Loading Arrangement Research Articles

Numerical characterization of local and global non-uniformities in the load distribution in ball screws

Load distribution in ball screws is a representation of the ball contact stress, and it is fundamental to understanding the behavior of these machine elements. This work aims to conduct a multi-variable analysis of the load distribution in ball screws. For this purpose, a numerical tool is developed for the generation and calculation of ball screw finite element (FE) models, which has been validated against the state of the art. This tool is based on the combination of an analytical contact model and the use of high-order FE models for the analysis of the load distribution of ball screws and stands out for its accuracy (less than 1% error against high-order FE models), adaptability, versatility (models are generated with more than 20 design variables and they can be introduced as components in larger models) and efficiency (being the computational time 1.25% of that of a high-order FE models) with respect to other existing models. Many different design variables (number of start threads, pitch, contact angle, ball size, slenderness and load arrangement) are studied in order to obtain a general characterization of the morphology of the load distribution in ball screws. Among them, the most influential variables on the load distribution and therefore on the structural behavior of ball screws are, load arrangement (with ratio r variations of up to 25% on the same ball screw) and slenderness (with ratio variations of up to 13% on ball screws with two turns of difference). The two most characteristic features, the non-uniformity at a local and global level are identified, along with as the possible causes of their appearance and the consequences that they may cause.

Application of Machine Learning Methods for Pallet Loading Problem

Because of continuous competition in the corporate industrial sector, numerous companies are always looking for strategies to ensure timely product delivery to survive against their competitors. For this reason, logistics play a significant role in the warehousing, shipments, and transportation of the products. Therefore, the high utilization of resources can improve the profit margins and reduce unnecessary storage or shipping costs. One significant issue in shipments is the Pallet Loading Problem (PLP) which can generally be solved by seeking to maximize the total number of boxes to be loaded on a pallet. In many previous studies, various solutions for the PLP have been suggested in the context of logistics and shipment delivery systems. In this paper, a novel two-phase approach is presented by utilizing a number of Machine Learning (ML) models to tackle the PLP. The dataset utilized in this study was obtained from the DHL supply chain system. According to the training and testing of various ML models, our results show that a very high (>85%) Pallet Utilization Volume (PUV) was obtained, and an accuracy of >89% was determined to predict an accurate loading arrangement of boxes on a suitable pallet. Furthermore, a comprehensive analysis of all the results on the basis of a comparison of several ML models is provided in order to show the efficacy of the proposed methodology.

An Experimental Investigation on the Mechanical Properties including Strength and Flexural Toughness of Mortar Reinforced with Steel-Carbon Hybrid Fibers

This paper presents the results of an experimental investigation conducted to evaluate the mechanical properties, including strength and flexural toughness of hybrid fiber-reinforced mortar (FRM) containing various combinations of steel and carbon fibers with different material characteristics. The mortar specimens were mixed with steel and carbon fibers in the mix proportions of 100 + 0%, 75 + 25%, 50 + 50%, 25 + 75%, and 0 + 100% by volume at a total volume fraction of 1.0%. The flexural performance (flexural strength and toughness) of the mortar specimens was obtained using the third-point loading arrangement stipulated in the test methods of ASTM C 1609/C 1609/M and KS F 2566. In addition, compressive strength was also measured according to the KS F ISO 679 test method. Their mechanical properties were examined and compared with plain mortar (PM) at the age of 28 days. The test results showed the highest compressive and flexural strengths in the hybrid FRM reinforced with 75% steel fibers + 25% carbon fibers, confirming the synergistic reinforcing effect of the steel and carbon hybrid fibers. However, the hybrid FRM reinforced with 50% steel fibers + 50% carbon fibers has obtained slightly low flexural strength but owned the highest flexural toughness and hence can be judged as the most appropriate combination to be employed in hybrid FRM to improve the flexural toughness. Moreover, the fractured FRM surface was also observed via scanning electron microscopy (SEM) after platinum coating in vacuum. These results would be of great help in establishing the microstructural mechanism of hybrid reinforcing fibers in the cement matrix.

