Negative Moment Research Articles

Seismic Performance of Pu-Pai Fang-Dovetail Mortise and Tenon Joints at Different Degrees of Looseness: Experimental Tests and Theoretical Analysis

ABSTRACT Timber structures frequently experience damage owing to the loosening of dovetail mortise and tenon (DMT) joints. Pu-pai Fang, positioned above the DMT joint, provides structural constraints to the tenon. This study focuses on the seismic performance of Pu-pai Fang-dovetail mortis and tenon joints at different degrees of looseness in traditional timber structures. Critical mechanical indicators, including hysteretic characteristics, bending moment, energy, stiffness, and deformation properties, were systematically analyzed. A theoretical moment-rotation equation was derived by incorporating the combined influences of the rotational degree, vertical displacement, and horizontal displacement. The effects of tenon height, narrowing angle, and friction coefficient on the bearing capacity of the joints were investigated. The results showed that the Pu-pai Fang enhanced considerably the joint load-bearing capacity, with a maximum increase in ultimate bearing capacity reaching 68.7%, while effectively mitigating the capacity degradation associated with increasing joint looseness. Although the tenon pull-out displacement remained constant with increasing looseness, the pull-out ratio increased, leading to earlier attainment of the peak moment and subsequent descending behavior. The load-bearing capacity of the joint decreased when the dovetail height decreased, and its capacity increased when the narrowing angle and friction coefficient increased during exposure to negative bending moments.

Negative real moments of restricted factors in arithmetic progression

Negative real moments of restricted factors in arithmetic progression

The Gamma-Akash probability Model for Survival Analysis of Cancer Patients

The search for a suitable probability models for the survival analysis of cancer patients are really challenging because survival times of cancer patients are stochastic in nature and are highly positively skewed. The classical well-known one parameter and two-parameter probability models rarely provide better fit to survival times of cancer patients. In this paper a compound probability model called gamma-Akash distribution, which is a compounding of gamma and Akash distribution, has been proposed for the modeling of survival times of cancer patients. Many important properties of the suggested distribution including its shape, moments (negative moments), hazard function, reversed hazard function, quantile function have been discussed. Method of maximum likelihood has been used to estimate its parameters. A simulation study has been conducted to know the consistency of maximum likelihood estimators. Two real datasets, one relating to acute bone cancer and the other relating to head and neck cancer, has been considered to examine the applicability, suitability and flexibility of the proposed distribution. The goodness of fit of the proposed distribution shows quite satisfactory fit over other considered distributions.

Behavior of composite beams with UHPC-concrete composite slabs under negative bending moment

Behavior of composite beams with UHPC-concrete composite slabs under negative bending moment

Shear behavior and design of double embedded nuts bolted connectors in negative moment regions of steel-SFRC composite beams

Shear behavior and design of double embedded nuts bolted connectors in negative moment regions of steel-SFRC composite beams

Study on the Fire Resistance of Castellated Composite Beams with Semi-Rigid Restraints

To study the fire resistance of castellated composite beams with semi-rigid restraints, temperature rise tests with constant loads were performed on two full-scale castellated composite beams with circular holes and semi-rigid restraints to compare the influence of whether stiffeners were set or not under semi-rigid restraints on the fire resistance of castellated composite beams. The results indicate that during the fire, the primary failure mode of castellated composite beams with semi-rigid restraints is the buckling failure of the web and lower flange in the negative moment zone at the beam end. Composite beams with stiffeners exhibited less buckling of the web and lower flange than those without stiffeners; for steel beams without stiffeners, the web and lower flange show overall lateral instability. Following the fire, the composite beams initially exhibit downward vertical deformation. After 5–10 min, when the web temperature is around 500 °C, it matures upward to the initial position. After 50 min, when the temperature of the web is around 800 °C, it starts to deform downward continuously. During the cooling stage, the end plates at the lower flange of the steel beam and the steel column show a separation phenomenon. By comparing the joint deformation and the mid-span displacement, the fire resistance performance of semi-rigid restrained castellated composite beams is better than that of hinged and rigid restraints. Numerical simulation analyses were carried out on the castellated composite beams. The simulation results showed a high degree of consistency with the test results, which effectively validated the accuracy and reliability of the proposed finite-element model.

