Progressive Failure Model Research Articles

Failure analysis of composite pre-tightened teeth joints under bending and tension coupling load

With the application of composite pre-tightened tooth joint in engineering practice, relevant studies have found that in actual structures, the joints are subjected not only to axial tension but also to bending and tension coupling force. Therefore, to analyse the load mechanism and progressive failure process of the joint under bending-tension coupling, a experiment loading method for joint structure was first designed in this paper, and axial-tension and bending-tension coupling experiments of single and double teeth were carried out by this method. Then, a three-dimensional model of progressive failure based on the USDFLD subroutine and Tsai-Wu failure criterion is established based on the experiment condition, and finally, the progressive failure process of the joint in the case of bending-tension coupling is analysed by verifying the correctness of the finite element simulation. The study revealed that the top surface of the composite tooth is subjected to the combined effects of tension stress from the bending moment and tension stress from the axial force at the same time, so the joint damage starts at the top surface and the stress state at the top surface of the composite tooth needs to be considered.

Mesoscale modelling of progressive damage and failure in single-lap and double-lap thin-ply laminated composite bolted joints

Composite bolted joints are being used extensively in primary load-bearing structures of modern aircrafts. However, simulating progressive damage and failure of the bolted composite structures under high bearing loading is still challenging. In this paper, numerical simulation and experimental verification on the bearing failure of single-lap and double-lap thin-ply laminated composite bolted joints were carried out for the entire loading process. 3D explicit finite element models have been developed using Abaqus/Explicit together with a 3D physically-based intralaminar damage model implemented in a VUMAT subroutine. An interface cohesive-zone model based on the Benzeggagh-Kenane (B-K) law was used to simulate delamination initiation and evolution. For the intralaminar damage, the initiation was determined based on Pinho’s failure criteria while the evolution was regularized with the crack-band approach to alleviate mesh-size dependence. Element deletion and in-situ effect as practical numerical strategy are discussed and analyzed in detail. Element deletion is used to prevent excessive element distortion and capture corresponding post-peak bearing failure behavior. In-situ effect has been proved to have a key influence on the damage initiation and progression of thin-ply composite matrix. The final simulation results are shown to agree well with experimental data and reproduce the mechanical response curves. More importantly, the model can accurately capture the local crushing of bolt hole in the later loading stage. This study shows that the numerical model can be helpful for the design and optimization of composite bolted structures.

Axial crushing of circular thin-walled specimens made of CFRP using progressive failure model (MAT54) in LS-Dyna

This research focuses on calibrating the MAT54 (ENHANCED_COMPOSITE_DAMAGE) material card in LS-Dyna for simulating axial crushing of circular thin-walled specimens made of CFRP. An IM7/8552 composite specimen showing the layup sequence of [902/±452/02]2 was simulated in LS-Dyna using shell elements. Following a trial-and-error-based method, the physical and non-physical input material parameters of MAT54 were calibrated. The calibrated input parameters included material strengths, failure strains, softening factors, and damping coefficient. The results of this study showed the applicability of the use of the physical material inputs from material characterization tests (e.g., tensile, in-plane shear, and compression) while showing the necessity of more in-depth calibration processes for the non-physical material inputs (e.g., viscous damping coefficient, crashfront reduction algorithm, etc.). The initial model predicted the specific energy absorption with an error of −57.95 % and this was improved by the calibration process to an error equal to −1.49 % for the final model. Now validated, the model will be used in the future to simulate impact into composite vehicle armor.

A review on micromechanical modelling of progressive failure in unidirectional fibre-reinforced composites

The recent decades have seen various attempts at the numerical modelling of fibre-reinforced polymer (FRP) composites in the aerospace, auto and marine sectors due to their excellent mechanical properties. However, it is still challenging to accurately predict the failure of the composites because of their anisotropic and inhomogeneous characteristics, multiple failure modes and their interaction, especially under multiaxial loading conditions. Micromechanics-based numerical models, such as representative volume elements (RVEs), were developed to understand the progressive failure mechanisms of composites, and assessing existing failure criteria. To this aim, this review paper summarises the development of micromechanics-based RVE modelling of unidirectional (UD) FRP composites reported in the literature, with a focus on those models developed using finite element (FE) and discrete element (DE) methods. The generation of fibre spatial distribution, constitutive models of material constituents as well as periodic boundary conditions are briefly introduced. The progressive failure mechanisms of UD FRP composites simulated by RVEs under various loadings are discussed and the comparison of failure envelopes predicted by numerical results and classical failure criteria are reviewed.

