Members Of Section Research Articles

Determination of Optimal Cross-Section Dimensions of Rectangular Hollow Sections Under Oblique Bending: Analytical and Numerical Study.

An insignificant number of rigorous studies have been devoted to the development of analytical procedures that determine the optimal cross-section dimensions of rectangular hollow section (RHS) members subjected to oblique bending, albeit their ubiquity in numerous application fields. In response to this, an analytical procedure has been developed based on the concept of minimizing maximum effective stress in the RHS caused by an applied oblique bending moment, in order to reduce material costs without compromising strength requirements. The RHS members addressed in this study have been assumed to be produced by hollowing out rectangular solid sections at different cross-section area extraction ratios; therefore, only the wall thicknesses of the RHS members have been taken into consideration as design variables. The minimization of maximum effective stress has been achieved by establishing a functional correlation between the cross-section design variables. The proposed procedure allows specifying the optimal cross-sectional dimensions for given different cross-section area extraction ratios and bringing cost-effective use of materials. After the subtle mathematical calculations, the derived analytical expressions have been made available to practical engineering in simple math forms for use in real design applications. The analytical procedure has been validated against numerical results which have been extracted from finite element analyses carried out in Abaqus engineering software.

Pseudosperma calciphilum (Inocybaceae), a new Mediterranean species from Sardinia (Italy), Malta, and Valencia (Spain)

A complete description is provided for Pseudosperma calciphilum (Inocybaceae, Agaricales), a new basidiomycete species from Sardinia (Italy), Malta, and Valencia (Spain) in Europe, along with colour photographs of its macro- and microscopic characters and a comparative study of the similarities and differences from its closest allies. The new species occurs on calcareous soils in Mediterranean habitats preferably under Quercus ilex subsp. ilex and Q. ilex subsp. rotundifolia. Pseudosperma conviviale resembles P. calciphilum in some macro- and microscopic features, but the latter is distinguished by having white velar remnants on pileus, larger spores and by its ecology, as it apparently grows exclusively on calcareous soils. The phylogenetic analyses based on nrITS and nrLSU nucleotide sequence data confirmed that the new species is a member of the former Inocybe section Rimosae sensu stricto, whose species are currently placed in the genus Pseudosperma. The closest relatives are P. melleum, P. conviviale, P. melliolens and P. umbrinellum, from which the new Mediterranean species is well distinguished both morphologically and genetically.

Buckling behavior of cold-formed steel sigma and lipped channel section beam-columns: Experimental and numerical investigation

In this study, the buckling behavior of cold-formed beam-column members with sigma and lipped channel sections under the combined effect of axial load and biaxial bending moment (P-Mx-My) was compared. A total of 30 specimens (15 with sigma sections and 15 with lipped channel sections), each measuring 1500 mm in length, were tested under monotonic loading. The performances of the specimens under eccentric loading such as strength and energy absorption capacity were investigated experimentally and numerically. The local, distortional and global buckling modes that determine the bearing capacity of the section and the length of the sigma and lipped channel member where all these buckling modes can be seen were determined. Finite element analysis (FEA) was performed with Abaqus software, and the numerical results were verified against experimental results. Using the validated finite element model, a comprehensive parametric study was carried out by performing 2894 FEA on sigma and lipped channel section members with various cross-sectional dimensions and lengths. Experimental results show that there are significant differences in load bearing capacity, energy absorption capacity and buckling modes of sigma and lipped channel section members. In the FEA/ AISI-S100 code comparison made at the end of the parametric study, it was determined that differences occurred according to the lengths, cross-sectional properties and loading points of the members. It was determined that the error rate was safer when the lips were subjected to tensile stresses than when they were subjected to compressive stresses. Finally, it was determined that the FEA/AISI-S100 error rate decreased as the length of the sigma-section members increased.

Shear performance of elliptical head one-sided bolt double-lapped joint with plug-in gasket

One-sided bolts are commonly used for bolted connections between closed section members to address the issue of insufficient space for nut installation. Among them, the elliptical head one-sided bolt uses the difference in length between its long and short axes. This allows the bolt head to be inserted into the elliptical bolt hole and subsequently rotated by 90 degrees, effectively achieving anchoring. But the use of elliptical bolt holes may cause some problems, such as bolt slippage and stress concentration around the bolt holes. In this paper, building upon the elliptical head one-sided bolt concept, a novel structure for one-sided bolted connection is proposed, incorporating a plug-in gasket to improve the mechanical properties of the elliptical one-sided bolted joints. Six sets of steel plate double-lapped joints, connected by elliptical head one-sided bolts and plug-in gaskets, were designed for shear resistance tests. A finite element model was designed using ABAQUS, based on the test specimen parameters. By comparing the simulation results with the experimental findings, the reinforcing effect of the gasket on joint stress was analyzed and validated. The results show that the plug-in gasket effectively resolves the excessive slippage issues and enhances the initial stiffness of the joint. Moreover, when pressure is applied to the bolt hole, the plug-in gasket reduces the stress concentration caused by the extrusion between the bolt hole and the bolt shank, thus preventing local premature failure of the bolt hole.

