Damage Analysis Of Structures Research Articles

Geomorphological characterization, remote sensing monitoring, and modeling of a slow-moving landslide in Alcoy (Southern Spain)

In the present paper, an active landslide located to the southeast of the urban area of Alcoy (Alicante, Spain) is analysed. This landslide affects the N-340 road, as well as an area in which some industrial buildings dated from the fifteenth century and catalogued as Places of Cultural Interest are placed. This region is characterised by the existence of a steep relief composed of materials from the Miocene to the present, on which many gravitational movements are developed. The displacements have been analysed using high-resolution spotlight mode SAR images captured by the Spanish SAR satellite PAZ (which operates at X-band), which were processed by advanced differential SAR Interferometry (A-DInSAR). The behaviour of the instability has been determined using InSAR-derived time series displacement maps. Additionally, the study has been completed with a detailed geomorphological mapping at 1:2000 scale and an analysis of structural damage carried out in situ. The landslide was modelled in 3D, from a deterministic and probabilistic point of view, confirming the global instability of the area and the relationship of the landslide with rainfall and the construction of a new road. The integration of all this information obtained and its subsequent analysis has made possible to precisely define the extension of the instability, its kinematics, and to identify the main triggering factors. This information will be crucial for the proper management of this landslide by the local authorities.

Typhoon Damage Analysis of Typical Vulnerable Structures

Typhoon, as one of the most devastating natural hazards, has brought billions of property losses and threaten the safety of people around the world, and meanwhile, damage and collapse of various urban structures are the main components of direct losses caused by typhoon. Therefore, the review focus on the introduction on the impact and poster researches about three kinds of typhoon action, external wind pressure, internal wind pressure and wind-borne debris, on the structures at first, and then summarize the failure modes for three kinds of vulnerable structures, including bungalows, light steel industrial buildings and advertisement boards, respectively. Based on the data and field investigations on several severe or super typhoon, the failure modes of those structure start with the places where the elements are lack of potent connection and integrality, such as enclosure members, or the place where the stress concentration appears. This paper is looking forward to giving a assisting the engineers and scientists to improve the typhoon resistance measure or regulate the design of structures to prevent or alleviate the property loss and life security in typhoon in the field of structural analysis. This paper gives the summary on failure mechanism of vulnerable structures, and recommend the reinforcement trend on this field of structures.

Inverse Analysis of Structural Damage Based on the Modal Kinetic and Strain Energies with the Novel Oppositional Unified Particle Swarm Gradient-Based Optimizer

Structural damage inspection is a key structural engineering technique that strives for ensuring structural safety. In this regard, one of the major intelligent approaches is the inverse analysis of structural damage using evolutionary computation. By considering the recent advances in this field, an efficient hybrid objective function that combines the global modal kinetic and modal strain energies is introduced. The newly developed objective function aims to extract maximum dynamic information from the structure and overcome noisy conditions. Moreover, the original methods are usually vulnerable to the associated high multimodality and uncertainty of the inverse problem. Therefore, the oppositional learning (OL) for population initialization and convergence acceleration is first adopted. Thereafter, the unified particle swarm algorithm (UPSO) mechanism is combined with another newly developed algorithm, the gradient-based optimizer (GBO). The new algorithm, called the oppositional unified particle swarm gradient-based optimizer (OL-UPSGBO), with the convergence acceleration feature of (OL), enhances balanced exploration-exploitation of UPSO, and the local escaping operator of GBO is designed to specifically deal with the complex inverse analysis of structural damage problems. To authenticate the performance of the OL-UPSGBO, the complex benchmark set of CEC 2017 is adopted to compare the OL-UPSGBO with several original metaheuristics. Furthermore, the developed approach for structural damage identification is tested using several damage scenarios in a multi-story frame structure. Results show that the developed approach shows superior performance and robust behavior when tackling the inverse analysis of structural damage.