Numerical modelling of progressive failure in fiber-reinforced polymer composites under quasi-static loading

The demand for fibre-reinforced polymer (FRP) composites has been increasing in the last decades due to their excellent mechanical properties when compared to traditional materials. However, this class of materials has a more complex stress-strain response, which requires improved design methodologies. To take advantage of these unique characteristics and efficiently design structures, the usage of finite element analysis to predict progressive failure can be a powerful tool. Hence, in the present study, a method for predicting the initialization and progression of matrix and fibre damage in fibre-reinforced polymer composites was implemented using Puck's failure criterion and the Element Weakening Method (EWM). This numerical approach was validated using Digital Image Correlation (DIC) measurements and monotonic tensile tests to evaluate the ultimate load. The results show that the implemented method is able to predict the strain field at the specimen surface as well as the ultimate load level.

Application of Random Radial Point Interpolation Method to Foundations Bearing Capacity Considering Progressive Failure

In conventional analyzes of foundations failure, strengh parameters are assumed constant. However, during the failure, soil resistance exhibits maximum and residual amounts, and its strength decreases prematurely by increasing the plastic strain. In addition to change soil strengh parameters in the progressive mechanism, the non-uniform nature of the soil also causes spatial variations of these parameters. Therefore, geotechnical systems should be considered in terms of the uncertainty of soil parameters values, uncertainly using the concepts of statistics and probabilities. The purpose of this study is to investigate foundations in meshless method. In this article, radial point interpolation method (RPIM), a meshless method is proposed for simulation of soil foundation. Difficulties of methods related to mesh are solved by using this method. A code has been developed based on this method and some examples are solved for analyzing the code. In this research, a RPIM in combination with a random field was used to model the spatial variations of soil strengh properties and foundation bearing capacity analysis. For probabilistic analysis, random field is also used to determine the cohesion and the friction angle as well as the dilation angle based on their mean values and standard deviation. In order to investigate the application of the point interpolation method with randomized radial functions, a foundation with definite geometry has been analyzed deterministic and probabilistic and its safety factor has been investigated. Based on the analysis of the progressive failure modeling, it is concluded that the actual failure of the soil and the occurrence of continuous displacements occur simultaneously with the formation of a progressive mechanism of soil failure and the arrival of the slipping path to the ground. In the following, probabilistic distribution functions of the safety factor were determined by probabilistic analysis and the production of random fields, and then the statistical parameters are calculated.

Face stability analysis of cohesion-frictional soils considering the soil arch effect and the instability failure process

Based on the limit equilibrium method, a new three-dimensional progressive failure model, which includes the upper loose zone and the lower slip zone, is proposed to analyze the stability of a tunnel face. In the model, the ellipsoid of the upper loose zone is discretized into a plurality of frustums. Considering the soil arch effect, the theoretical solution of loose earth pressure under an arbitrary slip surface dip angle is calculated iteratively based on the principal stress rotation theory. The limit support pressure of the three-dimensional failure model is obtained. Then, the accuracy and effectiveness of the new model are verified by comparison with existing model tests and theoretical methods. Finally, the effect of the soil parameters on the limit support pressure is discussed. The relation curve between the loose zone height and the support pressure is determined. The instability failure process of the tunnel face is analyzed. The results show that the internal friction angle and cohesion have significant effects on the limit support pressure. The tunnel face instability failure process is defined. As the height of the loose zone increases, the limit support pressure decreases sharply first, then increases slowly, and finally reaches a fixed value.

Three-dimensional phase field modeling of progressive failure in aramid short fiber reinforced paper

As a kind of synthetic aromatic polyamide, aramid fiber has many outstanding properties, such as high strength, high modulus, etc. The composited paper reinforced by aramid fiber is widely used in honeycombs and its strength is of great concerns. In this paper, a three-dimensional progressive failure phase field model is employed to investigate the failure mechanism of aramid honeycomb paper under microscopic length scale. A mesh mapping technique is used to handle the complex geometry of the material, and an explicit solving scheme is used to improve the solving efficiency. The theory is implemented into ABAQUS through the users’ subroutine VUEL. The interfacial debounding and matrix cracking in the short fiber reinforced composite are captured successfully, and the complicated failure mechanism is explored from the modeling results. The present phase field modeling technique has provided a useful numerical tool for the strength prediction of aramid short fiber reinforced composites.

