Smoothed particle hydrodynamic analysis

This problem contains basic test cases for one or more Abaqus elements and features.

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ProductsAbaqus/Explicit

Bird strike on an airplane engine blade

Elements tested

PC3D

Problem description

This verification problem tests the ability of PC3D elements to describe the impact of a bird on an airplane engine blade. The rotating airplane engine blade is subjected to an impact with a cylindrical model of a flying bird using the smoothed particle hydrodynamic (SPH) technique. After the impact, the bird completely disintegrates and splashes over the surface of the engine blade. A similar approach can be used for modeling severe deformations of thin shell structures impacted by objects moving with high velocity.

Model:

This model analyzes the impact interaction between a flying object and a rotating airplane engine blade. The airplane engine blade is modeled using 960 S4RS shell elements. A set of nodes closer to the turbine hub are kinematically coupled to a reference node situated at the center of the hub. A constant angular velocity of 5.466×102 rad/s is applied at the reference node about the z-axis. The engine blade is modeled with an elastic-plastic material with Young's modulus E=210 GPa, Poisson's ratio ν=0.3, density ρ=4.0×103 kg/m3, and isotropic hardening. The flying bird is modeled using 4160 PC3D elements. The bird material is modeled using a tabular equation of state (EOS) material with a tensile failure strength of 94 MPa and a density of ρ=1.0×103 kg/m3. The radius of the cross-section of the cylinder modeling the bird is 0.04 m, and the height of the cylinder is 0.076 m. The contact interaction between the surfaces of the bird object and the shell structure is defined through contact inclusions.

The initial configuration of the model is shown in Figure 1.

An intermediate deformed configuration of the airplane engine blade and the bird system is shown in Figure 2.

Results and discussion

After the impact, the blade undergoes severe deformation. The edges of the thin shell structure close to the impact area become warped. The bird object completely disintegrates and splashes over the surface of the engine blade. This test problem verifies the capability of the SPH technique to model large deformations and failure of fluid-like materials. Contact interaction between the PC3D and the S4RS elements is also verified.

Figures

Figure 1. Undeformed configuration of the airplane engine blade and the bird system.

Figure 2. Deformed configuration of the airplane engine blade and the bird system.

Bird strike on an airplane engine blade using conversion

Elements tested

C3D8R

PC3D

Problem description

This verification problem tests the ability of reduced-integration continuum elements (C3D8R) elements to convert to SPH particles as deformation progresses during the impact of a bird on an airplane engine blade.

Model:

Overall the model, the material properties, and the loading conditions are the same as in Bird strike on an airplane engine blade. The only exception is that the bird is first modeled with C3D8R elements rather than with PC3D elements. A strain-based criterion is used to convert each continuum element to eight SPH particles. The contact interaction between the internally generated particles and the shell structure is defined automatically from the user-defined contact inclusions.

The initial configuration of the model is shown in Figure 3.

An intermediate deformed configuration of the airplane engine blade and the bird system is shown in Figure 4.

Results and discussion

After the impact, the blade undergoes severe deformation. Continuum elements convert progressively as the specified maximum principal strain is reached in each element. The edges of the thin shell structure near the impact area become warped.

Figures

Figure 3. Undeformed configuration of the airplane engine blade and the bird modeled with continuum elements.

Figure 4. Deformed configuration of the airplane engine blade and the bird as the conversion of the continuum elements progresses.

Water splash in a square pan

Elements tested

PC3D

Problem description

This problem tests the ability of PC3D elements to model impact and mixing of two liquid bodies of the same material. A spherical water drop falls into a square container containing water under gravitational forces. The water drop moves down toward the water in the container and, after splashing, settles to an equilibrium state within the container. The container is modeled using five shell elements. In this test problem mass scaling and bulk modulus reduction are used to increase the value of the stable time increment. Since compressibility does not play a significant role in this analysis, this modeling choice should not affect the results significantly.

