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The evidence of soil nonuniformity has been reported in several site investigation reports and is well-confirmed for any soil in general. However, studies related to the spatial soil variability of offshore ground are somewhat limited, and current design practices for monopile foundations also overlook the uncertainty of the offshore ground. This paper presents the probabilistic evaluation of the serviceability limit state of monopile foundations considering the spatial variability of offshore ground. The nonuniformity of the ground is modeled utilizing the site-specific undrained shear strength (su) as a stochastic variable, using a spatially correlated Gaussian random field. A hardening soil constitutive model is utilized in 3D finite element analysis of offshore ground, with a focus on parameter calibration. The reliability of the serviceability limit state is assessed based on the allowable load on the pile head. The stochastic behavior of the maximum bending moment and maximum shear force along the depth of the monopile is also investigated. Besides, the paper also highlights the importance of incorporating ground nonuniformity during the design process of a monopile foundation. [ABSTRACT FROM AUTHOR]

This paper presents a multibody model of the post-derailment dynamics of a railway vehicle and its impact with a derailment containment wall (DCW) built aside the line and demonstrates the use of the model in the context of the structural sizing of devices intended to mitigate derailment effects. With respect to existing multibody models of railway vehicle dynamics, the innovative features of this model are a new contact model capable to provide a plausible prediction of the derailment process despite a simple and computationally efficient formulation, and the model of the interaction between the derailed vehicle and the impacted derailment containment structure, the latter being described by a Finite Element Model. Results from the model are compared to an established multibody software for a non-derailment case, and then a comparison is performed with a measurement from a derailment experiment published in the scientific literature, finding in both cases satisfactory agreement. The model is then applied to analyse a derailment scenario caused by the sudden failure of an axle for a locomotive vehicle travelling at 300 km/h in a HS curve, deriving the peak values of the impact force and bending moment at the base of the derailment containment wall. [ABSTRACT FROM AUTHOR]

As basic structural components of the ship hull, stiffened plates suffer both thrust and shear loads while ships sail in rough sea environments. In order to guide the scaled model design effectively, the similarity law is investigated in this paper. The parameters that determine the nonlinear behaviour of the stiffened plate under compression and shear loading are defined and the nonlinear similarity method is improved. This method is applied to design a scaled model under combined bending and torsional moment, and the collapse test is conducted to research the collapse characteristics. The collapse behaviour of actual ship structures under combined loads predicted by the model test is compared with that obtained by the nonlinear finite element analysis. The good agreement represents the capability of the newly improved nonlinear similarity law. The present research provides a proper way to investigate the collapse characteristics of actual ship structures through a model test. [ABSTRACT FROM AUTHOR]

Axial forces are generated in the plates of ADAS-yielding dampers when subjected to lateral loading due to their boundary conditions. This on one hand can lead to an increase in strain level of the plates and accelerate the damage process, while on the other hand, the interaction of the bending moment with the tensile axial force leads to increasing strength, which is undesirable in the performance of ductile members. In this paper, a modified ADAS device (MADAS) is introduced to prevent undesirable interaction of axial forces, and its cyclic behavior is evaluated both experimentally and numerically. To this end, in the first step, two test specimens with different number of connection pins were prepared and subjected to cyclic loading in a rigid frame. Experimental and numerical results have shown that due to the removal of the constraint in the vertical direction, the level of forces produced by the damper is almost constant and the X-shaped plates have been able to tolerate significant number of cycles before crack initiation. Afterwards, the cyclic performance of ADAS and MADAS dampers was numerically compared individually and also when placed in the frame. Furthermore, in the frame equipped with ADAS damper, the increase in the level of forces produced by the damper led to the buckling of the braces, while the level of generated forces was totally in the expected range in the frame equipped with MADAS damper. [ABSTRACT FROM AUTHOR]

The monopile-friction wheel hybrid foundation withstands various loads in the marine environment, such as the vertical load (V) transmitted from the superstructure, horizontal loads (H) caused by wind or wave, torsional loads (T) caused by rotating structures. In this article, 1 g model tests are used to investigate the behavior of the monopile-friction wheel hybrid foundation under independent horizontal load (H) or torsional load (T), and combined loads (H-T) in sand soil, respectively. The failure envelopes of H-T loading plane are obtained from the measured load-displacement data with the simplified calculation equations presented as well. Finally, we also discuss quantitatively the influences of the pre-vertical loads, foundation geometry and loading eccentricity on the bearing capacity of the hybrid foundation via the three-dimensional finite element method. The results indicate that the displacement response of the hybrid foundation under independent loading is significantly different from that subjected to combined loads (H-T). The torsional bearing capacity of the hybrid foundation can be significantly improved by 6.6-33.34% under pre-horizontal load. The horizontal bearing capacity of the hybrid foundation decreases sharply after the pre-torsional load reaches a certain value, which decreases by about 20%. The presence of a friction wheel improves the torsional/bending moment distribution of pile shaft. [ABSTRACT FROM AUTHOR]

The need for smooth, gapless mechanisms that offer superior aerodynamic performance has been the prime mover for a wide range of studies on the morphing concepts from the early years of the twenty-first century. In light of the importance of novel analytic means for inspecting such structures, this article describes a comprehensive dynamic model for the flexural vibration of a special type of morphing structure known as fish bone active camber (FishBAC). In view of the shortcomings of previous models, the developed procedure considers the variable thickness of the central spine of FishBAC as well as the possibility of arbitrary truncations in its numerous partitions to offer more accurate results. A general idea is first proposed based on the assumptions of classical plate theory for such partitioned structures. The equations are derived using the energy method and the assumption of artificial springs to satisfy the continuity of shear force and bending moment along the connecting lines between partitions. A robust Rayleigh-Ritz method along with a set of fast-converging admissible functions is presented to solve the governing equations of motion. Combined with the power of Mathematica and validated by other analytic models and finite element codes, this technique can be used to deal with a plethora of similar systems while paving the path for the dynamic analysis of FishBAC built around various airfoils. [ABSTRACT FROM AUTHOR]