Investigation on bearing behavior of thin-walled bulge formed joint based on acoustic emission characteristic analysis

The truss structure is widely used, and the joints are its key component, which have a great impact on the structure function and safety. In this paper, bearing characteristics and failure process of a new type thin-walled bulge formed joint are investigated. Firstly, the acoustic emission (AE) test and stress test are carried out, and the distribution law of the AE activities of the thin-walled bulge formed joint is studied based on the parameter characteristics and location characteristics of the signal in the AE test. Then, to further analyze the variation law of the AE energy parameters and the plastic strain energy density, the results of AE test, stress test and the FEM are compared in terms of energy evolution, which shows the consistency of the structural microscopic energy release and the macroscopic stress change of the thin-walled joint. Finally, the location and evolution law of the failure process of thin-walled bulge formed joint in the bearing process are discussed, which also provides reference for the identification and analysis of other thin-walled structural damage.

Fractal Analysis of Tunnel Structural Damage Caused by High-Temperature and Explosion Impact

The tunnel is one of the most important components in modern underground engineering. Due to long and narrow shape constraints, it very easily results in large-scale fire and explosion when deflagration is caused by the accidents of vehicles that transport dangerous goods in the tunnel. Previously, the studies on the damage to tunnel lining caused by high-temperature impacts in these kinds of disasters were often limited to a discussion of only one influencing factor, either fire or explosion, but they rarely considered the two factors simultaneously. In this work, the damage properties of full-size tunnel lining induced by high temperature and impact were evaluated, and the concrete samples from the whole lining arch were selected for CT scanning. The improved differential box-counting method was used for the fractal analysis of the CT images to obtain the damage-distribution properties of the tunnel lining structure under the two coupled influencing factors: the high temperature caused by fire, and the impact caused by deflagration.

Damage analysis of typical structures of aircraft under high-velocity fragments impact

In this paper, by establishing a fragmented field of a prefabricated fragment warhead and simulating the intersection of the aircraft and the fragment field under dynamic conditions, the determination of the distribution of the vulnerable parts of a specific aircraft is realized. On this basis, the structural characteristic test pieces of the vulnerable parts were tested with the high-velocity impact experiments based on the two-stage light-gas gun. Based on the FEM-SPH self-adaptive method, a numerical simulation model with a high reduction degree was established. Combined with the experimental results, the damage mode of high-velocity prefabricated spherical fragments to typical vulnerable structures, especially the characteristics of secondary damage caused by debris clouds were studied. This paper verified the feasibility of methods for the vulnerable structure distribution of the aircraft by combing the shooting-line method and the Monte Carlo method. The FEM-SPH adaptive method simulates the damage mode and secondary damage caused by debris clouds on vulnerable aircraft structures. The study in this paper can be severed as an analysis tool in specific aircraft design and damage mode analysis under different threat sources.

Concrete damage analysis based on higher-order beam theories using fracture energy regularization

This paper presents the numerical damage analysis of concrete structures using higher-order beam theories based on Carrera Unified Formulation (CUF). The concrete constitutive relation is modeled using continuum damage mechanics based on a modified Mazars concrete damage model, in which both the tensile and compressive softening behaviors are regularized with classical fracture energy methodology. An expression is proposed to estimate the characteristic length in higher-order beam theories, to prevent mesh dependency. Both softening constitutive laws and fracture energy calculations are obtained according to Model Code 2010. To assess the efficiency of the proposed model, three classical benchmark quasi-static experiments are taken for validation. From the comparison between numerical and experimental results, the proposed CUF model using continuum damage mechanics can present 3D accuracy with low computational costs and reduce the mesh dependency.

Holistic determination of physical fracture toughness values and numerical parameters for delamination analysis considering multidirectional-interfaces

Delaminations are a concern for the structural integrity of fibre composite structures. The decisive material parameter for delaminations is fracture toughness. Structures usually have a multidirectional ply stacking. However, interface orientation dependant fracture toughness values and R-curve effects are neglected in numerical delamination analysis. This work investigates interface orientation specific fracture toughness values and considers R-curve effects in mode I to improve simulation accuracy. Therefore, mode I, mode II and mixed mode fracture toughness values of different interface ply orientations are determined experimentally and verified using numerical analysis of the characterisation specimens with cohesive zone modelling. In this way, an engineering methodology is provided for the experimental characterisation and comprehensive numerical modelling of delaminations in mesoscale progressive damage analysis of multidirectional composite structures. In addition, a full parameter set for the simulation of four different interfaces of M21-T700GC prepreg material is given. It can be shown that the use of standard 0°//0°-values leads to very conservative results. The use of interface specific values increases the accuracy. Ultrasonic scans of the DCB specimens are used to compare the crack front shapes for validation. Not only the load displacement curves of the characterisation specimens are well captured, but also the crack front shapes. This demonstrates that by smearing the microscale effects, the material behaviour can be captured phenomenologically correct by mesoscale modelling suitable for industrial use.