Three-dimensional numerical modelling of progressive failure of caisson foundation in sand using a coupled FDM–DEM method

Bearing capacity and the relationship between loading and displacement for caisson foundations have been widely studied, but failure mechanism and loading response at the micro level were out of their reach. Considering the pros and cons of both discrete and continuum methods, this study investigates the progressive failure of caisson foundation in sand using the coupled FDM–DEM (Finite Difference Method – Discrete Element Method) method. The caisson is modelled by shell elements of FDM and its surrounding soils in a limited area are modelled by spherical particles of DEM with the rest part of soil modelled by FDM. Rolling resistance contact model is used to account for the effect of particle shape of sand. A series of scale model tests are simulated for investigating the failure process of the caisson foundation in sand under various combined horizontal force and moment loadings. Based on simulations, the macro and micro characteristics of surrounding soils of caisson are analysed during the failure process of the foundation. In particular, soil displacement, rotation, force chain and fabric anisotropy in failure zone are analysed at particle level to explain macro responses, which improves the understanding of the micro-mechanisms in the progressive failure process of caisson foundation.

Multi-Scale Nonlinear Progressive Damage and Failure Analysis for Open-Hole Composite Laminates

In order to study the nonlinear behaviors and interactions among the constituents for the composite material structure under the tensile load, multiscale damage model using generalized method of cells (GMC) and a lamina-level progressive damage model were established, respectively, for fiber reinforced composite laminates with a central hole, which were based on the thermodynamic Schapery Theory (ST) at either the micro-level or the lamina level. Once the nonlinear progressive degradation of the matrix material reached the lower limit value for the ST method, matrix failures naturally occurred, the failure of the fiber was determined by the maximum stress failure criterion. For the multiscale progressive damage model, the GMC model consisting of a fiber subcell and three matrix subcells was imposed at each integral point of FEM elements, and the three matrix subcells undergo independent damage evolution. The load versus displacement curves and failure modes of the open-hole laminates were predicted by using the two progressive failure models, and the results were compared with that obtained by the Hashin-Rotem progressive failure model and the experimental results. The results show that the ST based method can obtain the nonlinear progressive damage evolution states and failure states of the composite at both the lamina level and the multiscale level. Finally, the damage contours and failure paths obtained are also presented.

Effect of Defects Part I: Degradation of Constitutive Coefficients as an Input to the Composite Failure Model with Microvoids and Porosity

It is always challenging to provide appropriate material properties for a composite progressive failure model. The nonstandard percentage reduction method that is commonly used to degrade the material constants with micro-scale defects generates tremendous uncertainty in failure prediction. The constitutive matrix is composed of multiple material constants. It is not necessary that all constants degrade either equally or linearly due to a certain state of material defects. With this very concern in mind, this article presents a guideline for using a quantified perturbation for each coefficient appropriately. It also presents distribution of effective material properties (EMPs) in unidirectional composite materials with different states of defects such as voids. Irrespective of resin transfer molding (RTM) or chemical vapor infiltration (CVI) processes, manufacturers’ defects such as voids of different shapes and sizes are the most common that occur in composite materials. Hence, it is important to quantify the ‘effects of defects’ void content herein on each material coefficient and EMP. In this article, stochastically distributed void parameters such as the void content by percent, size, shape, and location are considered. Void diameters and shapes were extracted from scanning acoustic microscope (SAM) images of 300,000 cycles of a fatigued composite. The EMPs were calculated by considering unit cells, homogenization techniques, and micromechanical concepts. The periodic boundary conditions were applied to unit cells to calculate the EMPs. The result showed that EMPs were degraded even when there was a small percentage of the void content. More importantly, the constitutive coefficients did not degrade equally but had a definitive pattern.

Design optimization of bioinspired helicoidal CFRPP/GFRPP hybrid composites for multiple low-velocity impact loads

