Collapse Analysis Research Articles

Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers

Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers

Characterisation and collapse analysis of composite egg-shaped pressure housings: experimental and numerical insights

ABSTRACT This study examined the collapse performance of composite egg-shaped pressure housings made of carbon fiber reinforced plastic (CFRP) layers and a nylon liner, fabricated using filament winding and 3D printing. Two types of housings—nylon and composite—were designed, fabricated, tested, and analyzed, with experimental results aligning with numerical predictions. The composite housings had an average ultimate strength of 5.98 MPa, 6.10 times greater than the nylon housings. Matrix compression damage was observed in the CFRP layer before reaching the ultimate strength, starting from the innermost CFRP layer. The composite housings outperformed other materials, showing a performance ratio 1.95 times higher than nylon, 2.75 times higher than resin, 1.31 times higher than Q235 mild steel, and 1.17 times higher than 304 stainless steel. These findings offer valuable insights for designing composite pressure housings and preventing collapse, highlighting their potential for deep-sea submersibles.

Numerical investigation on degradation mechanism of reinforced concrete structures under close-in explosion

In current practice, the analysis of progressive collapse in building structures widely employs the alternate load path method. However, there are very few collapse tests that can be utilized under blast loads, especially for investigating the degradation mechanism of progressive collapse resistance in post-blast building structures. In this study, the degradation mechanisms and methods for damage assessment of reinforced concrete structures under blast loads were investigated through numerical analysis. A substructure model derived from explosion loads based on a drop-hammer testing machine was validated by comparing with test results, and the established model accurately captured three typical failure modes in the substructure columns and confirmed the axial tensile effects of the columns on the adjacent components. A substructure damage assessment method was used to assess the degree of damage in a 5-story reinforced concrete frame structure under different explosion scenarios. The results show that the degree of damage distribution of the reinforced concrete frame structure exhibited an S-shaped distribution under corner column blast scenarios while an arch-shaped distribution was observed for middle column blast scenarios. Furthermore, empirical formulas based on the explosive mass and distance ( M- R) curves were established. These empirical formulas can help to rapidly predict the damage levels of RC frame structures for a given explosion scenario within a certain scope.

Failure analysis of time-delayed collapse triggered by time-dependent fracturing in a deep TBM tunnel

Failure analysis of time-delayed collapse triggered by time-dependent fracturing in a deep TBM tunnel

Calculation of steel frames in single-storey industrial buildings for progressive collapse by the quasi-static method

Introduction. According to the legislation of the Russian Federation and the current regulatory documentation, when designing buildings and structures of high consequences, it is necessary to make calculations for a progressive collapse caused by an emergency situation. There are four methods of analyzing buildings and structures for progressive collapse: linear-elastic static (quasi-static) method; nonlinear static method; linear-elastic dynamic method; and nonlinear dynamic method. A comprehensive analysis procedure with the use of all four methods is considered to be most effective, but such a comprehensive analysis requires additional work of the design engineer, therefore it is of practical importance to use one of the analysis methods mentioned above. This article describes the peculiarities of calculating metal structures for progressive collapse using the quasi-static method.Materials and methods. A compartment of an industrial building of high consequences class was taken as the object under study. The static calculation of the spatial scheme and the constructive calculation of the frame elements were performed in the Lira 10.12 program. Within the object under the study, we analyzed three options for the transition from the primary design scheme to the secondary one. In addition, we considered two more options that do not imply the removal of load-bearing elements from the design scheme after their failure.Results. Despite the fact that, when checking the selected columns for progressive collapse, we obtained ambiguous results for complete movements of nodes adjacent to the lower ends of the columns being removed (loosened) as a result of special impact, and some elements were not checked for design combination of forces, this calculation scheme should be considered resistant to progressive collapse.Discussion and conclusions. The calculation options used for progressive collapse analysis by the quasi-static method, when checked for design combination of forces, have shown identical results. The difference between the calculation options based on removing parts of the elements in which their operation fails, and the options based on unbinding these elements, has been about 2-3%.