Manajemen Arsip Dinamis di Sekretariat Dewan Perwakilan Rakyat Daerah (DPRD) Kota Binjai

This research was conducted at the Secretariat of the Regional People's Representative Council (DPRD Kota Binjai). The purpose of this research is to find out about how archives are created, used and maintained as well as dynamic archive management constraints so that they can be used according to their functions in the Binjai City DPRD. The research method used is descriptive qualitative. This study intends to reveal the phenomena that exist in the field, namely: how to create archives, use and maintain archives and what constraints are faced in archives management. Furthermore, researchers conducted interviews with 3 staff members of the Administration General Section of the Binjai City DPRD Secretariat. research shows that the creation of archives has not been maximized, the Human Resources of the DPRD Kota Binjai have not been optimal in the use and maintenance of archives, there is no person in charge/special officer who handles incoming and outgoing letters up to the archiving stage, archive storage is still done manually, in storage, archives are stored based on the year of the archive so as to make it less optimal and inefficient in the efficiency of the archive, resulting in the archive not functioning according to its function in terms of creating and using and maintaining the archive.

Reliability analysis of the impact of thickness measurement accuracy on the longitudinal strength assessment of CAP

The reliability analysis of the longitudinal bending strength of ships is conducted using the total probability method, taking into account and analyzing the accuracy error in thickness measurement of transverse section members on existing servicing ships. A mathematical model for calculating failure probability CAP ratings is established. By calculating the CAP rating of an aged LPG carrier, it is observed that when the deterministic method reaches the target rating, the failure probability in rating calculation by the reliability analysis method is high. This indicates a significant influence of thickness measurement accuracy on CAP rating accuracy.

Improvement of CSM for high-strength S690 and S960 unlipped channel columns, beams and beam-columns

Existing design methods that are mainly based on cross-section classification usually predict conservative resistances for high strength steel (HSS) singly symmetric unlipped channel section members. This paper conducted numerical studies on the resistance of cold-formed S690 and S960 HSS channel section members under different loading types. Numerical simulations were firstly carried out to establish suitable finite element (FE) models, and then applied to parametric studies. The obtained numerical results were adopted to assess and modify the continuous strength method (CSM) for the design of cold-formed HSS unlipped channel section members under axial compression or bending loads. An improved beam-column design method of unlipped channel sections was proposed through providing a new linear design curve incorporating the modified CSM formulae, then to evaluate the newly method and the M - N interaction curves specified in existing standards, finally the reliabilities of proposed method were confirmed.

Influence of Internal Pressure on Hollow Section Steel Members in Fire

Structural steel hollow section members are extensively utilized in civil engineering due to their excellent mechanical performance, favourable geometry for corrosion protection, and aesthetic appeal. Degradation in material properties of steel and thermal expansion at high temperatures must be regarded in designs for fire situations. The closed inner space of hollow sections presents challenges at elevated temperatures. The present study examines the effect of expanding air on the stress state in section walls of hermetically sealed circular and rectangular hollow sections. The effect of the gas pressure is calculated analytically and numerically. The pressure of the expanding air may substantially reduce the capacity of a tubular member. The influence on resistance depends on temperature, volume of the air in the tubular member, and geometry of the hollow section. The results of the study indicate that rectangular hollow sections with relatively large width-to-thickness ratios are more sensitive to internal pressure than circular hollow sections. The temperature range where the adverse effect of internal pressure occurs can include realistic critical temperatures in practical design and therefore deserve special attention to ensure the required safety.