Curved panels are structural elements that form the skin of wings, fuselages and tail booms in aircraft. Buckling of these structures would adversely affect aircraft performance. Due to this, the problem of buckling has been extensively researched in the past. Most of the research has been restricted to the analysis of flat composite panels and analysis of curved panels through simplifications involving geometry, material properties and boundary conditions. The present study aims to develop an analytical solution that can predict the critical buckling load for a wider range of problems. An analytical solution was developed in order to obtain the critical buckling load for a doubly-curved composite laminate under compression, shear, moment or any combination of the three loads. The assumptions of the classical laminate plate theory were used in order to obtain the displacement fields as well as strains of the laminate. The energy method was employed in order to obtain the critical buckling load for various load cases. The values obtained through the analytical solution are compared to the critical buckling loads obtained through finite element analysis (FEA). The highest deviation of critical buckling load from FEA was calculated to be 16.55%. Variation of the critical buckling load with respect to the radius of curvature, boundary conditions and stacking sequence was analyzed. The developed solution was also found to be valid for cases when radii of curvatures are unequal as well as when the length and breadth of laminate are unequal. [ABSTRACT FROM AUTHOR]

Occurrence of progressive collapse events invariably leads to significant economic and human-life losses. Progressive collapse analysis and design of building structures have become a research hotspot worldwide. Existing studies have proved that development of extra load-carrying mechanisms could significantly improve the resistance of structures to progressive collapse. However, limited research has been conducted to quantitatively analyze these mechanisms. This study proposed a new and unified division method for mechanisms for resisting progressive collapse; furthermore, it provides a basis for their quantitative analysis. In addition, the progressive collapse behavior of a 1/3-scaled two-story, one-bay-by-two-bay reinforced concrete (beam–slab–column) frame with an edge column lost was experimentally investigated. Additionally, a 3 D solid finite element model was established and validated based on the test results. The effects of different extensive parameters, including ideal lateral constraints, slab thickness, and beam–slab interaction, on each resisting mechanism were quantitatively investigated. Finally, a new simple method for predicting the first peak load was proposed based on the contribution of each mechanism. The results from the simple method were in agreement with the simulation results of beam–slab–column structures. [ABSTRACT FROM AUTHOR]

Piles in soft soil supporting bridge abutments are often exposed to passive loading induced by adjacent bridge approach embankment. Several methods for analysis of passive piles have been developed, but the international design specifications do not recommend a specific method for the analysis of passive piles. Therefore, the applicability of existing empirical and analytical analysis (conventional) methods is examined by comparing their outputs with those of a validated finite element model (FEM) at various adjacent embankment stress levels, and construction times, soft clay thicknesses, and pile spacing to diameter ratios. Outputs of both conventional methods and FEM show that increasing the embankment stress, thickness of soft clay layer, and pile spacing to diameter ratio results in an increase in the lateral pile displacement, maximum bending moment, and lateral pressure, and vice-versa on increasing embankment construction time. The outputs of the conventional analysis methods are compared to the FEM outputs and are underestimated except for few cases. The conventional analysis methods may yield better predictions at pile diameter-to-spacing ratio equals 3–4 for a soil preloaded prior to pile construction to a degree of consolidation greater than 50%. [ABSTRACT FROM AUTHOR]

The injury conditions of the sitting position occupant inside the military equipment are highly related to the vertical impact environments. In this study, a detailed three-dimensional finite element (FE) model of pelvis-lumbar spine of seated human with nonlinear material property and strain failure criterion was developed and validated. A series of sinusoidal accelerations with a constant peak speed of 8 m/s and frequencies ranging from 10 Hz to 90 Hz were loaded on the FE model to investigate the injury conditions under different high loading rates. The results indicated that the injury patterns mainly include wedge fracture of the junction between lumbar spine and pelvis, and comminuted fracture of ischial tuberosity. The bending moment caused by the large angle deflection of pelvis under 10 Hz case (low rate) and the acting force caused by the excessive curvature of lumbar spine under 30 Hz–70 Hz cases (medium and high rate) cause the junction wedge fractured, while the high impact force under 30 Hz–50 Hz cases (medium rate) leads to comminuted fracture of the ischial tuberosity. The associated mechanism that the shorter the time interval between the peak of seat loading speed and the peak of hip muscle compression, the more serious dynamic responses of pelvis-lumbar spine is revealed for the first time. [ABSTRACT FROM AUTHOR]

In this study, a series of centrifuge tests are performed to investigate the ultimate lateral capacity of a pile group for offshore wind turbines. The validated Finite element models (FEMs) are established. The rotation center and the maximum bending moment occur at 9 D and 3 D of the pile length. A sensitivity study is performed by considering the soil parameters through numerical tests. The internal friction angle is the most influential factor by introducing 32% change in lateral capacity. The key factors of pile number, pile diameter, loading height, and pile spacing are investigated in the following parametric study. Increasing the pile number and the pile diameter is effective for enhancing the lateral capacity. In contrast, a larger eccentricity has a negative effect on the foundation stability. The failure mode of the pile group foundation tends to change from strain softening to strain hardening when the loading height reaches a threshold magnitude. The p-multiplier is calculated to demonstrate the shadowing effect in a pile group foundation. An optimal design method is proposed by integrating the pile number and the pile spacing factors. This study provides some instructions for the application of pile group foundations in the offshore wind industry. [ABSTRACT FROM AUTHOR]

Seismic vulnerability of speleothems may serve long-term seismic risk studies. For this reason, the seismic response of stalagmite is computed using a robust FEM model calibrated from free vibration records by Hilbert–Huang modal extraction. It is demonstrated that the stalagmite vibrations consist of pairs of closely coupled flexural natural modes with a negligible role of vertical excitations. The location of the breaking point of the stalagmite is a result of a balance between the overturning bending moment and variations of horizontal cross-sections with height. Safety margins are investigated, and the ultimate peak velocity of excitations equaling 3.4 mm/s is estimated. [ABSTRACT FROM AUTHOR]

