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Q1. High wave bandwidth waveform principle explanation.
A1:
(A) is the waveform at resonance frequency, (b) is the waveform of the sub-resonance frequency, and (c) is the waveform of the resonant frequency. ) Are the waveforms of high wave frequency (high frequency wave), these three kinds of waveforms belong to the case of ω <ω n, and the residual stress elimination effect of wavelet frequency is the best. Because of the relationship between the large wave and the wavelet, (2), the amplitude of the two waves will be the same when ω ≈ ω n, as shown in Figure (d), when the ω wave is gradually increased, , The formation of heavy blows, the experiment also find the blower waveform as shown in Figure (e), ω if further increase, then the large wave into a simple harmonic vibration caused. (C) is the high wave bandwidth, the most close to ω ≈ ω n case, so the highest wave width of the wave, the residual stress to eliminate the best, reaching 38.8%. We can see that the homogeneous solution of this high-frequency wave is the equation of the sub-wave, which can be interpreted as the displacement equation caused by the free vibration of the metal material. This is the phenomenon of spontaneous stretching and compression in the material, based on the vibration Theory to consider the nature of the most primitive wave "waveform" as a parameter, by the vibration stress to eliminate the residual stress mechanism of the waveform point of view, the oscilloscope measured out of the three waveforms (resonant, secondary resonance, high wave bandwidth) (The frequency is lower) and the sub-wave (higher frequency), the main wave represents the physical meaning of the external force (motor) caused by vibration waves, and sub-wave of the physical meaning of the material produced by the spontaneous , That is, the amplitude of the waveform of the homogeneous solution of the high-wave bandwidth, that is, the maximum amplitude of the sub-wave is excited by the low-frequency vibration. According to the above theory, it will be possible to know that the high wave bandwidth (high frequency wave - graph (c) waveform) has the best effect of eliminating residual stress. (High frequency wave charta、b、c) ← click to open the link
(A) is the waveform at resonance frequency, (b) is the waveform of the sub-resonance frequency, and (c) is the waveform of the resonant frequency. ) Are the waveforms of high wave frequency (high frequency wave), these three kinds of waveforms belong to the case of ω <ω n, and the residual stress elimination effect of wavelet frequency is the best. Because of the relationship between the large wave and the wavelet, (2), the amplitude of the two waves will be the same when ω ≈ ω n, as shown in Figure (d), when the ω wave is gradually increased, , The formation of heavy blows, the experiment also find the blower waveform as shown in Figure (e), ω if further increase, then the large wave into a simple harmonic vibration caused. (C) is the high wave bandwidth, the most close to ω ≈ ω n case, so the highest wave width of the wave, the residual stress to eliminate the best, reaching 38.8%. We can see that the homogeneous solution of this high-frequency wave is the equation of the sub-wave, which can be interpreted as the displacement equation caused by the free vibration of the metal material. This is the phenomenon of spontaneous stretching and compression in the material, based on the vibration Theory to consider the nature of the most primitive wave "waveform" as a parameter, by the vibration stress to eliminate the residual stress mechanism of the waveform point of view, the oscilloscope measured out of the three waveforms (resonant, secondary resonance, high wave bandwidth) (The frequency is lower) and the sub-wave (higher frequency), the main wave represents the physical meaning of the external force (motor) caused by vibration waves, and sub-wave of the physical meaning of the material produced by the spontaneous , That is, the amplitude of the waveform of the homogeneous solution of the high-wave bandwidth, that is, the maximum amplitude of the sub-wave is excited by the low-frequency vibration. According to the above theory, it will be possible to know that the high wave bandwidth (high frequency wave - graph (c) waveform) has the best effect of eliminating residual stress. (High frequency wave charta、b、c) ← click to open the link
Q2. Energy view of the difference row movement
A2: According to the theory of differential row movement, consider an object due to plastic deformation caused by processing, and therefore there is residual stress inside the situation. Figure 1. There is a row of rows between row A and row B, and when the plastic deformation caused by vibration occurs, the difference is shifted leftward and the atoms of row A move from the position in Figure 1 (a) to Figure 1 (A) is moved to the position of the dotted line, and then moved from the position of the dotted line to the position of the dotted line, since the position of A is directly shifted from (a) to (b) Figure (b) the position of A.
(差排移動分解的示意圖) ←Click to open the link.
In terms of energy, this is the easiest way to move. When the residual stress caused by the atomic ectopic elimination, the vibration force is not enough to provide the atomic movement to the next vacancy in other non-fcc crystal system material, but also because the oscillation can not make a row of a complete branch of the Burger's vector The formation of the above phenomenon.