Testing and design of cold-formed high strength steel square hollow section columns

An experimental and numerical investigation into the flexural buckling behaviour of cold-formed (CF) high-strength steel (HSS) square hollow section (SHS) members is reported in this paper. A series of 12 flexural buckling tests were conducted on S700 and S900 CF SHS columns. Finite element (FE) models were developed to simulate the experimental observations, which were utilized in a parametric study encompassing a broader range of steel grades and specimen geometries. Subsequently, the current buckling curves in European, North American, and Australian codes was evaluated through reliability analyses. Meanwhile, the effective width method (EWM) and the modified generalized slenderness-based resistance method (GRSM) were compared for slender cross-sections. According to the results of reliability analyses, the modified buckling curves were proposed for CF HSS SHS columns.

Experimental investigation on H-section members with large width-thickness ratios under traverse impact

Experimental work of 12 axially pre-loaded H section columns with large width-thickness ratios under transverse impact load were carried out. The boundary conditions of the specimens were fixed at one end and sliding at another end and the impact position was 1/3 from the bottom of the column. In the test, the main parameters affecting the impact resistance of the members including web thickness, flange thickness, impact energy and axial pressure were studied. Then a finite element analysis FEA model was established to predict the impact behavior of H section members, in which the strain rate effects was considered. Test data of impact force and total deflection from the author were used to verify the accuracy of the FEA model and general good results were achieved. Results demonstrate that increasing the axial load exerts a negative effect on the impulse from impact load and extension of the impact duration. Under certain impact energy, the impact force in plateau stage of impact process was mainly affected by the flange thickness and the peak stage impact forces was mainly affected by the web thickness. Web was main component on the impact resistance of H-section steel column as over 70% of the impact energy was absorbed. Results provide new information on the impact response of H section columns with large width-thickness ratios and the effects of controlling parameters to form an extensive database.

Behaviour and design of high strength steel circular hollow section member under pure torsion

The paper presents a detailed numerical investigation on the performance of high strength steel (HSS) circular hollow section (CHS) member subjected to pure torsion. Three grades of HSS, viz., S700, S900 and S1100, were considered in the study. Finite element (FE) models were initially developed and validated against the available test results. Further, the validated FE models were used for parametric study. Cross-sections of varying thickness and diameters, as well as HSS grades, were considered for the parametric study. The results generated from the parametric study were then utilised to assess the effect of steel grades on the torsional capacities and deformed shapes at ultimate and post-ultimate capacities. The effect of ratio of yield strength to ultimate ratio on the normalised member capacities has also been studied. Furthermore, the applicability of existing design equations for members subjected to pure torsion have been assessed against the FE generated member capacities. Based on the analysis, most of design predictions outlined in European and American Standards, as well as those proposed by various researchers were found unsuitable for design of HSS CHS under torsion. Hence, two modified design equations based on continuous strength method and direct strength method has been proposed. The modified design methods were found to predict more accurate and reliable torsional capacities.

Experimental and numerical investigation on cold-formed steel zed section beams with complex edge stiffeners

This paper describes the experimental and numerical investigation on the flexural performance of cold-formed steel (CFS) zed section members bent about the neutral axis parallel to the flanges. In the test program, twelve pairs of zed section specimens fabricated from steel sheets of grades G450, G500 and G550 were loaded under four-point bending. Three series of sectional shapes, namely the zed sections with plain flanges as well as complex edge stiffeners consisting of double-fold inward and outward return lips, were devised for the test specimens. In the numerical investigation, the finite element model of four-point bending members, which was developed using ABAQUS and calibrated against the experimental results, was adopted to predict the behaviour of CFS unstiffened and edge-stiffened zed section beams over wide ranges of flange-to-web width ratio, lip-to-flange width ratio, return lip-to-lip width ratio and cross-sectional compactness. Furthermore, underpinned by the bending capacities acquired from the 12 experiments and 222 FE analyses in this study as well as 22 tests available in the literature, it was demonstrated that the current direct strength method (DSM) codified in the AISI S100 generally provided conservative flexural strength predictions for the unstiffened zed section members, while led to overall slightly unconservative design for the edge-stiffened zed section beams. In addition, based upon the DSM-based approaches that were addressed in the previous studies to account for the effect of local-distortional interaction, the nominal flexural strengths of the CFS zed section members with simple and complex edge stiffeners were found to be underestimated by 17% to 21% on average. Accordingly, the modified DSM formulae were recommended in this study for the CFS unstiffened and edge-stiffened zed section beams bent about the neutral axis parallel to the flanges.