The response of laterally loaded piles installed near the crest of clay slopes is analysed. Three-dimensional finite element analyses are presented for piles at various distances from a slope crest and for different pile shape. The results of these analyses are used to study the variation of the pile displacement, the bending moment of the pile and the soil resistance in relation to pile to slope distance and pile shape. The obtained results show that the proximity of slope significantly affects the lateral load capacity of the piles but not significantly when the piles are placed at 7D (where D is pile diameter) or greater from the slope crest. Furthermore, the lateral soil resistance on the ground surface for circular piles is larger than that for rectangular piles at the same lateral load in level ground. The decrease rate of lateral soil resistance on the ground surface for circular piles gets faster as the slope ratio and load level increase. [ABSTRACT FROM AUTHOR]

This paper reports a hybrid modular floating structure (HMFS) system preliminarily designed for mild marine environment. It is composed of a certain number of inner semi-sub modules and outermost box-type modules. The box-type modules are connected to adjacent semi-sub modules with hinges and additional Power Take-Off (PTO) damping systems. The hydrodynamic characteristics of several representative simplified serially connected HMFS systems under typical sea conditions are compared. The functions of the outermost module, the effects of different outermost module types and the expansibility of the HMFS system are emphatically analysed. The results indicate that compared with the outermost semi-sub module, the outermost box-type module is more effective in reducing the motion responses of inner semi-sub modules, connector forces and mooring forces. The additional PTO damping systems can produce substantial wave energy. The HMFS system shows good expansibility for mild sea zones. Abbreviations: HMFS, Hybrid Modular Floating Structure; VLFS, Very Large Floating Structure; RMFC, Rigid Module and Flexible Connector; MOB, Mobile Offshore Base; FEM, Finite Element Method; PTO, Power Take-Off; MFS, Modular Floating Structure; Ks, Pitch Elastic Stiffness; Kp, Pitch Damping Coefficient; DOF, Degree of Freedom; Fx, Horizontal Force of Connector; Fz, Vertical Shear Force of Connector; My, Pitch Bending Moment of Connector [ABSTRACT FROM AUTHOR]

The concept of pier-supported submerged floating tunnel (PSFT) is feasible if the water depth is within 100 m. In this study, semi-analytical solutions are proposed for determining the seismic responses of a tunnel tube in a PSFT subjected to vertical excitation. The tunnel tube consisting of tube segments and flexible joints is simplified as beam components connected through bending springs. The supporting system comprising bearings and piers is regarded as a series of discrete Kelvin elements. Seismic action is considered as the inertia force and hydrodynamic pressure is calculated by the Morison equation. The tunnel tube displacement is derived by the modal superposition method. On this basis, the semi-analytical solutions of the displacement and bending moment of the tunnel tube are deduced using the Runge–Kutta method. The finite element method is employed to examine the validity of the proposed solutions. Furthermore, the effects of the fluid, flexible joints, and damping ratio are discussed. The results show that the Froude–Klylov force can significantly reduce the response amplitude, and the hydrodynamic mass force can alter the response frequency under real seismic input motion. Flexible joints can adjust the bending moment distribution in the tunnel tube. With the adoption of flexible joints, the hogging moments at the bearings considerably decrease. The change in damping ratio also have substantial effects on the structural seismic response. [ABSTRACT FROM AUTHOR]

This study investigates the effects of near- and far-fault ground motion on the seismic behavior of historically inclined minarets. Inclined minarets built in Aksaray and Sivas, Turkey, are selected as numerical applications. The top of the Aksaray and Sivas minarets is 1.30 m and 1.23 out-of-plumb and the inclination values are 2.45° and 1.97°, respectively. Firstly, 3D finite element models of the minarets are created using solid elements by SAP2000 software and the numerical dynamic characteristics are determined numerically. 1992 Erzincan and 1999 Kocaeli earthquakes as near- and far-fault ground motion records are selected for the analyses. Maximum displacements, base bending moments, base shear forces, and principal stresses are determined using the finite element method. The results obtained for both earthquakes are compared with each other. It is clearly seen that near-fault ground motion has resulted in much larger response values for both minaret models when compared with far-fault ground motion and max stresses that occurred on the transition segments. [ABSTRACT FROM AUTHOR]

This paper presents the optimization of stacking sequence of composite laminate adherends in an adhesive single lap joint under bending moment in order to minimize the amount of maximum peel and shear stress of the adhesive layer. The effects of different assumptions on the equations of the stress and their results are presented. The adhesive single lap joint is modelled as an adherend-adhesive sandwich panel. The finite element method is used to verify the analytical method and the structure is modelled by ANSYS software version 14. The results of the analytical method and the finite element method are compared, and there was a good agreement between two methods. For the optimization part, the single-objective and multi-objective bees algorithm are used to search for the best and worst stacking sequence with and without permutation. The results of the optimization indicate that the maximum shear and peel stress highly depend on the extensional, coupling and bending stiffness in a way that in the optimum model, adherends have high and almost equal stiffness. In the worst models, there is a huge difference in the stiffness of the adherends causing destructive high stress in the thinner adherend. [ABSTRACT FROM AUTHOR]

The lateral deformation behaviour of inclined piles in calcareous sand is investigated with model testing and numerical analysis. A model pile is instrumented with quasi-distributed strain sensors and installed in calcareous sand with various inclination angles. The lateral deformation, bending moment and shear force of the pile are analysed by investigating the effect of the inclination angle and embedded depth. The experimental results of piles with inclination angles of −30°, 0° and 30° are analysed. A random finite element method (RFEM) is established to investigate the effect of the pile inclination. A single exponential function is used to characterize the spatial autocorrelation of soil parameters. A random field is obtained by the Cholesky method. The RFEM is verified with experimental results and used to further analyse the lateral deformation behaviour. The results indicate that both of the orthogonal maximum influence distances from the pile centre have a linear relationship with the pile inclination. A linear relationship between the maximum lateral deformation on the pile top and the pile inclination is proposed. The outcome of this study may be helpful for understanding the lateral deformation behaviour of piles in calcareous sand and designing inclined piles. [ABSTRACT FROM AUTHOR]

