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Through analysis and comparison of existing charging method works , adding more links constant current charging and constant voltage charging on the basis of the three-stage charging mode is proposed to receive more in line with rechargeable batteries five-phase characteristic curve charging mode. By scaling the control circuit and the PI regulator circuits use the charging current value and the constant voltage is sampled , a constant voltage corresponding to the error value to be compared and outputs the PWM control chip SG3525, causing the output current of the front end circuit chip , the regulation voltage , the error is gradually reduced until it reaches the steady-state output . 1 key components - integrated operational amplifier selection Integrated operational amplifier control circuit for the main components , essentially the entire op-amp circuits are designed to carry around , so choose the op amp circuit is particularly important . From the foregoing analysis, the current control and voltage control portion of each part requires three op amp ( both as an amplifier , a PI controller is used ) , the entire control circuit requires access to six integrated amplifier . Out of circuit integration considerations, decided to use a quad op amp manifold and a dual op amp with the completion of the manifold . By screening and the corresponding parameters available on the TI (TEXAS INSTRUMENTS TI ) website , and ultimately determine the use of quad op amp LF347 and dual op amp TLC2272.

the article introduces theelectric car charger control circuit design thinking and ideas, the controlcircuit to be able to with the front-end circuit switching power supply and MCUto cooperate to complete the following phases the constant current and constantvoltage charging battery automatic conversion, and stable in each phase of thecurrent value or the voltage value. Analyze the circuit module, includingsampling module, PWM signal module, proportional amplifier module, PIadjustment module.

To study the mechanical property of concrete column confined by GFRP, we conducted 6 groups of specimens under axial compress. The influences of GFRP wind mode and layers were taken into account. According to the results, bearing capacity and ductility of the spiral winding specimen was improved greatly. The bearing capacity of the 6° spiral winding concrete column’s improvement is 28%, more than it of 0°. The fiber polymer’s utilization ratio can be improved greatly when column were combined with all spiral wind. Strengthen the concrete column of ±15°cross spiral winding pretend to be stronger capacity of bearing axial press than it of 6° spiral winding, but limiting strain tends to be lower. Shearing crack often happens at the 45°of the specimen, so shearing failure can be prevented effectively by GFRP (45°).Effective deformation and strength can be provided by FRP at the direction of axial and circular, and the reinforcing steel bar in concrete column can be substituted partially.

More attention has been paid on the technology of BFRP in civil engineering due to it’s unique properties, such as high strength-to-weight radio, good resistance to corrosion and convenient to construction. In order to study the properties of BFRP sheets confined concrete column ,we did it through three groups of columns subjected to axial loading tests and FEM analyses, mainly considering the effect of spacing of straps of BFRP sheets confining concrete column.The results shows that the axial compressive strength and ductility of concrete column winded by BFRP straps have all increased and the process of destruction of concrete column wrapped by BFRP is longer than that of the unconfined concrete column.

The assessment method of fire-damaged concrete bridge with prestressed hollow core plate girders was presented in this paper. The historical sketch of assessment of fire-damaged concrete structures was briefly introduced. One fire-damaged concrete bridge with prestressed hollow core plate girders was shown as an example. The process of assessment of fire-damaged concrete bridge with prestressed hollow core plate girders was provided. According to the assessment results, methods of repair and strengthening were presented for different fire-damaged level of prestressed hollow core plate girders. The research results could help expand use of fire-damaged assessment and repair of prestressed concrete bridges.

In order to research the calculation method of shear capacity for fire-damaged reinforced concrete (RC) beams, the reason of drop of shear capacity was analyzed from material properties and transfer mechanisms of RC beams after fire. Formulas of shear capacity were suggested for fire-damaged RC beams. Based on test analysis, the values of reduction factors of shear capacity were proposed under concentrated load. The results show that suggested calculation method is capable of predicting shear capacity of fire-damaged RC beams exactly. The values of reduction factors of shear capacity need further experiments research.

The modality analysis of the reinforced concrete supported deep beams with opening is worked out by Finite Element Software ANSYS to obtain eight exponent natural vibration frequencies and modal charts. The result of three exponent natural vibration frequencies is agreement with the result of dynamic analysises. The preceding foundamental work is finished in order to do dynamic analysises and aseismic design of reinforced concrete deep beams with openings.

The technology of GFRP has received significant attentions in civil engineering due to their unique properties, such as high strength-to-weight radio, good resistance to corrosion and fatigue, convenient to construction and no additional dimension. Study the properties of GFRP confining concrete column through eight groups of columns subjected to axial loading, the effect of width of straps and spacing of straps of GFRP sheets confining concrete column is analyesed. The results are the axial compressive strength and ductility of concrete prism wrapped by GFRP sheets or GFRP straps have all increased to a certain degree, the process of destruction of concrete prism wrapped by GFRP become slower than common concrete prism.

The numerical simulation of reinforced concrete continuous deep beams with opening is analyzed by Finite Element Software ANSYS to establish reasonable mechanical model. The stress characteristics and deformation’s situation of the deep beams with opening are analyzed under concentrated load and different openings in different parts. The purpose is to supply some favorable suggestions in engineering application of reinforced concrete deep beam with openings.