Determination of the bearing capacity of biaxially bended beams based on the design strength of reinforced concrete

Based on the design assumptions according to Eurocode 2, the concept of determining the value of the design strength of reinforced concrete has been developed for calculating the bearing capacity of reinforced concrete members subjected to biaxial bending. The theorem on the parallelism of the planes of internal and external forces action is applied. The considered design cases are for the most expected forms of the compressed concrete areas, which are characteristic for biaxial bending of beam members. The value of the coefficient of influence of biaxial bending on the characteristics of the member of rectangular section with triangular and trapezoidal forms of the compressed concrete area is obtained. A methodology for calculating the bearing capacity of biaxially bended members based on the application of the design strength of reinforced concrete is brought to the engineering level of application. An example of a calculation is presented, which demonstrates the convenience and effectiveness of the developed method. The proposed method of calculating the bearing capacity of beam member under biaxial bending is approved by comparing the results of calculations with experimental data for 12 samples of biaxially bended beams.

Pengaruh Kompetensi Sumber Daya Manusia, Penerapan Standar Akuntansi Pemerintah dan Sistem Akuntansi Keuangan Daerah terhadap Kualitas Laporan Keuangan: Studi pada OPD Kabupaten Simalungun

This study set out to find out how the use of government accounting standards, regional financial accounting systems, and expertise in human resources all affect the quality of regional financial reports. This study's participants were all 33 Regional Apparatus Organizations (OPD) in the Simalungun Regency. The samples taken in this study were 33 OPD in Simalungun Regency. Each sample each as many as 3 respondents. Respondents in this study were 1 Head of Finance Subdivision, 1 staff member of the finance section, and 1 treasurer at OPD. With a total sample of 99 people. By distributing questionnaires to the relevant respondents, data were gathered. Using SPSS 24, multiple linear regression was used to analyze the data. The findings indicate that the Accounting System for Regional Finance, Government Accounting Standards, and Human Resource Competence all significantly improve the quality of financial reports produced by regional governments. Additionally, the findings indicate that the Accounting System for Regional Finance significantly improves the quality of financial reports produced by regional governments.

Geometrically nonlinear analysis of steel structures with nonsymmetric sections under elevated temperatures

Steel members using nonsymmetric sections are envisioned as popular because of the advancement in manufacturing techniques, in which frame analysis method under extreme scenarios, such as fire hazards, has not been thoroughly established. The element formulation for those members has been commonly derived based on either the updated-Lagrangian (UL) or the total-Lagrangian (TL) methods. However, the UL method is difficult to analyze the steel member exposed to fires because the previous equilibrium conditions may be destroyed due to the material stiffness degradation at elevated temperatures. Nevertheless, the TL method can be used for studying steel members under fire, but it is inefficient, time-consuming, and requires starting-over computation at every temperature increment. To this, the co-rotational (CR) method could be a promising solution for tackling the analysis problems of steel members in fire efficiently and accurately. The CR method separately describes the element and its rigid body movements, such that the material stiffness degradation can be considered at the element level without the starting-over computation at new temperature increments, which is numerically efficient. This paper reformulates the beam-column element formulation with the warping degree of freedom for nonsymmetric section members using the CR method, which can conveniently consider the material degradation and the thermal expansion for the analysis of steel members at elevated temperatures. The lateral-torsional and flexural-torsional buckling of nonsymmetric section members can be captured robustly. Detailed derivation for element formulation is given, and several examples are provided for verifying the accuracy and examining the robustness of the proposed method.

Major‐axis buckling of pin‐ended stainless steel equal‐leg angle section members: FE modelling and design

AbstractThe behaviour and design of cylindrically‐pinned stainless steel equal‐leg angle section members under compression and compression combined with strong‐axis bending are investigated herein. Numerical models are developed by means of shell finite element modelling formulated within ABAQUS and validated against experimental data. A numerical parametric study is then presented considering both hot‐rolled and cold‐formed stainless steel equal‐leg angle section columns alongside beam‐columns with a wide range of cross‐section and member geometries. Finally, new design proposals for pin‐ended stainless steel equal‐leg angle section members under compression and compression plus major‐axis bending are developed and verified against the results of physical experiments and numerical simulations. The proposed design rules are shown to offer substantially more accurate and consistent resistance predictions compared to existing codified design rules.