Of the 604,485 bridges in the United States, approximately 21% are culverts having a span of 6 m (20 ft) or greater. The load rating of typical bridges presents numerous challenges. Developing load ratings for non-typical structures, such as buried arch-shaped culverts is more complex because of the culverts' unique geometric configuration and their interaction with soil media. This paper proposes an alternative analytical method for load rating in-service reinforced concrete (RC) arch culverts that overcomes the limitations of the widely used elastic frame concept while being straightforward to implement. The proposed analytical method uses two-dimensional finite element models of the arch structure and surrounding soil media. The finite element model was first validated against experimental tests on a full-scale RC arch culvert, subjected to simulated live loads. The validated FE model was used in load rating analysis of 21 RC arch culverts with large fills. It was found that for arch culverts with fills exceeding 2.43 m (8 ft.), the controlling actions are bending moments at the crown and haunch. For culverts with fills greater than 3.05 m (10 ft.), live load effects become negligible. A revised rating formula is proposed for culverts with this characteristic. [ABSTRACT FROM AUTHOR]

Fibreglass reinforced flexible pipe (FGRFP) is a kind of composite thermoplastic pipe serving as a preferred application in the field of oil transportation. This paper studies the mechanical behaviour of FGRFPs under pure bending by experimental, numerical and theoretical methods. Full-scale four-point bending tests are conducted and the curvature-bending moment relations of specimens are recorded. In the numerical simulation method (NSM), a detailed finite element model considering both material and geometric nonlinear behaviour is established, and the composite is defined as an orthotropic elastic-plastic material. Based on the Euler–Bernoulli beam theory, a simplified theoretical method (STM) is proposed to predict the ultimate bending moment. In the parametric study, a simple formula is introduced to modify STM to make it more accurate. Good agreements proves the reasonability of the proposed NSM and STM. Additionally, STM could make a contribution to engineers in terms of a concise and relatively accurate way in ultimate status analysis. [ABSTRACT FROM AUTHOR]

The nonlinear dynamic behaviour of steep wave riser (SWR) subjected to the top harmonic motions considering the effect of the internal flow is numerically investigated using a three-dimensional (3D) time-domain finite element method (FEM) based on the slender flexible rod theory. In this numerical model, the riser which satisfies geometric nonlinearity is divided into three segments: decline segment, buoyancy segment and hang-off segment and the effect of the internal flow is also incorporated into motion equation using plug flow. A Newmark-β integral method is applied to update the dynamic responses at each time step. The published results for the static/dynamic performance of the steel flexible riser are used to validate the present numerical method. Numerical simulations are conducted to investigate the dependence of the tension, displacement and bending moment on the design parameters. The top motion amplitude/period, buoyancy length and internal flow density/velocity/top pressure are discussed respectively. [ABSTRACT FROM AUTHOR]

This study is concerned with evaluating the response of single pile subjected to cyclic horizontal uniaxial loading. Combination of lateral cyclic loading and constant vertical or lateral load in two-orthogonal directions is also studied. Moreover, the influence of one- and two-way loading, number of cycles and the intensity of constant load in conjunction with the cyclic lateral load is presented. The study is further continued by comparing the performance of long and short single pile embedded in clayey soil. A series of three-dimensional finite element models using ANSYS code are conducted to model three-dimensional transient analysis as well as the complicated soil pile interaction. In order to verify the validity numerical model, the numerical response is compared with reported results obtained by experimental cyclic load test performed on single pile penetrated in soft clay. Results show strong coupling between the two-orthogonal direction of lateral loading that decreases the lateral pile capacity. The interaction relation of biaxial loading with the factor b = 1.2 and 1.15 for one- and two-way loading respectively may well approximate the analysis results. The results of study are presented in terms of lateral cyclic capacities, pile head deflection, displacement profile and bending moment over the pile length. [ABSTRACT FROM AUTHOR]

From accident investigations it is found that under some unknown conditions the energy absorbing capacity and anti-overriding function of anti-climber are greatly reduced due to the serious vertical buckling. In order to analyse the vertical buckling mechanism of collided anti-climber, a simulation strategy based on the coupling finite element method and multi-body dynamics is proposed in this paper. A numerical model of anti-climber is established and validated with the quasi-static crush test. The simulation results indicate that in some train collisions the maximal overriding speed can increase as large as 1.5 m/s. Under this condition, large constraint force and bending moment are induced and applied on the collided anti-climber, resulting in a serious vertical buckling. Besides that, the initial vertical offset is identified as another important factor. Generally speaking, the buckling degree as well as the deterioration of energy absorption capacity of collided anti-climber becomes more severe with the increase of initial offset. Moreover, when the two factors (initial vertical offset and overriding speed) are coupled together, the crush behaviour of anti-climber is more complex. If the bending moments, which are induced by the initial vertical offset and overriding speed respectively, are in the same direction, the collided anti-climber is buckled seriously. On the other hand, if these bending moments are in the opposite directions, they are counteracted. As a result, the collided anti-climber is buckled less seriously and has more capacity to absorb the collision energy. [ABSTRACT FROM AUTHOR]

Sensing elements in Stress-In-Motion (SIM) system were designed to measure vertical and tangential tire-pavement contact forces under uniform loading conditions. However, in reality, the contact forces are not uniformly distributed. Compared with tangential shear force, non-uniform vertical contact force causes a bending moment which may take significant errors to tri-axial contact stress measurements. In the research, three tire thread-sensing element contact conditions (uniform, non-uniform and point load) were applied and influences of the non-uniformity on vertical and tangential stress signals were determined by finite element method. It was found that significant errors may occur as a result of the contact force non-uniformity. The error of the vertical contact force measurement was up to 65% (non-uniform load). In extreme situation with point load, the error would be greater. The errors caused by vertical contact force non-uniformity to the tangential contact stress measuring signals were 15% (non-uniform force) and 60% (point load). So designing of the SIM sensing element and decoupling method between measuring signals should be carefully reconsidered. [ABSTRACT FROM AUTHOR]