Using measured rotation on a beam to detect changes in its structural condition

ABSTRACT A recent survey of Europe’s highway infrastructure has concluded that almost half of Europe’s bridges are nearing the end of their design live. Work in the wider Structural Health Monitoring sector is aiming to develop reliable and cost-effective methods for verifying condition, remaining service life and safety of ageing structures. Most bridge condition assessment methods are based on deflection, acceleration or strain measurements. This paper looks at the possibility of using rotation measurements as a main parameter to identify damage. This study looks at numerical analyses of a moving point load on a one-dimensional bridge model to provide the theoretical basis of the proposed damage detection method. It is shown that when local damage occurs, even when it is remote from a sensor location, it results in an increase in the magnitude of rotation measurements. This study looks at how best to exploit this fact for damage detection. A number of damage scenarios, sensor locations, and load arrangements are investigated in this study and their influence on the ability of the algorithm to detect damage are reported.

Kadar gula darah atlet sepak bola remaja setelah pemberian diet beban glikemik

Effect of diets with glycemic load arrangement on blood glucose levels in young soccer athletes Background: Carbohydrate arrangement considering the glycemic index (GI) and glycemic load (BG) are important to support the performance of athletes.Objective: To examine the effect of diets with glycemic load arrangement on blood glucose levels in young soccer athletes.Methods: Quasi-experimental study on 14 male young soccer players aged 15-18 years old at Terang Bangsa Soccer School. Each subject completed 4 trials separated by at least 7 days as a washout period. Diets provided consist of high GI with high GL diet (H-H), low GI with high GL diet (L-H), high GI with low GL (H-L), and low GI with low GL diet (L-L). Collected data were fasting blood glucose level (BGL 0), blood glucose level one hour after intervention (BGL 1), blood glucose level two hours after intervention (BGL 2), and blood glucose level after exercise (BGL 3).Results: The results of paired t-test analysis showed that there were differences between fasting blood glucose level and blood glucose level one hour after intervention, blood glucose level one hour after intervention and blood glucose level two hours after intervention, blood glucose level two hours after intervention and blood glucose level after exercise in the H-H and L-H diet group. In the L-L diet group, there were differences between BGL 2 and BGL 3. One-Way ANOVA analysis showed that there were no significant differences in blood glucose levels one hour after the intervention, blood glucose level two hours after intervention, and blood glucose level after exercise between groups.Conclusions: High glycemic load diets influence the increase in blood glucose levels at 1 hour postprandial and after exercise. Low glycemic load diets influence the increase in blood glucose levels after exercise. Diets with the arrangement of glycemic index and glycemic load did not affect blood glucose levels between diet groups.

Shear strength reduction of aluminium lipped channel beams due to web openings

Aluminium members are recently being used as main structural elements in residential, commercial and industrial buildings. Aluminium Lipped Channel Beam (LCB) is one of the popular thin-walled sections used in different applications in construction. Web openings are incorporated in these sections to accommodate building services when they are used as beams. Even though the bending, shear and web crippling behaviours of these sections were investigated in the past, their structural behaviour with web openings have not been investigated. Hence, experimental and numerical studies were conducted in this research to investigate the shear behaviour of these aluminium LCBs with web openings. An aspect ratio of one was considered in this study. A total of 17 tests were conducted first to investigate the shear behaviour of aluminium LCBs with circular web openings using three-point loading arrangement. Finite element models were developed with appropriate loading and boundary conditions and validated using the experimental results. A detailed parametric study was then undertaken using the currently available roll-formed aluminium LCBs with different thicknesses, grades and web opening sizes. The ultimate shear capacities and the shear capacity reduction factors obtained from the tests and finite element analyses were compared with the currently available design rules. This paper presents the details and results of the experimental and numerical studies on the shear behaviour of aluminium LCBs with circular web openings and the comparison with current and recently proposed design rules.

Affibody-Derived Drug Conjugates Targeting HER2: Effect of Drug Load on Cytotoxicity and Biodistribution.

Affibody molecules hold great promise as carriers of cytotoxic drugs for cancer therapy due to their typically high affinity, easy production, and inherent control of the drug molecules’ loading and spatial arrangement. Here, the impact of increasing the drug load from one to three on the properties of an affibody drug conjugate targeting the human epidermal growth factor receptor 2 (HER2) was investigated. The affibody carrier was recombinantly expressed as a fusion to an albumin-binding domain (ABD) for plasma half-life extension. One or three cysteine amino acids were placed at the C-terminus to which cytotoxic mcDM1 molecules were conjugated. The resulting drug conjugates, ZHER2–ABD–mcDM1 and ZHER2–ABD–mcDM13, were characterized in vitro, and their biodistribution in mice carrying HER2-overexpressing SKOV3 xenografts was determined. Increasing the drug load from one to three led to a decrease in affinity for HER2, but a significantly more potent cytotoxic effect on SKOV3 cells with high HER2 expression. The difference in cytotoxic effect on other cell lines with high HER2 expression was not significant. In vivo, an increase in drug load led to a 1.45-fold higher amount of cytotoxic mcDM1 delivered to the tumors. The increase in drug load also led to more rapid hepatic clearance, warranting further optimization of the molecular design.