Precision measurements of muonium and muonic helium hyperfine structure at J-PARC

At the J-PARC Muon Science Facility (MUSE), the MuSEUM collaboration is now performing new precision measurements of the ground state hyperfine structure (HFS) of both muonium and muonic helium atoms. High-precision measurements of the muonium ground-state HFS are recognized as one of the most sensitive tools for testing bound-state quantum electrodynamics theory to precisely probe the standard model and determine fundamental constants of the positive muon magnetic moment and mass. The same technique can also be employed to measure muonic helium HFS, obtain the negative muon magnetic moment and mass, and test and improve the theory of the three-body atomic system. Measurements at zero magnetic field have already yielded more accurate results than previous experiments for both muonium and muonic helium atoms. High-field measurements are now ready to start collecting data using the world’s most intense pulsed muon beam at the MUSE H-line. We aim to improve the precision of previous measurements ten times for muonium and a hundred times or more for muonic helium. We review all the key developments for these new measurements, focusing on the high-field experiment, and report the latest results and prospects.

Reliability Analysis of UHPC Bridge Deck Performance under Complex Stress State

AbstractThe combination parts of steel‐concrete composite beams are often subjected to complex stress state, and its performance assessment is particularly important. And the reliability method is an effective method to assess UHPC bridge deck performance in complex stress state. In this paper, six sigma method is used to analyze the reliability of the negative moment zone of steel‐concrete composite beams, and a limit state equation is established with tensile stress and deformation as the control conditions. The analysis results show that reliability analysis can effectively assess the performance of concrete bridge panels, including tensile, compressive and bending properties. Reliability analysis is a necessary way to improve the reliability of UHPC bridge decks, and the six Sigma method is an effective method to analyze the reliability of UHPC bridge decks.

Influence of RPBL connectors in the negative moment zone on fire resistance of steel-concrete continuous composite beams

Influence of RPBL connectors in the negative moment zone on fire resistance of steel-concrete continuous composite beams

Working through a surplus: negative transference in inter-Asia encounters

ABSTRACT This essay takes a step back to look at the local prehistory of Inter-Asia Cultural Studies: Movements. It takes cues from a moment in Chen Kuan-Hsing’s Qu Di-guo (De-imperialization), where the double inscription of the word zhuan-yi, which not only signifies the epistemological “shifting” frame of reference towards Asia—the inter-referencing— but also carries the extra meaning of “transference” in the psychoanalytical sense. The essay attempts to tread the affective dimension of every step of shift/transference on the path of “Asia as method” from Takeuchi Yoshimi to Mizoguchi Yuzo to Chen Kuan-Hsing to Tejaswini Niranjana’s “inter-Asia methodology.” It then looks at an instance of “negative transference” in the history of inter-Asian encounters, or mis-encounters: the Marxist critic Qu Qiu-bai’s encounter with Rabindranath Tagore in 1924 and how the transference is worked through by reconstructing and unfolding the subjective history of “a man of the past.” By doing so, it affirms the negative moments in inter-Asian encounters, for the shift/transference cannot but be working towards/through a certain surplus that comes with our “geo-colonial historical” (Chen) subject position as the “Thing-in-between” (Liu).

Negative moments as the signature of the radial density at small distances

The present paper proposes a robust evaluation of any radial density at small distances using negative-order radial moments evaluated in momentum space. This evaluation provides a valuable insight into the behavior of a given radial density in the vicinity of r=0, and puts strong emphasis on the importance of measuring form factors at large squared four-momentum transfer, a domain essential for the determination of negative order moments. A specific attention is paid to the regularization scheme directly affecting the numerical determination of the radial density’s parametrization. The proposed method is applied to non-relativistic study cases of the nucleon electric (GEn,GEp), and proton magnetic GMp form factors. The validation is performed through comparison of the results of the approach to the analytically determined Maclaurin expansion - in the vicinity of r=0 - of the radial density function. The method is also applied to the relativistic Dirac form factor F1p of the proton. In such a non-trivial case, the Maclaurin development might not exist for the radial density, rendering the determination from the proposed method extremely important.

Study on the rational construction methods and mechanical properties of composite beams in transverse negative bending moment zones

Study on the rational construction methods and mechanical properties of composite beams in transverse negative bending moment zones

Negative first moment of quadratic twists of L-functions

Negative first moment of quadratic twists of L-functions

Experimental Research on Flexural Behavior of the Staggered Joint Type Negative Moment Zone of UHPC Waffle Bridge Decks

Experimental Research on Flexural Behavior of the Staggered Joint Type Negative Moment Zone of UHPC Waffle Bridge Decks

RC T-beams with flexural strengthening in the negative moment region under different configurations of NSM CFRP rods

RC T-beams with flexural strengthening in the negative moment region under different configurations of NSM CFRP rods

Experimental Study on Flexural Behaviour of Prefabricated Steel-Concrete Composite I-Beams Under Negative Bending Moment: Comparative Study.