The aim of the present paper is to investigate the ultimate strength characteristics of as-built ultra-large containership hull structures under combined vertical bending and torsional moments with varying the ship size. The intelligent supersize finite element method (ISFEM) is employed for the ultimate hull girder strength analyses. A total of three as-built containerships carrying 9,300 TEU, 13,000 TEU, and 22,000 TEU are studied. Based on the computations, ultimate strength interaction relationships of containership hull girders under combined vertical bending and torsional moments are also formulated by a curve fitting. Insights and structural design recommendations obtained from the study are summarised, which will be useful to not only enhance the ultimate limit state capacity of containership hull structures in existing sizes but also achieve the robust structural design of ultra-larger containerships which have never been built before. [ABSTRACT FROM AUTHOR]

In order to study the influence of looseness on seismic performance of through-tenon joints, six through-tenon joints specimens in 1:3.2 scale, including one tight-fitted joint and five loose joints, were fabricated according to the Engineering Fabrication Methods of Qing dynasty. The failure modes, mechanical behaviors such as the hysteresis and envelope curves, strength and stiffness degradations, energy dissipation, and deformation of the specimens under low cyclic reversed loading tests were analyzed. Results show that the failure modes of theses joints under positive and negative loadings are bending damage on the big tenon head and tearing damage on the variable cross-section, respectively. The hysteresis curves of joints appear to be anti-Z shape and present typical pinching effect. The greater the degree of looseness is, the more obvious the slippage is. The bending moment, stiffness and energy dissipation of loose joints are lower than those of the tight-fitted joint under the same rotation angle, and the increase in the loose degree cause them to gradually decrease. Meanwhile, the behavior of the through-tenon joints is further simulated by the nonlinear finite element analysis program, and the test results agree well with the numerical analysis results. [ABSTRACT FROM AUTHOR]

Reticulated shell structures are commonly adopted because of their large spanning capacity and novel appearance. These structures generally comprise slender beam members, which may cause the buckling of entire structures. A shape-finding method is proposed in this study to eliminate the bending moment while optimizing the member buckling capacity of reticulated shell structures. The bending stiffness of connections can be accurately considered in the topology optimization analysis. This study can systematically be adopted for designing, analysing and optimizing such structures. All of the work presented was conducted using a general finite element analysis program and can be easily mastered by engineering designers while avoiding tedious programming work. [ABSTRACT FROM AUTHOR]

This research presents measurements and simulations of the full-scale behavior of a test embankment built on a soft marine clay deposit improved using soil–cement mixing (SCM) columns in Bangkok, Thailand, using both two-dimensional (2D) and 3D finite element analyses (FEAs). Fixed SCM columns with two different installation patterns, that is, column groups and column rows, were constructed in the soft clay foundation prior to the construction of the embankment. Three column wall methods, namely, equivalent width, equivalent axial rigidity, and equivalent flexural rigidity approaches, were used to convert the 3D individual columns into 2D plane strain column walls. A comparison of the results obtained through the 3D and 2D FEAs revealed that the 2D analyses provide inaccurate results in terms of the column lateral movements, bending moments, and axial loads induced in the SCM columns in addition to the factors of safety against slope failure. This outcome occurred because the actual columns in the 2D FEA were modeled using extended walls, which essentially prevent the movements of soil between two columns or column rows. Correction factors used to convert the 2D analysis results into 3D analysis results were also proposed in this study. [ABSTRACT FROM AUTHOR]

In the recent past, in order to cater lateral loads, provision of fins to monopiles is evolving as an option for enhancing their lateral load capacity. Numerical and experimental studies pertaining to fin piles subjected to lateral loading are very limited. It is very difficult to understand the behaviour of fin piles through conventional soil pile theories, due to their different fin configurations. In the present study, three-dimensional finite element analyses were performed on regular piles (pile without fins) as well as fin piles. For fin piles, different fin lengths, orientation and position were considered during the analyses. The results have shown that fins placed at the top portion of the piles are more effective than fins placed at bottom of the pile. In all cases, fin piles exhibited more lateral load-carrying capacity compared to regular piles. When fin's length is less than half of the pile length, lateral load-carrying capacity of fin piles is same irrespective of their orientation. However, fin's orientation is significant, when fin length is more than 0.5 times length of piles, star fin piles exhibit more lateral load-carrying capacity compared to diagonal and straight fin piles. Fin piles experienced less bending moment compared to regular piles for a given lateral load. Further, it was also noticed that lateral load-carrying capacity of the fin piles depend upon fins' length and their orientation. [ABSTRACT FROM AUTHOR]

High performance sailing yachts are generally designed assuming high local and global loads transmitted by rigs to hull structures. The above-mentioned loading conditions can become critical for large hulls also in terms of displacements when composite materials are used. In this scenario, it is very important to use lightweight and high-performance materials, such as carbon fibres. In fact, also some 'non structural' components, such as outfit and furniture, are built in carbon fibres and, therefore, can be considered contributing to the hull local and global strength. The aim of this work is to investigate the contribution level of those 'non-structural' components to the hull strength. Two different finite element models of a 94 ft sailing yacht, with and without 'non structural components', have been carried out in order to evaluate their contribution to the primary hull response to longitudinal bending moment and dock tuning load. [ABSTRACT FROM AUTHOR]