In the object with residual stress, as shown in Figure 2, the residual stress is M before the vibration and H is the minimum requirement for the A atom to move to the dotted line position, and the stress provided by the vibration When the residual stress can surpass H, the A atom can fall across the barrier between the atoms and fall to the low point L, so that the residual stress can be released and the residual stress released is ML. The atomic arrangement is as shown in Figure 1. (b ), Because the A atom has been in the lowest energy position, unless the supply of HL stress can not make A atoms continue to move, and when the stress has been released, the vibration force is far less than this, so A row of atoms will not be able to move, Forming a major difference row to form two partial rows. Figure 1 (a), (b) shows the increase in the stack.
esidual stress + vibration stress> stress reduction
The same time as.
So that it can eliminate more residual stress.
After the main difference row can reduce the strain energy, on the other hand, the energy of the row can be reduced, because its energy is proportional to the square of Burger's vector, on the other hand when the main difference row after the two parts of the poor row too close, due to The repulsive force between the rows will cause the two rows to move in the opposite direction, which is an extended dislocation until the repulsive force between the two rows is lower than the force that makes the difference row move. Will be stopped, this body involves the material stacking energy, which can explain why the same crystal structure of the material to the vibration stress to eliminate the reaction has no small difference, but because of the power of external vibration, even if the row of repulsive force is less than The force required for movement is still likely to meet the minimum force required for movement, so the atoms are rearranged by the movement of the rows to reduce the strain inside the material.
殘留應力釋放之能量關係圖.png ←Click to open the link.
(差排移動分解的示意圖) ←Click to open the link.
In terms of energy, this is the easiest way to move. When the residual stress caused by the atomic ectopic elimination, the vibration force is not enough to provide the atomic movement to the next vacancy in other non-fcc crystal system material, but also because the oscillation can not make a row of a complete branch of the Burger's vector The formation of the above phenomenon.
In the object with residual stress, as shown in Figure 2, the residual stress is M before the vibration and H is the minimum requirement for the A atom to move to the dotted line position, and the stress provided by the vibration When the residual stress can surpass H, the A atom can fall across the barrier between the atoms and fall to the low point L, so that the residual stress can be released and the residual stress released is ML. The atomic arrangement is as shown in Figure 1. (b ), Because the A atom has been in the lowest energy position, unless the supply of HL stress can not make A atoms continue to move, and when the stress has been released, the vibration force is far less than this, so A row of atoms will not be able to move, Forming a major difference row to form two partial rows. Figure 1 (a), (b) shows the increase in the stack.
esidual stress + vibration stress> stress reduction
The same time as.
So that it can eliminate more residual stress.
After the main difference row can reduce the strain energy, on the other hand, the energy of the row can be reduced, because its energy is proportional to the square of Burger's vector, on the other hand when the main difference row after the two parts of the poor row too close, due to The repulsive force between the rows will cause the two rows to move in the opposite direction, which is an extended dislocation until the repulsive force between the two rows is lower than the force that makes the difference row move. Will be stopped, this body involves the material stacking energy, which can explain why the same crystal structure of the material to the vibration stress to eliminate the reaction has no small difference, but because of the power of external vibration, even if the row of repulsive force is less than The force required for movement is still likely to meet the minimum force required for movement, so the atoms are rearranged by the movement of the rows to reduce the strain inside the material.
殘留應力釋放之能量關係圖.png ←Click to open the link.
Q3. What situations need to eliminate residual stress?
A3:
🔯 constructs complex workpieces.
🔯 work at low temperature, shock or vibration load.
🔯 machining accuracy or dimensional stability requirements of the workpiece.
Chemical equipment, etc., there are stress corrosion possible workpiece
🔯 hardened material
🔯 for annealing, quenching or crying before
🔯 constructs complex workpieces.
🔯 work at low temperature, shock or vibration load.
🔯 machining accuracy or dimensional stability requirements of the workpiece.
Chemical equipment, etc., there are stress corrosion possible workpiece
🔯 hardened material
🔯 for annealing, quenching or crying before
Q4. Elimination of residual stress principle
A4: in the form of vibration to the workpiece with additional shear stress, thereby reducing and homogenizing the residual stress within the workpiece, so that the accuracy of a stable method, the principle of the use of oscillation force and residual stress superimposed on the material internal stress More than the drop point caused by the material of small plastic deformation, by repeated oscillation to slip the grain and reduce the material within the strain energy.
🎈The use of shear stress to promote the poor row of movement.
🎈Fluctuation is the best way to produce alternating shear stresses.
🎈The shorter the wavelength, the greater the amplitude, the greater the shear stress, the higher the energy density, the better the effect.