Model:

This model analyzes the impact and mixing of two liquids with the same material properties. The spherical liquid drop and the liquid in the container are modeled using 3544 and 9000 PC3D elements, respectively. Both liquids are defined using an EOS material of type USUP modeling a linear equation of state. The parameters used in this material model are c0=0.111803398875 mm/s, s=0.0, and Γ0=0.0. To increase the stable time increment, the density of the liquid is artificially defined as ρ=1 tonne/mm3. The height of the container is 5 mm. The horizontal cross-section of the container has a square shape with a side length of 15 mm. The lateral and bottom walls of the container are modeled as S4R shell elements. The contact interaction between the liquid and the shell structure is defined through contact inclusions.

The initial configuration and an intermediate configuration are shown in Figure 5 and Figure 6.

Results and discussion

This test problem verifies the capability of the SPH technique in Abaqus/Explicit to model the impact and mixing processes of two liquid materials. The mass scaling technique, which drastically increases the stable time increment in this dynamic analysis, is also verified.

Figures

Figure 5. The initial configuration of a water drop and a water-filled square pan.

Figure 6. An intermediate configuration of the water drop splashing in a water-filled square pan.

Splashing of a figurehead

Problem description

This problem tests the impact interaction between PC3D elements and a rigid solid structure with a complex curved surface. A block of liquid is moved toward a figurehead and splashes over its surface. The cohesion force used in this model helps maintain some tensile strength for the liquid material during splashing.

Model:

This model analyzes the impact interaction between a liquid modeled using the SPH technique and a rigid solid structure. The block of liquid is modeled using 53040 PC3D elements. The material model of the liquid used is an EOS material of type USUP modeling a linear equation of state. The material parameters used are c0=1.5×106 mm/s, s=0.0, and Γ0=0.0. A failure strength of 2 MPa is defined for this EOS type material. To model the figurehead, 4084 R3D3 rigid elements are used. The initial velocity of the liquid is 3000 mm/s along the y-direction toward the figurehead. The confining box has a dimension of 800 mm × 800 mm × 500 mm, and it is modeled using 48 R3D4 rigid elements. The contact interaction between the liquid and the surfaces of the figurehead and the confining box is defined through contact inclusions with the no-friction surface interaction.

The initial and intermediate configurations are shown in Figure 7 and Figure 8.

Results and discussion

This problem verifies the capability of the SPH technique to model the impact interaction between a block of liquid and a rigid body with a complex surface topography. The effects of the cohesion force modeled for the SPH particles are also tested.

Figures

Figure 7. The initial configuration of a block of water and a figurehead.

Figure 8. An intermediate configuration of water splashing on a figurehead.

Melting of a figurehead statue

Problem description

This problem tests the ability of PC3D elements to model large deformation and failure of an isotropic elastic-plastic material upon an abrupt change of temperature. A figurehead statue, modeled with temperature-dependent material properties, begins to melt as the temperature suddenly jumps to a higher value. The contact interaction between the SPH related particles and the rigid elements is also tested.

Model:

This problem analyzes the temperature-related failure of a figurehead statue modeled using the SPH technique. The figurehead statue is modeled using 8252 PC3D elements, and it is characterized by a temperature-dependent elastic-plastic material mode via field variable dependencies. The Young's modulus, E, is equal to 2 MPa when the non-dimensional field variable is equal to 1.0, and it is equal to 0.8 MPa when this variable changes to 2.0. The dependence of the plastic properties on the temperature is given via tabular data. The density of the material is defined as ρ=1.0×10-8 tonne/mm3. Fifty R3D4 elements are used to model the bottom and the lateral walls. The melting process of the figurehead statue is accelerated after a sudden rise of the temperature during the dynamic analysis. The contact interaction between the solid statue and the rigid wall is defined through contact inclusions.

The initial and intermediate configurations are shown in Figure 9 and Figure 10.

Results and discussion

This problem verifies the application of the SPH technique to model the large deformation and failure of a temperature-dependent isotropic elastic-plastic material. The contact interaction between this material modeled using SPH particles and the rigid bodies is also tested.

