Finite Element Stress Response Analysis of Stepped-Lap Adhesive Joints Subjected to Impact Tensile Load

2000 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Takahiro Ohmori
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Principal Stress ◽  
Impact Load ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Maximum Value ◽  
Adhesive Thickness ◽  
The Impact

Abstract The stress wave propagation and the stress distribution in stepped-lap adhesive joints of similar adherends subjected to impact tensile loads and elastic deformation are analyzed using three-dimensional finite-element method (FEM). The impact load is applied to the joint by dropping a weight. One end of the upper adherend is fixed, and the other end of the lower adherend is subjected to an impact load. FEM code employed is DYNA3D. The effects of Young’s modulus of the adherends, the number of lapped steps, and the adhesive thickness on the stress wave propagation at the lapped, and fee butted interfaces are examined. It is also found that the maximum value of the maximum principal stress σ1 occurs at the end of the butted interface between the adhesive and the lower adherend to which the impact load is applied. As the number of the lapped steps increases, the maximum value of the maximum principal stress σ1 increases. It is found that the maximum value of the maximum principal stress σ1 increases as the adhesive thickness decreases. The maximum value of σ1 increases as Young’s modulus of the adherends increases. In addition, the experiments were carried out to measure the strain response of stepped-lap adhesive joints subjected to impact tensile loads using strain gauges. A fairly good agreement is seen between the analytical, and the experimental results.

Finite Element Stress Response Analysis of Butt Adhesive Joints of Hollow Cylinders Subjected to Impact Bending Moments

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yoshihito Suzuki ◽  
Shoichi Kido
Keyword(s):  
Finite Element ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Strain Response ◽  
Bending Moments ◽  
Maximum Value ◽  
Adhesive Thickness ◽  
Hollow Cylinders ◽  
Impact Bending ◽  
The Impact

The stress variation in butt adhesive joints of hollow cylinders subjected to impact bending moments was analyzed in elasto-plastic deformation ranges using finite element method. The impact bending moments were applied to the loading side adherend of the joint by dropping a weight. The name of FEM code employed was DYNA3D. The effects of Young’s modulus of the adhesive and the effect of the adhesive thickness on the stress variations at the interfaces were examined. In addition, the characteristics of joints subjected to the impact bending moments were compared with those of the joints under static bending moments, and the strength of the joints under impact bending moments was estimated by using the interface stress distributions. As the results, it was found that (1) the maximum value of the maximum principal stress σ1 occurred at the outside edges of the fixed side adhesive interface under the impact bending moments; (2) The maximum value of maximum principal stress σ1 increased as Young’s modulus of the adhesive increased when the joints were subjected to impact bending moments; (3) The maximum value of σ1 increased as the adhesive thickness decreased; (4) the characteristics of joints subjected to the impact bending moments were opposed to those subjected to the static bending moments. In addition, experiments were carried out to measure the strain response of butt adhesive joints subjected to impact bending moments using strain gauges, and the joint strengths were also measured. The measured strain response was compared with the numerical results. A fairly good agreement was found between the numerical and the measured results concerning the strain responses.

FEM Stress Analysis and Strength of Scarf Adhesive Joints of Similar Adherend Subjected to Impact Tensile Loadings

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yuya Hirayama ◽  
He Dan
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Stress Wave ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Adhesive Thickness ◽  
Three Dimensional Finite Element

The stress wave propagation and stress distribution in scarf adhesive joints have been analyzed using three-dimensional finite element method (FEM). The FEM code employed was LS-DYNA. An impact tensile loading was applied to the joint by dropping a weight. The effect of the scarf angle, Young’s modulus of the adhesive and adhesive thickness on the stress wave propagations and stress distributions at the interfaces have been examined. As the results, it was found that the point where the maximum principal stress becomes maximum changes between 52 degree and 60 degree under impact tensile loadings. The maximum value of the maximum principal stress increases as scarf angle decreases, Young’s modulus of the adhesive increases and adhesive thickness increases. In addition, Experiments to measure the strains and joint strengths were compared with the calculated results. The calculated results were in fairly good agreements with the experimental results.