Macro joint model for progressive collapse analysis of L-shaped CFST column frames

In this study, a macro joint model was developed to evaluate the progressive collapse resistance of L-shaped columns composed of concrete-filled steel tube (L-CFST) frames, accounting for joint performance. The methods used to calculate the spring stiffness in each part of the macro joint model were derived using the component method and the deformation coordination principle. Additionally, an L-CFST frame model consisting of fibre beam elements and macro joint models was created. For frame models with different parameters, the dynamic response under column removal was analysed; these parameters included the loading condition, connection type, the location of failed columns, the height and number of floors and the span–depth ratio of the steel beams. The macro joint model was found to have high accuracy in predicting progressive collapse resistance. The L-CFST column frames with novel side-plate reinforced connections fully exploited the catenary mechanism and Vierendeel action. All the variables affected the vertical displacement at the position of the failed columns, with the span–depth ratio having the most significant impact.

Catenary mechanism in steel columns under extreme lateral loading: A basis for building progressive collapse analysis

Catenary mechanism in steel columns under extreme lateral loading: A basis for building progressive collapse analysis

Physically-based collapse failure criteria in progressive collapse analyses of random-parameter multi-story RC structures subjected to column removal scenarios

Physically-based collapse failure criteria in progressive collapse analyses of random-parameter multi-story RC structures subjected to column removal scenarios

Dynamic sensitive failure mode in the progressive collapse of RC structures subjected to column removal scenarios

Dynamic sensitive failure mode in the progressive collapse of RC structures subjected to column removal scenarios

Generalized analysis of a dust collapse in effective loop quantum gravity: Fate of shocks and covariance

Generalized analysis of a dust collapse in effective loop quantum gravity: Fate of shocks and covariance

Robustness analysis of dynamic progressive collapse of precast concrete beam–column assemblies using dry connections under uniformly distributed load

Robustness analysis of dynamic progressive collapse of precast concrete beam–column assemblies using dry connections under uniformly distributed load

Study on field and numerical analysis of karst collapse as railway hazard

The vulnerability of karst ecosystems and the weak mechanical performance of caves pose hidden risks in railways, leading to increased karst collapses. To analyse karst collapse as a railway hazard, the Beijing–Guangzhou railway line in China was selected to identify karst features, using the multi-source frequency domain method because of its operational advantages. Abaqus was also used to numerically analyse the factors (dynamic loading, groundwater fluctuations, over-burden thickness) affecting the collapse mechanism. The study reveals diverse stratigraphy, transitioning from a Quaternary layer to stable rock formations. A notable finding is that the presence of a karst cavity in the railway embankment significantly increases the vertical dynamic displacements, particularly within the soil layer, by 72%, highlighting the significant impact of karst sections on soil dynamics. The study also reveals that due to the groundwater table fluctuations from the subsoil surface to the subgrade surface, the maximum displacement increases by 73% in the subgrade section of the railway embankment. The authors consider soil overburden thickness to validate confirmation of reliability through field data and theoretical study. The findings offer crucial insights for managing karst hazards, enhancing railway safety and ensuring durable infrastructure in challenging geological conditions.

Coupling effect analysis of dam break flood spread and building collapse based on numerical simulation

Coupling effect analysis of dam break flood spread and building collapse based on numerical simulation

Progressive Collapse Analysis of G+10 RCC Building

This study important of the progressive collapse that final damage of the structure is not similar as the initial collapse of structure. The key parameters used story displacement in eleven-storey building of regular shape that has modelled and analyzed by the ETABS 2018 software by using the Indian standard codes. Then for the calculation of progressive collapse we use U.S General Service Administration (GSA 2016) guidelines. The demand capacity ratio (DCR) values of the neighboring member are taken into account after the damage the DCR values for regular structure must be with in (2). In this study the progressive collapse is considered in three different cases that is at corner, interior and at exterior columns.