Bending behaviours of the repaired aircraft winglet were investigated in this paper. Impact damage was firstly inflicted at the center of three pristine winglets by using a drop-weight impact device. The damaged core was restored by filling in the same foam and the damaged skin was repaired by bonding to a three-dimensional scarf patch accompanied with an additional external layer (Doubler). Then, the ultimate load-bearing capacity and failure mechanism of the repaired winglets under static bending moments were studied and compared with the pristine ones. Furthermore, the influence of the stress state of the patch (tension or compression) was discussed by attaching the patch on the top and bottom respectively during testing. The experimental results show that the repaired winglets retain approximately 82% of the load capacity of pristine winglets. Damage occurs along the bolt holes on the composite skin of pristine winglets, while the repaired winglets fail due to the shear crack of the foam and debonding between the foam core and the composite skins. Finally, finite element method were used to explore the failure mechanism for repaired and pristine winglets by comparing the stress distributions. In addition, parametric studies were conducted. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to reconstruct 11 motor vehicle crashes (6 with thoracolumbar fractures and 5 without thoracolumbar fractures) and analyze the fracture mechanism, fracture predictors, and associated parameters affecting thoracolumbar spine response.Methods: Eleven frontal crashes were reconstructed with a finite element simplified vehicle model (SVM). The SVM was tuned to each case vehicle and the Total HUman Model for Safety (THUMS) Ver. 4.01 was scaled and positioned in a baseline configuration to mimic the documented precrash driver posture. The event data recorder crash pulse was applied as a boundary condition. For the 6 thoracolumbar fracture cases, 120 simulations to quantify uncertainty and response variation were performed using a Latin hypercube design of experiments (DOE) to vary seat track position, seatback angle, steering column angle, steering column position, and D-ring height. Vertebral loads and bending moments were analyzed, and lumbar spine indices (unadjusted and age-adjusted) were developed to quantify the combined loading effect. Maximum principal strain and stress data were collected in the vertebral cortical and trabecular bone. DOE data were fit to regression models to examine occupant positioning and thoracolumbar response correlations.Results: Of the 11 cases, both the vertebral compression force and bending moment progressively increased from superior to inferior vertebrae. Two thoracic spine fracture cases had higher average compression force and bending moment across all thoracic vertebral levels, compared to 9 cases without thoracic spine fractures (force: 1,200.6 vs. 640.8 N; moment: 13.7 vs. 9.2 Nm). Though there was no apparent difference in bending moment at the L1-L2 vertebrae, lumbar fracture cases exhibited higher vertebral bending moments in L3-L4 (fracture/nonfracture: 45.7 vs. 33.8 Nm). The unadjusted lumbar spine index correctly predicted thoracolumbar fracture occurrence for 9 of the 11 cases (sensitivity = 1.0; specificity = 0.6). The age-adjusted lumbar spine index correctly predicted thoracolumbar fracture occurrence for 10 of the 11 cases (sensitivity = 1.0; specificity = 0.8). The age-adjusted principal stress in the trabecular bone was an excellent indicator of fracture occurrence (sensitivity = 1.0; specificity = 1.0). A rearward seat track position and reclined seatback increased the thoracic spine bending moment by 111-329%. A more reclined seatback increased the lumbar force and bending moment by 16-165% and 67-172%, respectively.Conclusions: This study provided a computational framework for assessing thoracolumbar fractures and also quantified the effect of precrash driver posture on thoracolumbar response. Results aid in the evaluation of motor vehicle crash-induced vertebral fractures and the understanding of factors contributing to fracture risk. [ABSTRACT FROM AUTHOR]

The longitudinal strength of a ship decreases with the reduction in its bending moment capacity following a collision accident. Therefore, the damaged ship should be able to reach the closest harbour safely without any catastrophic hull girder collapse. This paper aims to develop a method to predict the hull girder residual strength of double-hull oil tankers by considering probabilistic collision damage scenarios. The collision damage index is defined as the reduction ratio of the vertical hull girder moment of inertia, and the residual strength index is (RSI) characterised as the reduction ratio of the hull girder ultimate bending moment. Four different as-built double-hull oil tankers were studied to demonstrate the proposed method and to formulate the collision damage index. The relationships between the residual strength index and the collision damage index are identified in the form of diagrams. The produced diagrams and regressions represent a first-cut assessment of a ship's safety immediately after taking collision damage. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation into the effect of lining leakage on the structural performance of lining in subsea tunnels. A parametric study on a number of hypothetical subsea tunnels was conducted within the framework of two-dimensional stress–pore pressure coupled finite element analysis with due consideration of tunnel cover depth, depth of water to seabed, and ground type. The results indicate that the lining leakage increases axial thrust as well as bending moment, with more pronounced increases in bending moment. Also shown is that there exists an increasing trend of leakage induced lining forces with an increase in the water depth above the seabed but with no significant influence from the cover depth. It is also shown that the progressive development of leakage induced lining forces can be best fitted with an exponential function which can be used to predict the lining force increase for a given tunnel condition. Practical implications of the findings are discussed. [ABSTRACT FROM PUBLISHER]

This paper presents a structural failure assessment of the engine room region of a post-Panamax containership, outside 0.4 L amidships and subject to an unexpected excessive hull girder bending moment and shearing force, with reference to the hull failure accident of the post-Panamax containership MSC Napoli. The ultimate strength of both the hull girder and stiffened panels in an as-built post-Panamax containership is estimated using ANSYS nonlinear finite element analysis and ALPS/HULL and ALPS/ULSAP programs to clarify the adequacy of the structural safety. Finally, this paper proposes an assessment procedure for preventing an unexpected catastrophe, such as that experienced by the MSC Napoli. Such accidents, although rare, result in significant economic losses and marine pollution. [ABSTRACT FROM PUBLISHER]

The elastic stress concentrations are addressed that are developed from the keyless frictionless press fit of a shaft subjected to bending into a hub with rounded bore edges. Derived from a formal modeling of the title problem in terms of an integral equation, a set of normalized parameters is proposed that accounts for the combined effects on the hub stress concentration of the fillet radius, the shaft radius, the hub outer radius, the hub axial length, the interference, the Young's modulus, and the bending couple. A numerical validation of the normalized parameters is presented. With the aid of Finite Elements, various design charts are compiled that (a) forecast the bending couple initiating the detachment between the shaft and the hub, and (b) report the elastic stress concentrations within the hub versus the proposed normalized parameters in the absence of shaft–hub detachment. Such charts assist the designer in dimensioning an interference fit in the presence of a bending couple. [ABSTRACT FROM PUBLISHER]