Multi-objective sensor placement optimization for structural response estimation under spatially varying dynamic loading of bridges

Although a lot of different types of sensors are available in the market only a limited number of sensors can be installed on a structure. Proper placement of these sensors plays a vital role in effectively achieving the objectives of a monitoring system. Sensor placement becomes especially critical in the case of bridges where the applied loading keeps on changing its location. A sensor layout that provides good quality structural response estimates for a given applied loading may not yield acceptable results for a different loading arrangement. Further, usually different types of sensors are installed on a structure e.g. strain gauges and accelerometers. These sensors measure different physical quantities having different units and orders of magnitude thus cannot be easily incorporated in a sensor placement optimization (SPO) process. So, this research work proposes a multi-objective sensor placement optimization approach that can effectively deal with different types of sensor measurements and spatially varying loading such as in the case of bridges. The proposed method employs an augmented Kalman filter (AKF) for structural response estimation and a multi-objective genetic algorithm for SPO. The AKF can effectively estimate structural response using a few heterogeneous noisy measurements while incorporating the modeling error. The effectiveness of the proposed method is demonstrated using a numerical example of a 3D truss bridge structure. The results show that the proposed multi-objective optimization method yields a sensor arrangement that remains effective against spatially varying dynamic loading.

Casting position effects on bond performance of reinforcement bars

AbstractThe phenomena associated with the consolidation of fresh concrete (bleeding and plastic settlement) are commonly considered significant for the bond performance of reinforcement. However, rules to take care of such influence for design are not consistent amongst design recommendations and may lead to notable differences. With this respect, two failure modes generally govern the bond failure, namely the spalling of the concrete cover (also called splitting failure) and the pull‐out of the reinforcement. In this paper, a detailed investigation is presented on the influence of bleeding and plastic settlement on both failures modes, in an effort to understand their conceptual differences and to clarify how shall consistent design recommendations be formulated. Such investigation is based on a comprehensive experimental programme, comprising 137 pull‐out tests on specimens with different casting conditions, embedment lengths, loading arrangements and concrete covers. On the basis of the test results, the phenomenological differences between pull‐out and spalling failures are clarified, as well as the main influencing phenomena (particularly the potential presence of cracks and voids under the reinforcement and the mechanical properties of concrete). On this basis, a physically‐consistent approach is presented to consider the casting conditions on the bond performance and failure modes.

Effect of location of load on shear lag behavior of bonded steel-concrete flexural members

Shear lag is one of the governing phenomena considered in the design of flanged flexural members. The effect of the location of load on shear lag is not well understood yet. This paper presents a study to understand the shear lag behavior in the concrete slab of bonded steel-concrete composite flexural members, conducted with the help of a developed three-dimensional finite element model. The effect of the location of load on shear lag behavior is studied with the help of twelve loading arrangements at the service and the ultimate loads. Three effective widths based on different design criteria are used to understand the effect of the location of load on effective width. These effective widths are effective width for deflection at the service load, effective width for maximum stress at the service load, and effective width for bending moment capacity at the ultimate load. The shear lag behavior is found to be significantly affected by the location of the load. Increase in scaled eccentricity causes shear lag to vary from positive to negative.

Assessment of bi-disperse solid particles mixing in a horizontal paddle mixer through experiments and DEM

In the current study, the mixing of bi-disperse particles in a horizontal paddle mixer was investigated through the sampling experimental technique and discrete element method (DEM). LIGGGHTS software was employed as the DEM solver. A close agreement between the simulation and experimental data was observed. Using the calibrated DEM model, the influence of some operating parameters such as impeller rotational speed, vessel fill level, particle number ratio (rn) and particle loading arrangement on the mixing quality was analyzed. A detailed analysis of this specific type of mixer comprising bi-disperse particles has not been reported in literature. It was found that rn had the most significant effect on the mixing performance. It was also found that the diffusion mechanism was dominant over the convection mechanism and in the cases in which the values of the diffusion coefficients of 5 mm and 3 mm particles were close, the best mixing performance was achieved.