Generalisation of the yield stress measurement in three point bending collapse tests: application to 3D printed flax fibre reinforced hydrogels

This paper describes the extrusion pressure's effect on composite hydrogel inks' filaments subjected to three point bending collapse tests. The composite considered in this work consists of an alginate-poloxamer hydrogel reinforced with flax fibres. Increased extrusion pressure resulted in more asymmetrical filaments between the support pillars. Furthermore, the material and printing conditions used in the present study led to the production of curved specimens. These two characteristics implicitly limit the validity of the yield stress equations commonly used in open literature. Therefore, a new system of equations was derived for the case of asymmetrical and curved filaments. A post-processing method was also created to obtain the properties required to evaluate this yield stress. This new equation was then implemented to identify the strength of failed hydrogels without flax fibre reinforcement. A statistical analysis showed this new equation's significance, which yielded statistically higher (i.e. 1.15 times larger) strength values compared to the numbers obtained with the open literature equations. At larger extrusion pressures, longer periods were needed for the material to converge towards its final shape. Larger extrusion pressure values led to lower yield stresses within the composite hydrogel filament: a 5 kPa increase in extrusion pressure lowered the yield stress by 19%. In comparison, a 15 kPa increase led to a 29% decrease in the yield stress. Overall this study provides guidelines to standardize three point bending collapse tests and analysis comparison between different materials.

Blast-Induced Progressive Collapse Analysis: Accounting for Initial Conditions and Damage

The paper presents the progressive collapse analysis of structures, focusing on the impact of the initial conditions (particularly initial velocity) and the damage. It proposes a method that calculates the residual axial load capacity and damage of columns based on their strain profile and considers the effects of multiple blast locations. The methodology involves the conventional design of a three-story moment-resisting frame, selecting blast parameters, calculating blast pressures, and performing structural and progressive collapse analyses. The findings reveal that the Alternate Load Path Method (APM) overestimates the capacity compared to a benchmark blast–structure interaction analysis, especially when unsuitable initial conditions and damage properties are used. To address this limitation, the paper concludes the recommendations for incorporating appropriate initial conditions and damage considerations for a relatively accurate progressive collapse analysis.

Stochastic stability of random stacking of blocks

Stochastic stability of random stacking of blocks

Analysis of the progressive collapse of a parking garage concrete structure due to punching shear

Analysis of the progressive collapse of a parking garage concrete structure due to punching shear

Investigation on bending collapse behavior of similar and dissimilar Aluminum-Steel hat-section sandwich beams jointed by structural adhesive: An experimental, numerical and theoretical study

A significant feature about the application of adhesive joints in various structures is their ability to join dissimilar materials, thus effectively maintaining the structural integrity regardless varying loads. In this paper, the bending collapse behavior of adhesively bonded hat section sandwich beam (HSSB) structures with using of aluminum and steel were investigated. Four configurations of HSSB with different materials for the upper hat beam and lower plate were subjected to quasi-static three-point bending tests as part of the experimental investigation. In comparing the specific absorbed energy (SEA) of the beams, a sample of a hat section sandwich beam with a steel upper hat and an aluminum lower plate had a higher SEA value despite the load-displacement and bending collapse behavior similar to the hat section sandwich beam with a steel upper hat and a steel lower plate. subsequently, a finite element model was developed for bending collapse analysis and a theoretical prediction based on the Kecman model was presented to investigate the hinge moment on HSSB. Based on this, the findings of the numerical study and the predicted theoretical model were in good agreement with the experimental results. The effect of adhesive thickness, the identical mass, and the thickness of the upper hat and lower plate were examined for the purpose of performing an in-depth analysis of the influencing parameters in HSSB structures.

Wind-induced collapse mode and mechanism of super-large hyperbolic steel reticulated shell cooling tower with stiffening rings

Wind-induced collapse mode and mechanism of super-large hyperbolic steel reticulated shell cooling tower with stiffening rings