🎈The use of shear stress to promote the poor row of movement.
🎈Fluctuation is the best way to produce alternating shear stresses.
🎈The shorter the wavelength, the greater the amplitude, the greater the shear stress, the higher the energy density, the better the effect.
Q5. Effective vibration elimination of residual stress mode
A5: the use of external shock wave to stimulate the internal maximum fluctuations, resulting in poor row to promote the maximum shear stress, to achieve the effect of stress relief. Each material, shape, weight has its own special fluctuations.
Q6. Improper vibration stress eliminates construction
A6: giant vibration, the smallest micro-vibration
Causing material fatigue
The impact caused by local forces too much will be injured!
Causing material fatigue
The impact caused by local forces too much will be injured!
Q7. Heat treatment of the troubles
A7:
• Material: Stainless steel - no solution
• deformation - must
• Mechanical properties change - soften
• huge pieces - restrictions
Site site - limit
• Oxidation - to be overcome
• Processing costs - high
• Material: Stainless steel - no solution
• deformation - must
• Mechanical properties change - soften
• huge pieces - restrictions
Site site - limit
• Oxidation - to be overcome
• Processing costs - high
Q8. Types of residual stress
A8:
• Thermal stress: Relieves cumulative shrinkage
• Phase change stress: rapid expansion
• Condensation shrinkage stress: thermal cracking
• Plastic processing stress: grain deformation
• Thermal stress: Relieves cumulative shrinkage
• Phase change stress: rapid expansion
• Condensation shrinkage stress: thermal cracking
• Plastic processing stress: grain deformation
Q9. Residual stress generated by the process!
A9:
Welding: thermal stress, phase change stress, solidification shrinkage stress
Drilling: thermal stress, plastic working stress
Mechanical Straightening: Plastic Working Stress
Thermal stress: thermal stress, phase change stress
Exposure: slightly to the stress
Sandblasting: stress depends on sand
Welding: thermal stress, phase change stress, solidification shrinkage stress
Drilling: thermal stress, plastic working stress
Mechanical Straightening: Plastic Working Stress
Thermal stress: thermal stress, phase change stress
Exposure: slightly to the stress
Sandblasting: stress depends on sand
Q10. History and side effects of vibration technology
A10: The origin of oscillating technology Since the 1950s, the US Navy, the Germans used resonance to test the stability of the hull and aircraft structure, and accidentally found that vibration can also eliminate the residual stress inside the material. To eliminate the residual stress there are many benefits, the biggest advantage is not too much material will not be deformed, others, such as no longer like a large heat treatment furnace must be tens of millions of times to get the equipment, processing time can be significantly reduced and no high temperature oxidation And in the 1960s, the study of vibration elimination of residual stress has been sprung up, but there is no standard for the measurement of residual stress, although the oscillation is true, and the vibration of the large-scale workpiece can be eliminated. Can eliminate the residual stress, but its effect is different, it is questionable, and did not get a lot of reverberation, not to mention there are many studies that the technology not only did not achieve the desired effect there are serious side effects, generally most often attacked Is the fatigue damage and mechanical strength deterioration, so how to achieve the best results and to avoid the side effects, is the focus of this study. So the "high frequency wave" under the environment will not cause fatigue damage.
Q11. Is there any adverse effect on the person standing on the workpiece when the vibration stress is removed
A11: The vibration frequency used in the construction is "high frequency wave", and this wave size determines the energy of the lattice differential movement (stress release), so when there is a medium (person or other object) on the vibration source (construction work) The size of this energy and then the impact of the effect.
Q12. Is there any adverse effect on the necessary ancillary equipment on the workpiece when the vibration stress is removed.
A12: no adverse effects (but to consider the "vibration loose" safety), vibration stress elimination must avoid the sub-resonance and resonance point (maximum frequency of vibration), so "high-frequency wave" operating environment will not cause anti- The destruction of the produce.
Q13. Is there any restriction on the size of the workpiece for vibration stress elimination?
A13: The general scope of application is in accordance with the "vibration wave (energy wave)" transmission range, when the vibration wave is transferred to the point there is relative energy can be stress relief, and according to the vibrator radius of 2M for effective transmission Range, when greater than the diameter of 2M need to be divided into multi-point operation.
(Within the radius of 2M within the vibrator for effective transmission range, due to the structural structure of steel and vary, such as the rigid structure is relatively weak when the transmission range will be larger, otherwise the structural steel density is high when the range will be smaller)
(Within the radius of 2M within the vibrator for effective transmission range, due to the structural structure of steel and vary, such as the rigid structure is relatively weak when the transmission range will be larger, otherwise the structural steel density is high when the range will be smaller)