An Optimal Phase Arrangement of Distribution Transformers under Risk Assessment

This paper presents a phase arrangement procedure for distribution transformers to improve system unbalance and voltage profile of distribution systems, while considering the location and uncertainties of the wind turbine (WT) and photovoltaics (PV). Based on historical data, the Monte Carlo method is used to calculate the power generation value-at-risk (VAR) of WTs/PVs installed under a given level of confidence. The main target of this paper is to reduce the line loss and unbalance factor during 24-hour intervals. Assessing the various confidence levels of risk, a feasible particle swarm optimization (FPSO) is proposed to solve the optimal location of WTs/PVs installed and transformer load arrangement. A three-phase power flow with equivalent current injection (ECI) is analyzed to demonstrate the operating efficiency of the FPSO in a Taipower feeder. Simulation results will support the planner in the proper location of WTs/PVs installed to reduce system losses and maintain the voltage profile. They can also provide more risk information for handing uncertainties when the renewable energy is connected to the distribution system.

Propagation tests with uniformly distributed cellulosic fire load

In the recent past, the necessity to have a better understanding of fire dynamics and of the full structural response under real fires was the motivation for several large-scale non-standard fire tests. Nowadays, the novel need to better comprehend the fire dynamics behind the so called “travelling fires” underlined the limitations of those non-standard fire tests. The lack of standardised procedures does not allow making effective comparisons and drawing scientific conclusion from these tests. The fire group of Liege University performed eleven non-standard or “natural fire” tests within the context of the RFCS research project TRAFIR sponsored by the E.U. Commission (grant N°754,198). The aim of this experimental campaign was to determine a uniformly distributed fuel arrangement that would lead to a medium fire growth as recommended for office buildings in Eurocode 1. This paper presents the test results in terms of fire growth rate, flame length, temperature along the flame centreline, fluxes at a distance from the fire and temperatures on wood sticks. The outcomes define a uniformly distributed fuel load arrangement leading to a desired fire development and also provide valuable experimental information on the fire dynamics related to fire spread. In conclusion, a well-established methodology to perform natural fire tests has been defined, from the ignition system up to the exact fuel arrangement. This methodology could be used in the future for natural fire tests in order to allow a comparison of different conditions (ventilations, geometry, nature of the boundaries, etc.) while considering the same fire load distribution to understand, for example, the conditions in which a travelling fire can develop or not. The experimental results reported here can also be used to validate or calibrate various existing or future sub-models developed by other authors.

Vibration behavior of timber-concrete composite floors under human-induced excitation

The design of timber-concrete composite (TCC) floors is usually subject to the requirement of serviceability rather than strength. Most studies reported so far focus on the dynamic characteristics of the TCC floor. However, there are few studies conducted on the vibration comfort of TCC floors under human-induced excitation. In this paper, dynamic experiments were performed to obtain the fundamental frequency and the damping ratio of a glulam-concrete composite floor under simply supported and fixed support boundary conditions, respectively. Besides, an in-depth investigation was carried out considering the influences of walking path, step frequency, number of pedestrians, arrangement of walking loads and walking mode on the vibration response of the composite floor. Test results showed that the peak acceleration of the floor increased with an increase in step frequency and the number of pedestrians. Regular walking caused a higher peak acceleration compared to irregular walking. At the same step frequency, marking time caused a larger peak acceleration than normal walking. Three existing analytical models were applied to predict the fundamental frequency of the floor, which conformed to the experimental results. In addition, a calculation model and finite element (FE) models were proposed to predict the peak floor acceleration under a single person walking, and the numerical model results agree well with the test results. A double-index was proposed to evaluate the vibration serviceability of TCC floors; the fundamental frequency of the floor is required to exceed 15 Hz and the peak acceleration ought to be less than 0.15 m/s2.