Introduction: The objective of this study was to reconstruct 4 real-world motor vehicle crashes (MVCs), 2 with lumbar vertebral fractures and 2 without vertebral fractures in order to elucidate the MVC and/or restraint variables that increase this injury risk.Methods: A finite element (FE) simplified vehicle model (SVM) was used in conjunction with a previously developed semi-automated tuning method to arrive at 4 SVMs that were tuned to mimic frontal crash responses of a 2006 Chevrolet Cobalt, 2012 Ford Escape, 2007 Hummer H3, and 2002 Chevrolet Cavalier. Real-world crashes in the first 2 vehicles resulted in lumbar vertebrae fractures, whereas the latter 2 did not. Once each SVM was tuned to its corresponding vehicle, the Total HUman Model for Safety (THUMS) v4.01 was positioned in 120 precrash configurations in each SVM by varying 5 parameters using a Latin hypercube design (LHD) of experiments: seat track position, seatback angle, steering column angle, steering column telescoping position, and d-ring height. For each case, the event data recorder (EDR) crash pulse was used to apply kinematic boundary conditions to the model. By analyzing cross-sectional vertebral loads, vertebral bending moments, and maximum principal strain and stress in both cortical and trabecular bone, injury metric response as a function of posture and restraint parameters was computed.Results: Tuning the SVM to specific vehicle models produced close matches between the simulated and experimental crash test responses for head, T6, and pelvis resultant acceleration; left and right femur loads; and shoulder and lap belt loads. Though vertebral load in the THUMS simulations was highly similar between injury cases and noninjury cases, the amount of bending moment was much higher for the injury cases. Seatback angle had a large effect on the maximum compressive load and bending moment in the lumbar spine, indicating the upward tilt of the seat pan in conjunction with precrash positioning may increase the likelihood of suffering lumbar injury even in frontal, planar MVCs.Conclusion: In conclusion, precrash positioning has a large effect on lumbar injury metrics. The lack of lumbar injury criteria in regulatory crash tests may have led to inadvertent design of seat pans that work to apply axial force to the spinal column during frontal crashes. [ABSTRACT FROM AUTHOR]

Objective: A cyclist assumes various cyclic postures of the lower extremities while pushing the pedals in a rotary motion while pedaling. In order to protect cyclists in collisions, it is necessary to understand what influence these postures have on the global kinematics and injuries of the cyclist.Method: Finite element (FE) analyses using models of a cyclist, bicycle, and car were conducted. In the simulations, the Total Human Model of Safety (THUMS) occupant model was employed as a cyclist, and the simulation was set up such that the cyclist was hit from its side by a car. Three representative postures of the lower extremities of the cyclist were examined, and the kinematics and injury risk of the cyclist were compared to those obtained by a pedestrian FE model. The risk of a lower extremity injury was assessed based on the knee shear displacement and the tibia bending moment.Results: When the knee position of the cyclist was higher than the hood leading edge, the hood leading edge contacted the leg of the cyclist, and the pelvis slid over the hood top and the wrap-around distance (WAD) of the cyclist's head was large. The knee was shear loaded by the hood leading edge, and the anterior cruciate ligament (ACL) ruptured. The tibia bending moment was less than the injury threshold. When the cyclist's knee position was lower than the hood leading edge, the hood leading edge contacted the thigh of the cyclist, and the cyclist rotated with the femur as the pivot point about the hood leading edge. In this case, the head impact location of the cyclist against the car was comparable to that of the pedestrian collision. The knee shear displacement and the tibia bending moment were less than the injury thresholds.Conclusion: The knee height of the cyclist relative to the hood leading edge affected the global kinematics and the head impact location against the car. The loading mode of the lower extremities was also dependent on the initial positions of the lower extremities relative to the car structures. In the foot up and front posture, the knee was loaded in a lateral shear direction by the hood leading edge and as a result the ACL ruptured. The bicycle frame and the struck-side lower extremity interacted and could influence the loadings on lower extremities. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to propose a practical computational procedure for the long-term distribution of combined wave and whipping bending moments (BMs) of container ships. The problem is formulated in the frequency domain using standard engineering tools for load computation: a seakeeping code for the rigid-body response and a beam finite element model for transient vibratory response. The von Karman approach with correction for pile-up effect is employed for bow flare slamming load assessment. Correlation between wave and whipping BMs is considered. The procedure is demonstrated on the example of a 9200 TEU container ship. Long-term distributions of combined BMs are computed using the standard International Association of Classification Societies scatter diagram for the North Atlantic environment and two additional scatter diagrams for common shipping routes of container ships. The speed profile required for the long-term load prediction is calculated by the seakeeping analysis respecting operability limiting criteria. Conclusions about influence of various environmental and operability parameters are drawn. [ABSTRACT FROM PUBLISHER]

Bi-adhesive joints are an alternative stress-reduction technique for adhesively bonded joints. The joints have two types of adhesives in the overlap region. The stiff adhesive should be located in the middle and the flexible adhesive at the ends. This study is the extension of our previous paper to the von Mises stress evaluation and discusses the values and importance of the von Mises stresses in the bi-adhesive single-lap joint. Both analytical and numerical analyses were performed using three different bi-adhesive bondline configurations. The Zhao’s closed form (analytic) solution used includes the bending moment effect. In the finite element models, overlap surfaces of the adherends and the adhesives were modeled using surface-to-surface contact elements. The contribution levels of the peel and shear stresses for producing a peak von Mises stress are also studied. It is concluded that the contribution level of the shear stress at where von Mises stress becomes peak is more than that of the peel stress. Joint strength analyses were performed based on the peak elastic von Mises stresses. It is seen that joint strength can be increased using bi-adhesive bondline. The analytical and numerical results show that the appropriate bond-length ratio must be used to obtain high joint strength. [ABSTRACT FROM AUTHOR]