Low-velocity impact (LVI) on continuous fiber reinforced thermoplastics (CoFRTPs) has been extensively studied with a focus on single material. Impact characteristics and optimal design of hybrid CoFRTPs have not been well addressed even though they are of considerable advantages in balancing cost and performance. This study aims to develop design optimization of bio-inspired hybrid CoFRTPs to resist multiple impact loads. In this study, the LVI behaviors of carbon fiber reinforced polypropylene (CFRPP) and glass fiber reinforced polypropylene (GFRPP) composites were first characterized experimentally, respectively. Three typical failure modes were identified in both the CFRPP and GFRPP specimens, and GFRPP exhibited better impact toughness than CFRPP. Second, a progressive failure model (PFM) was developed for finite element analysis, and numerical results in LVI damage modes and force-displacement curves agreed quite well with the corresponding experimental data. Third, parametric studies indicated that peak energy absorptions of CFRPP and GFRPP specimens respectively decreased by 20.9% and 25.5% with impact angles varying from 0° to 30°, and design of helicoidal stacking configuration can effectively enhance the LVI resistances for both the CFRPP and GFRPP specimens. Hybridization of CFRPP and GFRPP enables to improve LVI resistances and reduce the material costs. Finally, a multiobjective optimization was performed to optimize material cost and LVI resistance of helicoidal CFRPP/GFRPP hybrid composites accounting for multiple impact loads, which increased the peak energy absorption by 31.0% and reduced material cost by 33.4% compared with the baseline design. This study is anticipated to introduce an optimum configuration of hybrid composites for bearing multiple low-velocity impact loads.

Collapse analysis of the multi-span reinforced concrete arch bridge of Caprigliola, Italy

On April 2020, the 260 m-long reinforced concrete (RC) arch bridge of Caprigliola (Massa and Carrara, Italy) suddenly collapsed into the Magra river. In this work, aimed at investigating potential reasons behind the observed failure, a numerical study is conducted using the Applied Element Method (AEM), which allows the explicitly modelling of damage propagation and progressive failure up until complete collapse. Both local and global models of varying levels of detail have been developed and the consequences of different possible failure scenarios induced by selected potential triggering factors are compared with publicly available forensic evidence. Although only cross-correlations against future official post-collapse reports, currently not available, might permit the establishment of more definitive conclusions on the causes behind the observed collapse of the bridge, a seemingly good agreement was nonetheless found between predicted and observed damage and debris distribution for one of the modelled scenarios (induced movements of one of the bridge piers/abutments), which may thus be deemed as potentially more plausible than the others.

Abstract 9084: Selective Beta3-Adrenergic Receptor Antagonist Therapy Causes Regression of Cardiac Dysfunction in a Rat Model of Progressive Heart Failure: Insights into Molecular and Cellular Mechanisms

Background: Heart failure (CHF) causes cardiac β 3 -adrenergic receptor (AR) upregulation with resultant enhanced β 3 -AR-stimulated-G i -coupled negative modulation on cardiac function. This suggests a direct and contributing role of β 3 -AR activation on CHF progression. However, its precise role is unclear. We hypothesize that up-regulation of cardiac β 3 -AR promotes CHF progression. Chronic β 3 -AR antagonist (ANT) may improve Left ventricular (LV) myocyte function, and β-adrenergic reserve, thus preventing the progression of CHF. Methods: LV and myocyte functional response and β 1 - and β 3 -AR expression were compared in 3 groups of SD male rats (8 each) during 3 months: 1) CHF, 3 months after receiving Isoproterenol (ISO, 170 mg/kg, sq, for 2 days); 2) CHF/β 3 -ANT, 2 months after receiving ISO, L-748,337, a selective β 3 -AR antagonist (β 3 -ANT) (10 -7 M/kg/day, mini pump) was initiated and was given for 1 month; and 3) sham controls. Results: Versus controls, ISO-treated rats had CHF onset at 1 month after ISO and progressed to severe CHF at 3 months. Plasma norepinephrine (NE, 1298 vs 261 pg/ml) increased 4-fold; whereas, stroke volume (SV) and ejection fraction (EF, 34 vs 62%) decreased more than 45%. These changes were parallel with significant reductions in cell contraction (dL/dt max , 95 vs 189 μm/s), relaxation (dR/dt max ,75 vs 158 μm/s) and [Ca 2+ ] i transient ([Ca 2+ ] iT ) (0.17 vs 0.26). Acute superfusion of ISO (10 -8 M) caused much less increases in dL/dt max (34 vs 74%), dR/dt max and [Ca 2+ ] IT (14 vs 28%). These changes were associated with significantly decreased β 1 -AR mRNA (52%, 0.30 vs 0.62), but increased β 3 -AR mRNA (119%, 1.25 vs 0.57) expression. CHF with β 3 -ANT treatment, significantly decreased plasma NE (197 pg/ml). EF (59%) and SV returned to normal control values. The signal ratios of β 1 -AR mRNA (0.59) and β 3 -AR mRNA (0.66) recovered to control levels. ISO-induced increases in dL/dt max (75%), dR/dt max and [Ca 2+ ] iT were also significantly augmented. Conclusion: Chronic β 3 -ANT leads to normalization of LV myocyte β 1 - and β 3 -AR gene expression, restores normal LV myocyte β-AR reserve, and leads to regression of LV and myocyte dysfunction in a rat model of progressive CHF. Thus, β 3 -AR blocker may provide a new therapeutic strategy for the treatment of CHF.