Accelerated Pavement Testing to Evaluate the Reinforcement Effect of Geogrids in Flexible Pavements

This study presents an accelerated pavement testing (APT) to evaluate the reinforcement effect of geogrids in flexible pavements. A full-scale conventional three-layer flexible pavement structure was constructed, and was divided into one unreinforced section and two reinforced sections with base reinforced by geogrids placed at different depth of base course. The testing program was divided into three parts: performance testing, response testing, and forensic evaluations. The performance testing recorded the development of surface permanent deformation with the number of loadings. The falling weight deflectometer (FWD) was employed to investigate deflections and moduli of flexible pavements in the response testing. The excavation of pavements was to further analyze reinforcement mechanisms. Test results demonstrated the benefits of incorporating geogrids in base course in reducing the permanent deformation and improving the modulus of base course. Compared with the unreinforced section, accumulated permanent deformations in the two reinforced sections decreased significantly, with a drop of 13%–37%, and the back-calculated moduli of the reinforced base increased by 58%–78% after APT. It was possible that sufficient permanent deformation was needed for mobilizing geogrids to constrain lateral movements of granular particles, to increase the overall structural behavior of the reinforced base course, and to improve the stress distribution on the subgrade. These interaction mechanisms were also confirmed in the pavement trench. For a pavement system consisting of a thin surface and base layer, the proper placement position of geogrids was at the base–subgrade interface for this test and loading arrangement.

Analysis of top- and side-contact MLGNR interconnects: impact on crosstalk, stability, and electromigration

In a recent nanoregime, the cross-coupling capacitance plays an important role due to the high packing density of integrated circuits. It can significantly affect the overall interconnect performance of an IC that can reduce the reliability, durability, and stability of silicon technology. In order to alleviate these problems, this work demonstrates shielded side-contact (SC) and top-contact (TC) multilayered graphene nanoribbon (MLGNR) interconnect to demonstrate stability and cross talk reliability issues. At 32 nm technology, an equivalent single-conductor Pi-type network is proposed for shielded SC- and TC-MLGNR for different spacing and interconnect lengths. Besides, the impact of temperature and higher current density is demonstrated. It is observed that the conventional interconnect material such as Cu exhibits 52.31% faster electromigration breakdown as compared to graphene at 1000 K. Further, the cross talk-induced delay is analyzed for shielded TC-and SC-MLGNR using driver–interconnect–load arrangement. An improved crosstalk-induced delay of 59.36% and 95.97% is observed for SC-MLGNR as compared to a TC-MLGNR with active shielding for an average spacing range of 5–20 nm at local and global lengths, respectively. Furthermore, the power delay product and peak noise of active-shielded SC-MLGNR exhibit on an average 96.82% and 38.20% improvement in comparison with active-shielded TC-MLGNR for the spacing of 5 nm at global length. Moreover, the Nyquist plot is used to demonstrate higher stability of SC-MLGNR than TC-MLGNR at 32 nm technology. Therefore, the overall system performance demonstrates that the active-shielded SC-MLGNR can be treated as a suitable choice for future VLSI technology.

Seismic Bearing Capacity of Shallow Strip Footings on Sand Deposits with Weak Inter-layer

The main objective of this study is to evaluate the ultimate seismic bearing capacity of a shallow strip footing resting on a frictional soil stratum containing a weak intervening layer. The majority of the studies throughout the literature pertain to the static loading condition. The previous seismic analyses have also been devoted to the studies on the bearing capacity of shallow strip footings resting on a two-layered soil. The influence of weak middle layer on the pseudo-static seismic bearing capacity of shallow foundations is the main focus of the present study. To determine the seismic bearing capacity, the limit equilibrium method (LEM) was combined with the pseudo-static seismic loading approach. Bearing capacity was defined by a single equivalent coefficient which combines the contributions of cohesion, surcharge and soil weight. A two-wedge failure surface, known as the Coulomb failure mechanism, was adopted to model the slip lines in each layer to calculate the seismic bearing capacity of the overlying shallow strip footing. The Particle Swarm Optimization (PSO) algorithm was invoked to seek the optimal bearing capacity value under different strength and loading conditions. In order to verify the validity of the presented formulations, the results were compared with some Finite Elements Method (FEM) analyses available in literature. Furthermore, the influence of the embedment depth, thickness, and strength of the weak inter-layer on the seismic bearing capacity of the shallow footing is investigated in the presence of different seismic loading arrangements. The results of this study could be very helpful in the seismic analysis and design of shallow foundations overlying a soil medium containing a weak layer of various strengths.

