Laser machining is one of most widely used technologies nowadays and becoming a hot industry as well. At the same time, many kinds of carbon fiber material have been used in different area, such as sports products, transportation, microelectronic industry and so on. Moreover, there is lack of the combination research on the laser interaction with Carbon Fiber Reinforced Polymer (CFRP) material with simulation method. In this paper, the temperature status of long pulse laser interaction with CFRP will be simulated and discussed. Firstly, a laser thermal damage model has been built considering the heat conduction theory and thermal-elasto-plastic theory. Then using COMSOL Multiphysics software to build the geometric model and to simulate the mathematic results. Secondly, the functions of long pulse laser interaction with CFRP has been introduced. Material surface temperature increased by time during the laser irradiating time and the increasing speed is faster when the laser fluence is higher. Furthermore, the peak temperature of the center of material surface is increasing by enhanced the laser fluence when the pulse length is a constant value. In this condition, both the ablation depth and the Heat Affected Zone(HAZ) is larger when increased laser fluence. When keep the laser fluence as a constant value, the laser with shorter pulse length is more easier to make the CFRP to the vaporization material. Meanwhile, the HAZ is becoming larger when the pulse length is longer, and the thermal effect depth is as the same trend as the HAZ. As a result, when long pulse laser interaction with CFRP material, the thermal effect is the significant value to analysis the process, which is mostly effect by laser fluence and pulse length. For laser machining in different industries, the laser parameter choose should be different. The shorter pulse length laser is suitable for the laser machining which requires high accuracy, and the longer one is better for the deeper or larger ablation holes.
The research focused on the effect of delay time in combined pulse laser machining on the material temperature field. Aiming at the parameter optimization of pulse laser machining aluminum alloy, the combined pulse laser model based on heat conduction equation was introduced. And the finite element analysis software, COMSOL Multiphysics, was also utilized in the research. Without considering the phase transition process of aluminum alloy, the results of the numerical simulation was shown in this paper. By the simulation study of aluminum alloy’s irradiation with combined pulse, the effect of the change in delay time of combined pulse on the temperature field of the aluminum alloy and simultaneously the quantized results under the specific laser spot conditions were obtained. Based on the results, several conclusions could be reached, the delay time could affect the rule of temperature changing with time. The reasonable delay time controlling would help improving the efficiency. In addition, when the condition of the laser pulse energy density is constant, the optimal delay time depends on pulse sequence.
According to the heat conduction equation, thermoelastic equation and boundary conditions of finite, using the finite
element method(FEM), established the three-dimensional finite element calculation model of thermal elastic ,numerical
simulation the transient temperature field and stress field distribution of the single crystal silicon materials by the
pulsing laser irradiation, and analytic solution the temperature distribution and stress distribution of laser irradiation on
the silicon material , and analyzes the different parameters such as laser energy, pulse width, pulse number influence on
temperature and stress, and the intrinsic damage mechanism of pulsed laser irradiation on silicon were studied. The
results show that the silicon material is mainly in hot melt under the action of ablation damage.According to the
irradiation of different energy and different pulse laser ,we can obtain the center temperature distribution, then get the
law of the change of temperature with the variation of laser energy and pulse width in silicon material; according to the
principal stress and shear stress distribution in 110 direction with different energy and different pulse, we can get the
law of the change of stress distribution with the variation of laser energy and pulse width ;according to the principal
stress distribution of single pulse and pulse train in 110 direction, we can get the law of the change of stress with pulse
numbers in silicon.When power density of laser on optical material surface (or energy density) is the damage threshold,
the optical material surface will form a spontaneous, periodic, and permanent surface ripple, it is called periodic surface
structure laser induced (LIPSS).It is the condensed optical field of work to generate low dimensional quantum
structures by laser irradiation on Si samples. The pioneering work of research and development and application of low
dimensional quantum system has important academic value.The result of this paper provides theoretical foundation not
only for research of theories of Si and substrate thermal stress damage and its numerical simulation under laser
radiation but also for pulse laser technology and widening its application scope.
The unidirectional carbon fiber material is commonly used in the Carbon Fiber Reinforced Plastics (CFRP). The
COMSOL Multiphysics finite element analysis software was utilized in this paper. And the 3D anisotropy model, which
based on heat conduction equation, was established to simulate the temperature field of the carbon fiber irradiated by
pulse laser. The research focused on the influences of the laser width on the material temperature field.
The thermal analysis results indicated that during the process of irradiation, the temperature field distribution of the
carbon fiber was different from the distribution of laser spot on the surface. The incident laser is Gauss laser, but the
temperature field distribution presented oval. It resulted from the heat transfer coefficient of carbon fiber was different in
the axial and in the radial. The temperature passed along the fiber axial faster than the radial.
Under the condition of the laser energy density constant, and during the laser irradiation time, the depth of the carbon
fiber temperature field increased with the pulse width increasing, and the area of the carbon fiber temperature field
increased with the pulse width increasing, However, the temperature of the laser irradiated center showed a trend of
decrease with the increasing of pulse width. The results showed that when the laser affection was constant, the laser
energy affected on the carbon fiber per unit time was increased with the decrease of the pulse width. Due to the limits of
the heat transfer coefficient of the material and laser irradiation time, the energy was injected in carbon fiber within a
short time. With the reducing of the heat conduction area, the depth and the area of the temperature field would be also
decreased. With the increase of pulse width, the time of energy injected in carbon fiber was increased, and the laser
energy affected on the carbon fiber per unit time was decrease. With the heat conduction area increasing, the depth and
area of the temperature field would be also increased. In this paper, the rule of the temperature field changing with the
pulse width was consistent with the law of conservation of energy and the heat conduction.