for different variants of the folding boom position.

Verification of Strength of the Welded Joints by using of the Aramis Video System

Abstract In the paper are presented the results of strength analysis for the two types of the welded joints made according to conventional and laser technologies of high-strength steel S960QC. The hardness distributions, tensile properties and fracture toughness were determined for the weld material and heat affect zone material for both types of the welded joints. Tests results shown on advantage the laser welded joints in comparison to the convention ones. Tensile properties and fracture toughness in all areas of the laser joints have a higher level than in the conventional one. The heat affect zone of the conventional welded joints is a weakness area, where the tensile properties are lower in comparison to the base material. Verification of the tensile tests, which carried out by using the Aramis video system, confirmed this assumption. The highest level of strains was observed in HAZ material and the destruction process occurred also in HAZ of the conventional welded joint.

Optimum topology design for the concentrated force diffusion structure of strap-on launch vehicle

The thrust from the booster of strap-on launch vehicle is transmitted to the core via the strap-on linkage device, so the reinforced structure to diffusion the concentrated force should be employed in the installation site of this device. To improve the bearing-force characteristics of the concentrated force diffusion structure in strap-on linkage section and realize the lightweight design requirements, topology optimization under multiple load cases is conducted for the concentrated force diffusion structure in this study. The optimal configuration finally obtained can achieve 17.7% reduction in total weight of the structure. Meanwhile, results of strength analysis under standard load cases show the stress level of this design scheme of the concentrated force diffusion structure meet design requirements and the proposed topology optimization method is suitable for the design of the concentrated force diffusion structure in concept design phase.

Analysis of structural elements made of composite materials with defects

The paper presents an improved technique and the results of strength analysis for the aircraft structural elements with a structural defect like an arbitrary shape delamination.

Tests and Examination of Drive Sheave in Mine Skip Hoist

Abstract This article describes a certain stage of work aimed at strength analysis of the structure of drive sheaves in mine shaft hoists. The work was initiated in connection with the emergence of cracks in those sheaves as a result of operation, and is an attempt to develop a new improved design of the drive sheave. The first stage involved several series of strain gauge measurements of stress in the drive sheaves of machines exposed to their rated load. Measurement technology and results are described in detail in (Rokita & Wójcik, 2013). The results of those measurements were the basis for FEM stress analysis and discussion of the changes in the structure of those sheaves. This article focuses on a description of the developed computational models for the currently used sheaves, and presents the results of strength calculations. As a result of those actions, a new drive sheave design was developed, for which a computational model was also prepared and FEM calculations were performed. Comparison of the results of calculations for both sheave models is, therefore, also an assessment of the impact of the proposed changes to the design of the drive sheave on its strength and durability. It was decided to adopt the results of strength analysis of the sheave assembly currently in service as the baseline for this assessment. This required not only the performance of a strength analysis on the basis of a specially developed drive sheave calculation model, but also identification and assessment of the allowable stress values for the analysed structure.

Structure improvement and strength finite element analysis of VHP welded rotor of 700°C USC steam turbine

The optimized structure strength design and finite element analysis method for very high pressure (VHP) rotors of the 700°C ultra-super-critical (USC) steam turbine are presented. The main parameters of steam and the steam thermal parameters of blade stages of VHP welded rotors as well as the start and shutdown curves of the steam turbine are determined. The structure design feature, the mechanical models and the typical position of stress analysis of the VHP welded rotors are introduced. The steady and transient finite element analysis are implemented for steady condition, start and shutdown process, including steady rated condition, 110% rated speed, 120% rated speed, cold start, warm start, hot start, very hot start, sliding-pressure shutdown, normal shutdown and emergency shutdown, to obtain the temperature and stress distribution as well as the stress ratio of the welded rotor. The strength design criteria and strength analysis results of the welded rotor are given. The results show that the strength design of improved structure of the VHP welded rotor of the 700°C USC steam turbine is safe at the steady condition and during the transient start or shutdown process.