Novel Efficacious Utilization of Fuzzy-Logic Controller-Based Two-Quadrant Operation of PMBLDC Motor Drive Systems for Multipass Hot-Steel Rolling Processes

This study investigates the rough steel-rolling process, which requires repeated and rapid bidirectional hot-rolling operations and proposes a fuzzy-logic-controller-based brushless electric DC (BLDC) motor drive system for the same. We present a modeling of the hot-steel rough-rolling process using a set of metallurgical parameters and mechanical equations based on their operating conditions, specific features and characteristics, all obtained from actual data. The above equations and related parameters were modeled in MATLAB/Simulink schematic under variations in temperature and slab thickness corresponding using three different hot-rolled (HR) steel specimens. This led to the creation of a pair of speed and torque- profiles with alternate polarities for successive passes covering the entire rolling process for each steel specimen. A fuzzy logic controller utilized the above profiles on the motor shaft by incorporating speed and current feedback loops to attain reference speed and calculation of instantaneous stator currents of the BLDC motor with respective phase sequences, so as to satisfy the torque-profile. Simulation results showing the detailed performance of the drive system are presented. Further, experimental work on a BLD-motor-drive system is presented, along with loading arrangements and an arm controller embedded with control algorithm for the multi-loop feedback system used for the closed loop speed control. The efficacy of the new applications proposed in this study for the first time can be seen from the validation of the results from the BLDC motor with its fuzzy-based controller in terms of simulation and hardware, thereby serving to be an attractive alternative to conventional induction motor drive systems for steel rolling.

New approach for shear design of reinforced concrete slabs under concentrated loads based on tests and statistical analysis

Despite the international research activity, the shear strength of reinforced concrete slabs without shear reinforcement is not yet satisfactorily resolved. In particular, deck slabs of existing bridges often show significant deficits in design shear capacity, although no damage has been reported so far. A test series of 14 large-scale cantilever slabs subjected to concentrated loads was conducted and analysed at the Hamburg University of Technology. Varying the distance between the concentrated load and the support in a previously unexamined wide range led to new considerations regarding the shear capacity in RC slabs.The ultimate and residual loads of the test specimens, as in many other studies on this topic, clearly exceeded the values for vehicle load assumptions in the current standards. In contrast to previous studies, a large shear slenderness in the load arrangement could be realized in the tests. This was the basic requirement for one of the key findings: The critical shear crack occurs locally in the area of load application and not at the support. Thus, shifting the design section for shear close to the concentrated load is reasonable, while in many approaches a critical section close to the support is chosen. Furthermore, the often-used effective width beff, which depends on the distance of single loads to the support, does not seem justified. The shear forces should be determined by finite element analysis, a common method in practice, which can consider the spatial load transfer and the stiffness of the support in a realistic manner.The new design method presented here is therefore not primarily concerned with the shear resistance, as other investigations are, but first on the side of determining the relevant internal shear forces, which are initially higher in the design section proposed here. Only in a second step is a preliminary factor C*Rd,c for the calculated resistance determined by means of a well-founded statistical evaluation. For this purpose, a database with 45 tests on RC slabs has been established. The new design approach provides significant greater shear capacities than the current regulations.

Behaviour of bolted steel splice connections under fire

Steel connections play a crucial role in steel frames subjected to loading both under ambient and elevated temperature conditions. In fact, the susceptibility of a steel structure to failure or collapse especially when exposed to fire is largely contingent on the robustness of the connections, hence, the structural behaviour of connections constitutes a central research theme which has continued to attract significant attention.The results of an experimental and a numerical study on the performance of bolted web-flange splice (BWFS) connections in fire are presented herein. A total of eight connections were tested in a furnace using ISO 834 heating curve and observations on their ductility under elevated temperatures are reported. The specimens were subjected to both moment and shear loads under 3-point and 4-point loading arrangements. The parameters investigated in the tests were connection load ratio, loading configuration, and bolt size. The observed failure modes and ultimate strengths obtained for the connections from the experimental data were compared with strength predictions from EC3 equations and the latter were found to be conservative for all the cases investigated. A finite element model was developed and validated with results from the experiment to enable the effect of bolt grade on the connection behaviour to be studied. Results in the form of temperature versus rotation (T-θ) curves are presented and failure modes are discussed to provide useful insights on the performance of these connections in fire.