Stress Analysis of Butt Adhesive Joints of Dissimilar Hollow Cylinders Under Impact Tensile Loadings

2002 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yoshihito Suzuki ◽  
Shoichi Kido
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Young's Modulus ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Inside Diameter ◽  
Adhesive Thickness ◽  
Hollow Cylinders ◽  
Stress Variations ◽  
The Impact

The stress variations in butt adhesive joints of dissimilar hollow cylinders under impact tensile loadings are analyzed in elastic and elasto-plastic deformation using a finite element method. The FEM code employed is DYNA3D. The effect of Young’s modulus of the adhesive, adhesive thickness and the inside diameter of the hollow cylinders and Young’s modulus ratio between dissimilar adherends on the stress variations at the interfaces are examined. In addition, a process in rupture at the interface of the joint is analyzed. The stress distributions in the joints under static loadings are also analyzed by an FEM. The characteristics of the stress variations in the joints under impact loadings are compared with those in the joints under the static loadings. Also, the joint strenths under impact loadings are estimated. As the results, it is found that the maximum value of the maximum principal stress σl occurs at the outside of the interface. It is also found that the maximum principal stress σl at the interface decreases as the inside diameter of the hollow cylinders increases. The characteristics of the joints subjected to the impact loadings are found to be opposite to those subjected to the static loadings. In addition, the experiments were carried out to measure the strain response of the butt adhesive joints under impact tensile loads using strain gauges. Furthermore, the joint strengths under impact loadings were measured. Fairly good agreements are observed between the numerical and the measured results.

Finite Element Stress Response Analysis of Stepped-Lap Adhesive Joints of Similar Adherends Under Impact Tensile Loadings

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Takahiro Oomori ◽  
Kohei Ichikawa ◽  
Shoichi Kido
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Adhesive Joints ◽  
Response Analysis ◽  
Stress Distributions ◽  
Maximum Value ◽  
Adhesive Thickness ◽  
Stress Variations ◽  
The Impact

The stress variations and stress distributions in stepped-lap adhesive joints of similar adherends under impact tensile loadings were analyzed in elastic range using three-dimensional finite element method (DYNA3D). The impact loadings were applied to the lower adherend by dropping a weight. The stress distributions in stepped-lap adhesive joints of similar adherends under static tensile loadings were also analyzed using FEM (MARC). The effects of Young’s modulus of the adherends, the adhesive thickness, and a number of steps in the adherends on the stress variations and the stress distributions at the interfaces between the adherends and the adhesive were examined under both impact and static loadings. As the results, it was found that (1) the maximum value of the maximum principal stress σ1 occured at the outside edge of the butted interface between the adhesive and the lower adherend to which impact loadings were applied; (2) The maximum value of stress σ1 increased as Young’s modulus of the adherends increased; (3) The maximum value of stress σ1 increased as the adhesive thickness decreased, and it increased at the butted parts of joints as the adhesive thickness decreased. The maximum value of stress σ1 increased at the lapped parts of joints as the adhesive thickness increased; (4) The maximum value of stress σ1 increased as the numbers of steps in the adherends increased. The characteristic of the joints under static loadings were also clarified. In addition, the experiments to measure the strain response of joints subjected to impact tensile loadings were carried out using strain gauges. A fairly good agreement was found between the numerical and the measured results concerning the strain responses.