The risk of a fatigue failure has to be evaluated at coupling joints of older post-tensioned, concrete bridges in Germany, because weaknesses were identified in the design of these bridges. Because of the nonlinear bearing behaviour of post-tensioned, concrete structures, the results of this analysis strongly depend on the distribution of the permanent internal forces, which are uncertain due to time-dependent losses and redistributions. In this paper, a method to determine the bearing behaviour and the actual bending moment of the examined coupling joint, which is based on non-destructive, long-term measurements under service conditions, is shown. Therefore, the crack at the coupling joint, the temperatures and the traffic loading are observed. The results are used to calibrate a finite element simulation of the cross section. With this, a more realistic fatigue evaluation could be done as of the approaches in codes for the design of new bridges are used (e.g. DIN EN 1992, 2011,Eurocode 2. Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken, Berlin: Beuth). [ABSTRACT FROM AUTHOR]

This paper proposes a general procedure to develop arbitrary noded-plate macroelements with C1-continuity based on Coons’ interpolation formula. The novelty of the proposed approach lies in the fact that the degrees of freedom appear only along the boundaries of the quadrilateral patch and are used for the successful calculation of displacements and relevant stresses. The boundary nodes are being interpolated using univariate Hermitian polynomials, thus allowing bivariate global shape functions to be automatically produced. The proposed macroelement, which will be hereafter called COPE (Coons’ Plate Element), provides comparable results with closed-form analytical solutions in six benchmark plate-bending cases. [ABSTRACT FROM PUBLISHER]

The objective of this paper is to develop a modified Paik–Mansour formula for the ultimate strength calculations of ship hulls subject to vertical bending moments. The method is based on a credible bending stress distribution over the hull cross-section presumed at the ultimate limit state. The accuracy of this method is demonstrated through comparison with computations obtained using more refined methods, such as non-linear finite-element method, intelligent super-size finite-element method, and idealised structural unit method. Statistical analysis of the hull girder ultimate strength based on comparisons among the various computations is carried out in terms of their mean values and coefficients of variation. The original Paik–Mansour method is found to be inapplicable to the case of a pure vertical bending moment depending on the ship's hull type and/or vertical bending direction, but the modified Paik–Mansour method is more general and is able to resolve this issue. [ABSTRACT FROM PUBLISHER]

In this study, simulations of car-to-pedestrian collisions were conducted using multibody pedestrian models and a finite-element (FE) car model in order to examine the loadings on the lower extremity of the pedestrian. Bending moment diagrams were plotted versus time for the tibia, knee and femur; and the loadings on the lower extremities were evaluated using time-series comparisons. An analysis using a human FE pedestrian model also was conducted. The bending moment of the lower extremity was found to be comparable between the multibody and FE models. Car-to-pedestrian collisions were also simulated for various sizes of pedestrians. The bending moments were larger as the pedestrian size was larger, whereas the curve shape of the bending moment diagrams was similar for all sizes of pedestrians. It was shown that the bending moment diagrams using the multibody pedestrian models were useful for investigating the loading on the lower extremities for various sizes of pedestrians. [ABSTRACT FROM AUTHOR]

A mixed finite element model for the nonlinear bending analysis of laminated composite plates is presented. The finite element model is obtained using a mixed variational formulation of the first-order shear deformation theory of plates in which displacements and bending moments are treated as independent fields. A p-type Lagrangian basis is used to approximate the nodal degrees of freedom that consist of three displacements, two rotations, and three moment resultants. The geometric nonlinearity in the sense of the von Kàrman is included in the plate theory. The mixed plate element developed herein is employed in the linear and nonlinear bending analysis of a variety of layered composite rectangular plates. The effects of transverse shear deformation, material anisotropy, and bending-stretching coupling on deflections and stresses are investigated. The predictive capability of the present model is demonstrated by comparison with analytical, experimental, and numerical solutions available in the literature. The model provides an accurate prediction of the global bending response of thin and moderately thick plates subjected to moderate and moderately large rotations. The inclusion of the bending moments at the nodes results in increased accuracy in the computation of stresses over those determined by conventional displacement-based finite element models. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical behavior of the Single-Lap Joints (SLJs) bonded with two different adhesives (FM 73 and SBT 9244) under a bending moment was analyzed, both experimentally and numerically. Four-point bending experiments for the joints with different overlap lengths were carried out and fracture surfaces of the SLJs were examined with a Scanning Electron Microscope (SEM). After the stress analysis in the SLJs was performed via a finite element method by considering the material non-linearities of the adhesives and adherend (AA2024-T3), the Finite Element Analysis (FEA) results were compared with experimental results. Finally, the stress analyses and experimental results show that the failure in the SLJs subjected to a bending moment probably initiates from the overlap region on the adhesive–upper adherend interface in tension and propagates towards the centre of the overlap. Also, in the joint subjected to a bending moment, it is seen that the load carried by the SLJ with SBT 9244 adhesive with increasing overlap length is more than that of the SLJ with FM 73 adhesive, although in the bulk form FM 73 adhesive is about three times stronger than SBT 9244 adhesive. [ABSTRACT FROM AUTHOR]

In this work, elasto-plastic stress analysis of a Single Lap Joint (SLJ) subjected to bending moment was investigated using 2D non-linear Finite Element Analysis (FEA). The SLJs, consisting of hardened steel as the adherend bonded by two adhesives, one stiff and one flexible, with very different mechanical behaviors were analyzed. In order to determine the effect of geometrical parameters on the performance of the SLJs, four different adherend thicknesses and overlap lengths for each adhesive were used. For verification of the analysis, the FEA results were compared with experimental results. It was observed that there was a significant effect of adherend thickness on the strength of the joint with both adhesives. However, the load carried by the SLJ with the flexible adhesive increased with increasing overlap length. [ABSTRACT FROM AUTHOR]