Figures

Figure 9. The initial configuration of the figurehead statue.

Figure 10. Velocity vector plot of an intermediate configuration for the melted figurehead statue.

Smashing of a figurehead

Problem description

This problem tests the ability of PC3D elements to model the impact of a figurehead on solid walls. The figurehead, modeled as a toothpaste-like viscous material, is smashed onto solid walls. After the impact, the figurehead is completely crashed on the lateral wall and then flows down onto the bottom wall under gravitational forces. The contact interaction between the SPH related particles and the rigid elements is also tested.

Model:

This model analyzes the impact interaction between a figurehead and solid walls. The figurehead is modeled using 8252 PC3D elements. The material model used for this figurehead is an EOS material of type USUP modeling a linear equation of state. The material parameters used are c0=1.405×105, s=0.0, and Γ0=0.0. A linear viscous shear behavior is defined for this hydrodynamic material through tabular data. A tensile failure strength of 10 MPa is also defined for this material. The density of the figurehead is set to ρ=9×10-10 tonne/mm3. Fifty R3D4 elements are used to model the bottom and the lateral walls. The initial velocity of the figurehead is set to 1.0×103 mm/s toward the lateral wall. The figurehead then follows a parabolic path under gravitational forces until it strikes the wall. After the impact, the figurehead is smashed onto the lateral wall and then crashes into the corner edge because of complete material failure. The contact interaction between the figurehead and the rigid wall is defined through contact inclusions using rough friction to describe the frictional interactions.

The initial configuration and an intermediate configuration of the figurehead and the rigid walls are shown in Figure 11 and Figure 12.

Results and discussion

This problem verifies the application of the SPH technique to model the failure of a cohesive linear viscous material. The contact interaction between this material and a rigid wall is also tested.

Figures

Figure 11. The initial configuration of a figurehead.

Figure 12. Velocity vector plot of an intermediate configuration for the figurehead after being smashed on a wall.

Projectile impact on a plate

Elements tested

PC3D

Problem description

This verification problem tests the ability of PC3D elements to handle large deformations and failure of a rate-dependent elastic-plastic material upon impact of a high-speed projectile. A solid plate, of which the central part is modeled using the SPH technique, is subjected to an impact by a high-velocity cylindrical rigid object. After the impact, the part close to the center of the plate first undergoes a large deformation and then breaks apart. Eventually, the projectile perforates the plate.

Model:

This model analyzes the impact interaction between a high-velocity projectile and a solid plate. The solid plate has a dimension of 400 mm × 400 mm × 12 mm. A circular part with a radius of 100 mm in the center of the plate is modeled using 102726 PC3D elements, and the remaining part of the plate is modeled using 9312 C3D8R elements. The length and radius of the cylindrical rigid solid projectile are 25 mm and 8.4 mm, respectively. The initial speed of the projectile is set to 1000 m/s. The material used for the plate is a steel with Young's modulus E=2.1×105 MPa, Poisson's ratio ν= 0.3, and density ρ=7.8×10-9 tonne/mm3. The plate is modeled as an elastic-plastic material with rate-dependent hardening. Ductile and shear damage are evolved based on an energy criterion. The interaction between the rigid projectile and the solid plate is defined using frictional contact with a friction coefficient of 0.3.

The initial configuration of the model is shown in Figure 13, and an intermediate deformed configuration cross-section is shown in Figure 14.

Results and discussion

After the impact, the center part of the plate first undergoes a large deformation and then breaks into pieces. In the end, the projectile penetrates the plate completely. This problem verifies the ability of the SPH technique to model large deformation and failure of rate-dependent elastic-plastic materials. Contact interaction between the PC3D elements and solid elements is also verified.

Figures

Figure 13. The initial configuration of the solid plate and projectile.

Figure 14. Contour plot of Mises stress for the solid plate subjected to an impact of a projectile.