Most of the buffer packaging materials used today are non-linear, that is to say, the buffer packaging system constitutes a mechanical model of nonlinear forced vibration, and in the process of transport, the excitation force is mostly a random process. So far, there is no universally feasible method for the analysis and solution of the general nonlinear forced vibration system in mathematics. Therefore, a variety of approximate methods for solving have emerged. These approximate methods have better results in their respective applications, but most methods are more complicated in general packaging engineering applications. In contrast, the simple buffer packaging design method has its unique role. However, the simple buffer design method is also an approximate method. In order to ensure the reliability of the buffer packaging design or analysis and evaluation using this design method, the following problems should be noted.
Problem 1, the reliability of analysis and evaluation In the simple and rapid buffer packaging design method, the basic basis for use is the transmission rate, because the percentage of vibration isolation is also calculated based on the transmission rate, while the transmission rate is based on a linear system with a single degree of freedom. Harmonic excitation analysis, obviously, it and the actual buffer packaging system design calculations are very different. The first is the incentive method. As mentioned above, in the actual transportation process, the packaging system is generally subjected to random excitation, the amplitude and frequency of the excitation are all changed, and the response is also random. In this case, The buffering effect is naturally different from the case of the excite-wave excitation. However, in many cases, due to the filtering effect of the buffer packaging system itself, the response tends to a narrow-band process, and the vehicle itself also has such an effect, when the random vibration bandwidth When it is very narrow and the amplitudes are basically the same, it is feasible to treat the excitation as simple harmonic excitation within the scope of practical engineering application. The second is the nonlinear problem. Strictly speaking, nonlinear systems do not have an "inherent" frequency. And sometimes non-linear, even small, can make a big change in the response of the system. In the simple buffer packaging design method, security factors have been taken into account for the factors that have changed the "inherent" frequency. However, the great changes in the nature of the system response caused by non-linearity still require attention. This is mainly related to the stability of the movement. For example, a periodic motion with a nonlinear restoring force under harmonic excitation is much more complicated than the forced vibration of a linear system. The most important primary harmonic response, not only does not have a definite resonance frequency like a linear system, but at the same excitation frequency, it may correspond to periodic solutions with different amplitudes, of which only one is stable, while others are stable. It is unstable, which causes the response to jump, that is, the movement suddenly changes from an amplitude to an amplitude, and this change does not have an intermediate smooth transition and appears as a sudden jump or jump. In addition, in addition to the primary harmonic response close to the natural frequency ω, there is a subharmonic response that is an integral multiple of the natural frequency or a fractional fractional harmonic response, which makes it possible to cause some of the package contents. The resonant response of these parts or structures causes damage.
Problem Two, Test Problems One of the salient advantages of using a simple quick-buffer package design method is that testing is simple and easy to implement. It only needs to obtain the load of the known buffer packaging structure—the static displacement relation curve, which is much easier than the cushion factor of the buffer packaging material.
Question 3, the establishment of a buffer design database
Problem 1, the reliability of analysis and evaluation In the simple and rapid buffer packaging design method, the basic basis for use is the transmission rate, because the percentage of vibration isolation is also calculated based on the transmission rate, while the transmission rate is based on a linear system with a single degree of freedom. Harmonic excitation analysis, obviously, it and the actual buffer packaging system design calculations are very different. The first is the incentive method. As mentioned above, in the actual transportation process, the packaging system is generally subjected to random excitation, the amplitude and frequency of the excitation are all changed, and the response is also random. In this case, The buffering effect is naturally different from the case of the excite-wave excitation. However, in many cases, due to the filtering effect of the buffer packaging system itself, the response tends to a narrow-band process, and the vehicle itself also has such an effect, when the random vibration bandwidth When it is very narrow and the amplitudes are basically the same, it is feasible to treat the excitation as simple harmonic excitation within the scope of practical engineering application. The second is the nonlinear problem. Strictly speaking, nonlinear systems do not have an "inherent" frequency. And sometimes non-linear, even small, can make a big change in the response of the system. In the simple buffer packaging design method, security factors have been taken into account for the factors that have changed the "inherent" frequency. However, the great changes in the nature of the system response caused by non-linearity still require attention. This is mainly related to the stability of the movement. For example, a periodic motion with a nonlinear restoring force under harmonic excitation is much more complicated than the forced vibration of a linear system. The most important primary harmonic response, not only does not have a definite resonance frequency like a linear system, but at the same excitation frequency, it may correspond to periodic solutions with different amplitudes, of which only one is stable, while others are stable. It is unstable, which causes the response to jump, that is, the movement suddenly changes from an amplitude to an amplitude, and this change does not have an intermediate smooth transition and appears as a sudden jump or jump. In addition, in addition to the primary harmonic response close to the natural frequency ω, there is a subharmonic response that is an integral multiple of the natural frequency or a fractional fractional harmonic response, which makes it possible to cause some of the package contents. The resonant response of these parts or structures causes damage.
Problem Two, Test Problems One of the salient advantages of using a simple quick-buffer package design method is that testing is simple and easy to implement. It only needs to obtain the load of the known buffer packaging structure—the static displacement relation curve, which is much easier than the cushion factor of the buffer packaging material.
Question 3, the establishment of a buffer design database