Progressive failure model of high strength glass fiber composite structure in hygrothermal environment

In this paper, a progressive damage model considering hygrothermal effect is established. Taking high strength glass fiber composite plate as an example, the progressive damage model of open-hole composite plate is established, and the ultimate tensile and compressive strength at room temperature, dry state and hygrothermal environment are predicted. The model was verified by comparing with the experimental results. The results of numerical simulation and experiment show that the hygrothermal environment has a significant effect on the ultimate strength of open-hole composite plate. The tensile ultimate strength of open-hole composite plate decreases about 39% and the compressive ultimate strength decreases about 35% at 70 °C and equilibrium moisture absorption. The results show that hygrothermal environment has little effect on the tensile stiffness of open-hole composite plate, and the tensile modulus decreases by 6% at 70 °C and equilibrium moisture absorption. According to the numerical results, the hygrothermal environment can shorten the damage propagation process of the open-hole composite plate under tensile load, but does not affect the damage propagation process under compression load. The hygrothermal environment can change the macro failure diagram of the open-hole composite plate under tension from “X” to “I”, but does not affect the macro failure diagram of the open-hole composite plate under compression.

Finite element modeling of crushing of CFRP cylindrical tubes under low-velocity axial impact

The dynamic axial crushing response of cylindrical tubes made of unidirectional (UD) carbon fiber-epoxy material is investigated numerically with emphasis on generating realistic crushing modes and crushing morphologies besides predicting crushing force with good accuracy. The emphasis is on the crushing modes since only the strong similarity between predicted crushed modes by the FE model and experimental observations can assure that the FE model dissipates the energy in the same manner that real composite absorbers dissipate it during the experimental trial. The impact behavior of two multi-layer models of laminated cylindrical tubes having different stacking sequences, namely cross-ply and angle-ply, were simulated using stacked layers of conventional 2D shell elements (S4R) bonded with the cohesive element interface model in ABAQUS. The FE progressive failure model of UD composite layers, including the damage initiations, damage evolution law, and element removal, is executed through a user-defined material subroutine (VUMAT) in ABAQUS/Explicit code. The implemented progressive failure material model represented well the various crushing modes, including fragmentation mode, splaying mode, and axial splitting of UD lamina in the splaying crushing mode. The FE model was validated by experimental test results obtained by the authors for cross-ply and angle-ply tubes subjected to axial impact.

Stochastic analysis of failure pressure in reinforced thermoplastic pipes under axial loading and external pressure

Reinforced thermoplastic pipes (RTPs) are flexible composite pipes that are acknowledged as a good alternative to conventional submarine pipes. This study aims at investigating the impact of the uncertainties involved in the production process of the RTPs on the failure pressure under combined loading conditions. The stress distributions of RTPs were analyzed using the theory of the three-dimensional (3D) thick-walled cylinder method, combined with the homogenization method. Based on these results, to evaluate the failure mechanisms of RTPs, the 3D Hashin–Yeh failure criterion and the damage evolution model were adopted to establish a progressive failure model. For analyzing the influence of randomness of the related parameters on the first-ply failure (FPF) pressure as well as the final burst failure (FF) pressure of RTPs, a sufficient number of samples were generated using the Monte-Carlo method. Results of the stochastic analysis were validated using the hydraulic burst test data. The statistical evaluation of the stochastic analysis results was performed by using the Weibull probability density distribution function, and the results showed an increase in the probability of getting a lower failure pressure of RTPs than the average failure pressure (considering the randomness of production parameters).

Scale-span modelling of dynamic progressive failure in drilling CFRPs using a tapered drill-reamer

The focus of this study is exploring a scale-span modeling method to simulate the structural mechanical responses and dynamic progressive failure behaviors of carbon fiber reinforced plastics (CFRPs) in drilling. A dynamic progressive failure theory based on modified micromechanics of failure (MMF) criterion with new damage evolution laws was first introduced for intralaminar damage. The relationship between macroscopic stress and microscopic stress was established by the stress amplification factors (SAFs). Meanwhile, an auxiliary deleting element criterion was introduced to delete the serious distortion elements for the sake of preventing nonconvergence of the simulation model, and the bilinear cohesive model with mixed-mode failure criterion was employed to simulate the interlaminar delamination. Then, the drilling behaviors of T700S-12 K/YP-H26 CFRPs using a tapered drill-reamer (TDR) were simulated based on the established scale-span theory model which is implemented by user-defined material subroutine VUMAT built on ABAQUS/Explicit platform. Finally, a series of experiments were performed to validate correctness of the simulation results from the perspectives of hole-making quality evaluation index. Results show that the established scale-span simulation model is shown to agree reasonably well with the experiments, and different kinds of damage behavior of the prefabricated hole can be truly simulated in drilling CFRPs.