Stochastic, probabilistic and reliability analyses of internally-pressurised filament wound composite tubes using artificial neural network metamodels

Progressive damage analysis of composite structures in the presence of uncertainties is a computationally-expensive and highly-complex process. This work tackles these issues by developing efficient finite element (FE)-based surrogate models that are constructed with artificial neural network (ANN) models and design of experiment (DOE) methods. The proposed framework for building surrogate models (metamodels) can capture various multi-scale uncertainties. In addition, to alleviate the computational burden in non-deterministic analyses, a novel strategy is proposed using the Plackett-Burman method to determine sources of uncertainties that have significant impacts in scattering the response. The response surface methodology (RSM), along with FE analysis, is used to create datasets. The RSM and ANN metamodels are constructed by using these datasets. Key results show that for complex models, ANN metamodels have more accuracy than RSM ones. The surrogate models are used for stochastic, probabilistic and reliability analysis of filament wound composite tubes. As a result, this multi-scale surrogate-based framework significantly decreases the computational time and cost of the analyses. Reliability analysis demonstrates that the statistical correlation between ply properties is significant, and it must be considered for an accurate evaluation.

Structural damage analysis of CRTS Ⅱ slab track with various interface models under temperature combinations

Under temperature loading, the contact interface of cement asphalt mortar (CAM) layer and T-shaped joint are two vulnerable components of China Railway Track System type II (CRTS II) slab ballastless track. The purpose of this study is to develop six types of three-dimensional (3D) nonlinear finite element (FE) models for investigating the thermal behaviors of CAM and T-shaped joint under various temperature conditions. This was achieved by modelling CAM and T-shaped joint using cohesive zone model (CZM) and concrete damaged plasticity model (CDPM), respectively. Using five CRTS II slab tracks on a simple-supported box girder as a case study, the displacement and stress responses of the track structure were investigated and compared under six cases of overall temperatures and temperature gradients, respectively. Results show that CZM and CDPM have the capabilities of simulating the interlaminar debonding and damage behavior development in CRTS II track under various temperatures conditions. The combination of CZM and CDPM could provide the worst damage scenarios, and the CDPM of the joint could significantly reduce the structure responses. In addition, the increase of overall temperature together with temperature gradient could significantly increase the deformation and stress in CAM layer, and the influence of the magnitude of overall temperature is more obvious than that of temperature gradient.

A Hybrid Local/Nonlocal Continuum Mechanics Modeling of Damage and Fracture in Concrete Structure at High Temperatures

This paper proposes a hybrid peridynamic and classical continuum mechanical model for the high-temperature damage and fracture analysis of concrete structures. In this model, we introduce the thermal expansion into peridynamics and then couple it with the thermoelasticity based on the Morphing method. In addition, a thermomechanical constitutive model of peridynamic bond is presented inspired by the classic Mazars model for the quasi-brittle damage evolution of concrete structures under high-temperature conditions. The validity and effectiveness of the proposed model are verified through two-dimensional numerical examples, in which the influence of temperature on the damage behavior of concrete structures is investigated. Furthermore, the thermal effects on the fracture path of concrete structures are analyzed by numerical results.

Bow structure damage analysis for hybrid coir-glass fiber composite fishing boat hull subjected to front collision load

Abstract Hybridization of natural and synthetic fibers has the ability to improve composite performance. It means that the combination of natural fibers such as coir, jute, bamboo, and sisal with synthetic or glass fiber can broaden the role of the composite material, especially for structural application. This study developed a finite element simulation to investigate the damage to the bow structure of the fishing boat hull, which was produced using hybrid coir-glass fiber composite (HCGFRP) material subjected to front collision load. The experimental measurement was conducted to determine the mechanical properties of four hybrid composite laminates defined based on the differences in their layers number, fiber types, and orientation angle. Moreover, a numerical simulation model was applied to the traditional fishing boat colliding with fishery harbor quay, and the scenario was defined by varying the boat speed and the types of laminates adopted on the hull structure. The results showed the damage level for the bow structure of the HCGFRP boat due to the collision accidents, while the numerical findings are expected to be used as the basic knowledge in applying the hybrid coir-glass fiber laminates composite as an alternative hull construction material.