Investigation of Stress Wave Propagation in Brain Tissues Through the Use of Finite Element Method

2010 ◽  
Author(s):  
Biaobiao Zhang ◽  
W. Steve Shepard ◽  
Candace L. Floyd
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Brain Injury ◽  
Stress Wave ◽  
Brain Research ◽  
Complex Structure ◽  
Stress Wave Propagation ◽  
Wave Loads ◽  
The Impact ◽  
The Brain

Because axons serve as the conduit for signal transmission within the brain, research related to axon damage during brain injury has received much attention in recent years. Although myelinated axons appear as a uniform white matter, the complex structure of axons has not been thoroughly considered in the study of fundamental structural injury mechanisms. Most axons are surrounded by an insulating sheath of myelin. Furthermore, hollow tube-like microtubules provide a form of structural support as well as a means for transport within the axon. In this work, the effects of microtubule and its surrounding protein mediums inside the axon structure are considered in order to obtain a better understanding of wave propagation within the axon in an attempt to make progress in this area of brain injury modeling. By examining axial wave propagation using a simplified finite element model to represent microtubule and its surrounding proteins assembly, the impact caused by stress wave loads within the brain axon structure can be better understood. Through conducting a transient analysis as the wave propagates, some important characteristics relative to brain tissue injuries are studied.

Dynamic Ultimate Strength Characteristics of Stiffened Plates Subjected to the In-Plane Impact Load and Lateral Pressure

2021 ◽  
Author(s):  
Qiang Zhong ◽  
De-yu Wang
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Lateral Pressure ◽  
Impact Load ◽  
Strength Characteristics ◽  
Stiffened Plates ◽  
Strength Theory ◽  
Explicit Finite Element ◽  
Static Conditions ◽  
The Impact

Abstract Dynamic capacity is totally different from quasi-static capacity of ship structural components, although most ultimate strength analyses at present by researchers are performed under quasi-static conditions. To investigate the dynamic ultimate strength characteristics, the dynamic ultimate strength analyses of stiffened plates subjected to impact load were studied based on a 3-D nonlinear explicit finite element method (FEM) in this paper. The impact load in the present work is characterized as a half-sine function. A series of nonlinear finite element analyses are carried out using Budiansky-Roth (B-R) criterion. The influence of impact durations, model ranges, boundary conditions, initial imperfections and impact loads on the dynamic ultimate strength of stiffened plates are discussed. In addition, the ultimate strength of stiffened plates under the in-plane impact combined with lateral pressure was also calculated, which shows lateral pressure has a negligible effect on the dynamic ultimate strength of stiffened plates subjected to the impact load with short durations. Other important conclusions can be obtained from this paper, which are useful insights for the development of ultimate strength theory of ship structures and lay a good foundation for the study of dynamic ultimate strength in the future.

Rails Deformation Pattern in Frontal Impact

2002 ◽  
Author(s):  
Joseph Hassan ◽  
Guy Nusholtz ◽  
Ke Ding
Keyword(s):  
Wave Propagation ◽  
Real World ◽  
Stress Waves ◽  
Stress Wave Propagation ◽  
Deformation Pattern ◽  
Frontal Impact ◽  
Rigid Barrier ◽  
Final Deformation ◽  
Deformation Patterns ◽  
The Impact

During a vehicle crash stress waves can be generated at the impact point and propagate through the vehicle structure. The generation of these waves is dependent, in general, on the crash type and, in particular, on the impact contact characteristics. This has consequences with respect to different crash barrier interfaces for vehicle evaluation. The two barriers most commonly used to evaluate the response of a vehicle in a frontal impact are the rigid barrier and the offset deformable barrier. They constitute different crash modes, full frontal and offset. Consequently it would be expected that there are different deformation patterns between the two. However, an additional possible contributor to the difference is that an impact into a rigid barrier generates waves of significantly greater stress than impacts with the deformable one. If stress waves are a significant component of real world final deformation patterns then, the choice of barrier interface and its effective stiffness is critical. To evaluate this conjecture, models of two types of rails each undergoing two different types of impacts, are analyzed using an explicit dynamic finite element code. Results show that the energy perturbation along the rail depends on the barrier type and that the early phase of wave propagation has very little effect on the final deformation pattern. This implies that in the real world conditions, the stress wave propagation along the rail has very little effect on the final deformed shape of the rail.

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