Stainless steel built-up section stub columns: Testing, numerical modelling and design

This paper presents experimental and numerical investigations into the cross-sectional compressive behaviour and resistances of stainless steel built-up section stub columns. An experimental programme was firstly conducted on six built-up (open) I-sections and seven built-up (closed) tubular sections, with each composed of two identical press-braked stainless steel channel sections assembled by self-tapping screws, and included tensile coupon tests, initial local geometric imperfection measurements and twenty stub column tests. The experimental programme was followed by a numerical modelling programme, where finite element models were developed and validated against test results and then used to conduct parametric studies, aiming at investigating the effect of screw spacings and generating further numerical data over a wide range of cross-section dimensions. For the design of a stainless steel built-up section stub column, the current European code and American specification treat it as two individual channel section members and adopt effective width methods for calculating the cross-section compression resistance of each channel section member. Both design codes were found to result in many unsafe failure load predictions for stainless steel built-up I-section stub columns but conservative failure load predictions for stainless steel built-up tubular section stub columns. Finally, revised codified design rules were proposed by treating each built-up section as a whole and using an equivalent thickness of the overlapped plate elements, and shown to provide accurate, consistent and safe cross-section compression predictions for stainless steel built-up section stub columns.

Testing and Numerical Simulation of the Shear Resistance of Blind-Bolted Aluminum Connections

Due to their high bending stiffness, high torsional stiffness, and high local stability, rectangular section members of Al alloy space structures are frequently utilized as load-bearing elements. However, the joint construction is more complex because of the closed cross-section. To join rectangular section members without drilling holes in them, a variety of blind bolts that can be placed and fastened on one side have been devised. The blind bolts researched in this paper is known as BOM bolt. The shear resistance of BOM-bolted Al alloy connections is investigated using shear testing and finite element calculations of individual bolts and bolt groups. According to the test and numerical simulation results, the formulas for the compressive strength of the aluminum plate and the shear capacity reduction factor of BOM-bolted long connections are derived.

Economic Considerations and Cost-Saving Strategies for Nonsterile Compounding Education

ObjectiveTo determine the economic considerations, including cost-saving strategies, associated with nonsterile compounding education for students in schools and colleges of pharmacy across the United States. MethodsAn electronic survey was sent to the American Association of Colleges of Pharmacy Pharmaceutics Section and Laboratory Instructor's Special Interest Group members. Quantitative and qualitative data were collected about the institution, student cohorts, compounding courses, equipment, budgets, personnel, and cost-saving measures. Descriptive statistics were calculated using SPSS. Open-ended responses were used by respondents if the primary question could not adequately capture their institution-specific information. These answers were added to the study findings. ResultsOf 555 surveys sent, 46 were completed. Reported annual compounding budgets ranged from $3000 to $96,000. Reported annual equipment maintenance costs ranged from $400 to $18,000. Fifty percent of respondents reported students shared equipment, and 29.6% collected a lab fee from students to offset costs. Approximately half of respondents reported the use of cost-saving measures, including contract pricing, purchasing supplies in bulk, price comparisons, use of simulated drugs, re-use of personal protective equipment, and procurement of donations. Fifty percent of respondents employed laboratory assistants to support nonsterile compounding sessions, with paid positions ranging from $200 to $1000 per semester. ConclusionFindings from this study may assist pharmacy administrators and course directors in evaluating the costs associated with nonsterile compounding education across the Academy and, more importantly, determining ways to reduce such costs while maintaining the intent and quality of these courses.

Design of cold-formed high strength steel CHS-to-RHS T- and X-joints at elevated temperatures

The static resistances of cold-formed S900 steel grade tubular T- and X-joints at elevated temperatures have been numerically investigated in this study. Circular hollow sections (CHS) were used as the braces, while square and rectangular hollow sections (SHS and RHS) were used as the chords for both T- and X-joints. In this study, both T- and X-joints were subjected to compression loads. The mechanical properties of cold-formed S900 steel grade hollow section members at elevated temperatures were used to perform the numerical investigation. The static resistances of CHS-to-RHS T- and X-joints were investigated at 400°C, 500°C, 600°C and 1000°C. The finite element (FE) models developed and validated by the authors for ambient temperature and post-fire investigations of cold-formed S900 steel grade CHS-to-RHS T- and X-joints were used in this study to perform numerical investigation at elevated temperatures. A comprehensive FE parametric study, including a total of 768 CHS-to-RHS T- and X-joints, was performed in this study using the validated FE models. Both CHS-to-RHS T- and X-joints were failed by chord face failure and a combination of chord face and chord side wall failure mode. The nominal resistances predicted from design rules given in European code and CIDECT, using mechanical properties at elevated temperatures, were compared with the resistances of CHS-to-RHS T- and X-joints at elevated temperatures. It is shown that the predictions from design rules given in European code and CIDECT are quite conservative but unreliable. As a result, economical and reliable design equations are proposed in this study for predicting the resistances of the investigated joints.