A Comprehensive Analysis of Light Weight Steel Structure and Wind Load

Review to hot-rolled steel structures, cold-formed steel structures are susceptible to extreme winds because of the light weight of the building and its components. Many modern cold-formed steel structures have sustained significant structural damage ranging from loss of cladding to complete collapse in recent cyclones. This article first provides Review some real damage cases for light steel structures induced by the high winds. After that, the paper reviews research on the damage analysis and evaluation of light steel structures caused by strong winds, which include connection failure, fatigue failure, purlin buckling, and primary frame component instability problems. Moreover, this review will mention some applications of structure damage assessment methods in this area, such as vulnerability analysis and performance-based theory, etc.

Traffic-based quantitative risk analysis of structural fire damage to roadway tunnel linings

This paper demonstrates a quantitative risk analysis (QRA) approach of fire-induced damage to the reinforced concrete linings in roadway tunnels. Large fire events associated with buses and heavy goods vehicles are the focus of this study because their impact on the tunnel linings is structurally significant versus fires from smaller vehicles. The proposed approach accounts for stochastic variations of fire severity and frequency (based on traffic volume and the percentage breakdown by vehicle type) as well as the consequences (structural and economic) of thermal exposure to tunnel linings. The probabilistic distribution of fire size is developed using available weight-in-motion data, and combustible vehicle mass is correlated with the peak heat release rate using published test data and forensic reports. The heat transfer from the vehicle fire to the tunnel linings was modelled by a fast-running computational tool that was previously developed by the authors. Fire-induced damage to the tunnel linings is categorized into three levels of progressive strength reduction and cracking potential. Economic impacts are calculated in terms of estimated repair costs. The proposed approach enables informed decision making for the design or renovation of tunnel fire protection by quantifying the loss potential for severe fire hazards in a given tunnel.

Seismic performance design of energy-dissipated structure system based on damage control and time-varying damping ratio

The installation of energy dissipation devices on building structures can significantly reduce seismic damage. A brief review of first, second and third generation performance-based seismic design (PBSD) theories, and a comparative analysis of existing PBSD methods for energy-dissipated structure systems confirms that design methods based on force, displacement, and energy are inadequate. A more comprehensive approach is the damage-based design method, which can evaluate the seismic performance of structures. However, due to the lack of an analytical relationship between the additional equivalent damping ratio (AEDR) of dampers and the damage degree of the main structure, the current performance design method can only predict the expected damage via an iterative adjustment analysis of damper's design parameters. The authors addressed this problem by analyzing the damage mechanism of the energy-dissipated structure system's core area from the perspective of energy dissipation. It is established an analytical relationship between the AEDR and the damage index of the main structure with dampers via a damage model based on the energy difference ratio and the time-varying AEDR calculation of dampers subjected to ground motions. With this new approach to seismic vulnerability analysis, the performance design flow of the seismic structure system is based on damage control. A case study verifies the accuracy of the damage-degree based AEDR calculation. The proposed damage-based method effectively controls the damage degree of the main structure to the expected damage target. This method is compatible with the displacement-based design method, and which also enriches the research contents of structural seismic design and damage analysis in the third generation PBSD.

Relationship between damage and structural vulnerability in historical heritage: Case study of San Fernando de Bocachica Fort, Cartagena de Indias

The restoration process for historical heritage is complex and consists of several steps. In the professional field, the evaluation of the structural vulnerability of a historical monument often does not include an evaluation of its previous damage. It is important to understand the degradation phenomena to properly interpret the results of structural analysis and make better decisions for the maintenance and structural reinforcement.In the present study, a seismic vulnerability assessment with a linear dynamic analysis was carried out at San Fernando de Bocachica Fort. In addition, structural damage and deterioration types were categorized and mapped. Finally, a comparison between structure stress distribution and damage analysis is proposed. A marked relationship between structural overstress and structural decay is noted, which makes this methodology a valuable tool that could be implemented for the more effective maintenance of historical heritage around the world. The fort presents severe deterioration, highlighting the need for immediate intervention to preserve its aesthetic and structural stability.