Chronic GPR30 agonist therapy causes restoration of normal cardiac functional performance in a male mouse model of progressive heart failure: Insights into cellular mechanisms

AimsG protein-coupled estrogen receptor 30 (GPR30) activation by its agonist, G1, exhibits beneficial actions in female with heart failure (HF). Recent evidence indicates its cardiovascular benefits may also include male as well. However, whether and how GPR30 activation may limit HF progression and have a salutary role in males is unknown. We hypothesized that chronic G1 treatment improves LV and cardiomyocyte function, [Ca2+]i regulation and β-adrenergic reserve, thus limiting HF progression in male. Main methodsWe compared left ventricle (LV) and myocyte function, [Ca2+]i transient ([Ca2+]iT) and β-AR modulation in control male mice (12/group) and isoproterenol-induced HF (150 mg/kg s.c. for 2 days). Two weeks after isoproterenol injection, HF mice received placebo, or G1 (150 μg/kg/day s.c. mini-pump) for 2 weeks. Key findingsIsoproterenol-treated mice exhibited HF with preserved ejection fraction (HFpEF) at 2-weeks and progressed to HF with reduced EF (HFrEF) at 4-weeks, manifested by significantly increased LV time constant of relaxation (τ), decreased EF and mitral flow (dV/dtmax), which were accompanied by reduced myocyte contraction (dL/dtmax), relaxation (dR/dtmax) and [Ca2+]iT. Acute isoproterenol-superfusion caused significantly smaller increases in dL/dtmax, dR/dtmax and [Ca2+]iT. G1 treatment in HF increased basal and isoproterenol-stimulated increases in EF and LV contractility of EES. Importantly, G1 improved basal and isoproterenol-stimulated dL/dtmax, dR/dtmax and [Ca2+]iT to control levels and restored normal cardiac β-AR subtypes modulation. SignificanceChronic G1 treatment restores normal myocyte basal and β-AR-stimulated contraction, relaxation, and [Ca2+]iT, thereby reversing LV dysfunction and playing a rescue role in a male mouse model of HF.

Physical modeling of progressive damage and failure of wood-frame coastal residential structures due to surge and wave forces

A physical model study was performed to examine the forces and response of 1:6 scale wood-frame coastal residential structures subjected to storm surge and waves. An on-grade and an elevated specimen were tested and exposed to regular waves with varying water depths and wave heights to simulate typical wave/surge conditions resulting from landfall hurricanes on low-lying barrier islands such as Hurricane Sandy that impacted the US East Coast in 2012 and Hurricane Ike that affected the US Gulf Coast in 2008. Results show that through careful design, wood-frame model specimens can be constructed to have similar strength and stiffness compared to full-scale structures. The two specimens were subjected to increasing surge and wave conditions, and the progressive damage was monitored using LiDAR. The on-grade specimen failed at a lower water level than the elevated specimen as expected. Both specimens showed failure modes consistent with the observed damage of residential structures in Ortley Beach, NJ, after Hurricane Sandy and on the Bolivar Peninsula, TX, after Hurricane Ike. The pressure distribution on the underside of the elevated structure and the resulting vertical forces on the on-grade structure were also examined in this study. The pressure distribution and the resulting vertical forces were significantly affected by water depth, wave height, and air gap. The results indicate that maximum vertical forces are positively correlated to wave height and water depth and negatively correlated to the air gap. The breaking type also affects vertical forces. Nonbreaking waves correlated to relatively small vertical forces, and waves breaking directly on the specimen correlated to peak vertical forces. Accelerometer data showed that the specimen decreased in stiffness during the tests due to progressive damage. An uplift pressure distribution equation was developed for an elevated residential structure as a function of wave height and air gap. The equation is generally conservative when compared to other data sets. The results and data presented in this study increase the current knowledge of the interaction between waves and residential structures, which may be useful to increase the resiliency of coastal communities.