The issues of numerous steel beam components and the tendency for deck cracking under negative bending moment zones have long been challenges faced by traditional composite I-beams with flat steel webs. This study introduces an optimized approach by modifying the structural design and material selection, specifically substituting flat steel webs with corrugated steel webs and using ultra-high-performance concrete for the deck in the negative bending moment zone. Three sets of model tests were conducted to compare and investigate the influence of deck material and web forms on the bending and crack resistance of steel-concrete composite I-beams under a negative bending moment zone. The findings indicate that, compared to a conventional steel-normal concrete composite I-beam, incorporating ultra-high performance concrete into the negative bending zone enhances the cracking load by 98%, resulting in finer and denser cracks, and improves the ultimate bearing capacity by approximately 10%. In comparison to the composite I-beam with flat steel webs, the longitudinal stiffness of the composite I-beam with corrugated steel webs is smaller, which can further enhance the bridge deck's resistance to cracking in the negative bending moment zone, and maximize the steel-strengthening effect of the lower flange of the steel I-beam. Based on the findings of this study, it is recommended to use steel ultra-high-performance concrete composite I-beams with corrugated steel webs due to their superior crack resistance, bending strength, and efficient material utilization.

A Numerical and Theoretical Investigation of the Flexural Behavior of Steel–Ultra-High-Performance Concrete Composite Slabs

The steel–Ultra-High-Performance concrete (UHPC) composite slab is a new type of structure made of steel and UHPC connected by pegs, and its flexural mechanical properties and related design methods need to be further investigated. Firstly, a detailed numerical model of the steel UHPC composite slab is established and validated based on previous flexural behavior experimental research. Secondly, the flexural failure mechanisms of steel–UHPC composite slabs are clarified through finite element analysis. Under positive bending moments, when the degree of shear connection is lower than 100%, the ultimate load capacity of the composite slabs is determined by the shear capacity of the pegs. On the contrary, there are no significant changes in the load-carrying capacity of all the specimens, but there is a slight increase in stiffness. Under negative bending moments, the load-bearing capacity, stiffness, and crack resistance of the composite slab are improved as the degree of shear connection and reinforcement ratio increase. Finally, the method used to calculate the flexural capacity of steel–UHPC composite plates under positive and negative bending moments with high accuracy is proposed based on the analytical results. This paper provides a theoretical basis for the design of flexural performance of steel–UHPC composite slab.

Analysis of crack development law and calculation of crack width in the negative moment zone of externally inverted U‐shaped steel concrete composite beams

AbstractIn order to study the factors that affect the crack width, cracking mechanism, and development laws of the U‐shaped steel concrete composite (USCC) beam, and to propose a crack width calculation formula suitable for this new type of composite beam, cracking tests were conducted on four simply supported beam specimens. These specimens, which featured different steel beam forms, shear connectors, and longitudinal reinforcement arrangements, were all subjected to negative bending moments. Research has shown that USCC beams and H‐shaped steel concrete composite (HSCC) beams exhibited basically consistent crack width‐load relationships. In the early stage of the experiment, the crack width of the specimen exhibits an approximately linear relationship with the load, while in the late stage of the experiment, the crack width rapidly increases. In addition, the crack width of the USCC beam specimen developed faster than that of the HSCC beam. The experimental phenomenon shows that whether it is an USCC beam or a HSCC beam, the distribution of crack width along the concrete slab width is uneven, and this non‐uniformity is more obvious outside the beam width range. The centralized arrangement of longitudinal bars will exacerbate the non‐uniformity of crack width distribution, and the overall crack width is greater than that of specimens with uniformly arranged longitudinal bars. In addition, the effectiveness of channel shear connectors in controlling crack propagation is better than that of shear studs, and the slip at the interface between the concrete slab and the steel beam of the specimen using shear studs is greater than that of the specimen using channel shear connectors when the load is large. Based on the experimental results and formulas in the “Design Standards for Steel Structures” and the “Design Specifications for Concrete Structures,” a formula for calculating the crack width of USCC beams is proposed, and the coefficients in the current specifications have been corrected. The calculated crack width is in good agreement with the experimental value, which can provide a reference for calculating the crack width of this type of composite beam.

Investigation of shear bearing capacity of UHPC-NC connection structures in the negative bending moment zone of assembled beam bridges

Investigation of shear bearing capacity of UHPC-NC connection structures in the negative bending moment zone of assembled beam bridges

Comparative study on collapse behavior of modular steel buildings: Experiment and analysis

Comparative study on collapse behavior of modular steel buildings: Experiment and analysis