Stochastic Analysis of Short-Term Structural Responses and Fatigue Damages of A Submerged Tension Leg Platform Wind Turbine in Wind and Waves

Stochastic Analysis of Short-Term Structural Responses and Fatigue Damages of A Submerged Tension Leg Platform Wind Turbine in Wind and Waves

Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

Automated manufacturing defects are new types of composite structure defects induced during fiber deposition by robots. Fiber tow gap is one of the most probable types of defects observed in the Automated Fiber Placement (AFP) technique. This defect can affect the structural integrity of structures by reducing structural strength and stiffness. The effect of this defect on the mechanical response of the composite laminates has been investigated experimentally in the literature. However, there is still no efficient numerical/analytical method for damage assessment of composite structures with distributed induced gaps manufactured by the AFP technique. The present paper aims to develop the Induced Defect Layer Method (IDLM), a new robust meso-macro model for damage analysis of the composite laminates with gaps. In this method, a geometrical parameter, Gap Percentage (GP), is implemented to incorporate the effect of induced-gaps in the elastic, inelastic, and softening behavior at the material points. Thus, while the plasticity and failure of the resin pockets in conjunction with intralaminar composite damages can be evaluated by this method, the defective areas are not required to be defined as resin elements in the Finite Element (FE) models. It can also be applied for any arbitrary distributions of the defects in the multi-layer composite structures, making it a powerful tool for continuum damage analysis of large composite structures. Results indicate that the proposed method can consider the effect of gaps in both elastic and inelastic behavior of the composite laminate with defects. It also provides good agreement with the experimental results.

Analysis of Bone Microarchitectural Changes and Structural Damage in Sickle Cell Disease-Induced Avascular Necrosis Using Raman Spectroscopy: Is there potential for medical management?

ObjectivesBone failure due to avascular necrosis (AVN) is a complex pathological phenomenon. Analysis of molecular changes in the bone matrix may help to shed light on the disease process and guide management. This study aimed to explore changes in bone quality and structural damage caused by sickle cell disease (SCD)-induced AVN using Raman spectroscopy.MethodsA total of 10 necrotic femoral heads were obtained from seven SCD patients who underwent total hip replacements. The femoral heads were cut in half and scanned using Raman spectroscopy in correlation with preoperative magnetic resonance imaging to identify necrotic and healthy control areas. Subsequently, samples were examined to determine changes in bone mineralisation, crystallinity, carbonate content, collagen cross-linking and mineral and collagen fibril orientation.ResultsSignificant changes were observed in bone mineral content, mineral-to-organic content and collagen fibril orientation in necrotic compared to control areas (P ≤0.050).ConclusionThe necrotic samples displayed severe structural damage and loss of mineral and organic contents. Similar Raman signals have been reported in other metabolic bone diseases such as osteoporosis, thereby potentially supporting the use of medical treatment in AVN to promote bone quality.

Probabilistic seismic performance evaluation of composite frames with concrete-filled steel tube columns and buckling-restrained braces

The concrete-filled steel tube (CFT) composite frames using blind bolts and buckling-restrained braces (BRBs) have been studied with the development of building industrialization and energy dissipation technology. However, there has been no research so far on the probabilistic seismic fragility analysis for the blind-bolted end-plate CFT composite frames with BRBs (BRB-BECFT). Therefore, a total of 6-, 9-, 12- and 20-story BRB-BECFT prototype structures were designed based on the performance-based plastic design method. The results obtained from nonlinear static and dynamic analyses indicated that the four structures achieved predefined performance objectives in terms of story drift, joint rotation, and BRB ductility demand. Subsequently, fragility curves including non-collapse and collapse states were established to evaluate the behavior of the structure for a given intensity measure using the incremental dynamic analysis approach. Meanwhile, the geometric mean of spectral acceleration over a period range (Sa,avg) was selected as the intensity measure to assess the structural collapse capacity. Results showed that the adoption of Sa,avg can result in 32–42% lower data dispersion for the determination of collapse point, and simplification of the process of calculation of the collapse margin ratio of a structure. Furthermore, based on the combination of Sa,avg, residual story drift and BRB core plate strain, a framework of probabilistic seismic damage analysis of structures for combined damage evaluation at three levels of the system, subsystem, and component was summarized and conducted by the 6- and 12-story case study. This is practically useful to assess structural damage state after an earthquake because it could present more information on the probability distribution of various damage scenarios.