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仪器交易网 > 仪器知识 > 维修保养 > 金属材料旋转弯曲疲劳试验机 疲劳试验机如何做好保养

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金属材料旋转弯曲疲劳试验机 疲劳试验机如何做好保养

时间：2020-08-28    来源：仪多多仪器网    作者：仪多多商城     
　　该机根据《GB/T 4337-2008 金属材料 疲劳试验 旋转弯曲方法》设计制造，主要用于金属材料旋转弯曲疲劳的检测。被测试样安装在可调整空间的两夹头之间，试样弯曲规定角度后，左侧夹头夹紧试样左端并带动试样沿轴线旋转，右侧夹头约束长度位置和弯曲角度，试样右端夹头可在夹头座的套筒内自由旋转。通过调整或更换夹具，适应不同的被测试样的试验。试验机采用计算机控制操作，可设置弯曲角度、扭转速度。实时显示试验圈数、试验曲线、记录试验过程最大弯矩峰值，记录疲劳断裂的旋转次数，试样断裂自动停机，试验数据存储，打印试验结果。

　　10. 两夹头间直线. 两夹头间直线. 夹持试样直径范围：φ3～φ8（根据客户要求）

Hydraulic cylinder vibrates to a 400 Hz sine.

(DYNA-MESS Gmbh) and Hänchen reach new heights of performance

Modern quality standards mean that components are now facing more varied and useful tests than at any time before. DYNA-MESS Testing Systems specialises in testing machines for dynamic component and material testing. With its broad and varied range of standard and special test machines, the Aachen-based company exploits the possibilities of modern fluid technology to the best advantage. Its pièce de resistance is a special testing machine for elastomers which, with the help of standard hydraulic cylinders from Hänchen, realises controlled vibrations of 400 Hz in order, for instance, to test the damping of bearing elements made of rubber-metal composites for the automotive industry.

Hydraulics is cutting-edge technology

According to Dr. Marcus Jarchow, Managing Director of DYNA-MESS, "these test units are exposed to extreme stresses with a nominal force of 10 kN and a frequency of anything from 0 to 400 Hz. It has been extremely difficult to find a suitably high-performance hydraulic cylinder on the hydraulics market", because the test device depends on the perfect stick-slip behaviour of the hydraulic system. Cylinders with hydrostatically supported piston rod guides are normally used for this type of application, but the technical expenditure for this solution is enormous. "We have nevertheless kept our ears to the ground to try and find out who can offer some help with finding a solution" stated the Managing Director of DYNA-MESS. "Everybody hesitated when we mentioned the technical requirements, with the exception of Hänchen Hydraulik. A further argument in their favour was that they had their own test equipment and would be able to base their results on extensive experience. Ultimately, the hydraulic specialists from Ostfildern, near Stuttgart, offered a standard cylinder with patented, floating annular gap seal which is considerably more cost-effective than drives with hydrostatically supported piston rod guides". The PZL assembly series from Hänchen, however, also provides these high-end cylinders.

The PZR floating annular gap seal

The patented, floating annular gap seal from Hänchen permits the use of cost-effective PZR high-end test cylinders, in which a steel sleeve is positioned through a choke gap and thereby creates a contact-free sealing gap of just a few 1/100 mm. This process can, however, only function correctly with a production accuracy of only a few µm, as leaks would otherwise lead to an unacceptable loss of hydraulic fluid. This PZR assembly differs only by the slightly lesser absorption of the lateral forces from a cylinder with hydrostatically supported piston rod guide, but yields a considerable cost advantage. Thanks to their negligible friction, however, PZR cylinders offer maximum positioning and repeat accuracy and are stick-slip free, making them ideally suitable for extremely slow as well as fast movements and minimum travel over ranges of a very few µm. As lateral forces are not experienced in this 400 Hz DYNA-MESS test equipment, the decision was made in favour of these cylinders.

High-quality peripherals

The cylinder is equipped with a special inductive position measuring system and a force transducer with an extremely low natural frequency and yield measuring strips. Both sensors supply analog output signals which are digitalised with a resolution of 16 Bit and tested with more than 20 kHz. They supply the control with the necessary data, which must be converted practically in real time by a control card with its own high-performance processor. Tried-and-tested DYNA-MESS software modules were adapted to the special conditions to facilitate programming. A PC forms the basis for the Windows user interface. The valves represented yet another technical challenge, as they have to work with a control frequency of 16 kHz. The fluid circuit has been designed for 300 bar and operates at 40 l/min. This high power density enabled a low design size, because a high frequency with a wide frequency spectrum places extremely high demands on the mechanical construction: the frame must not have any natural resonance over the whole of the frequency range.

Commissioning

Commissioning proved to be a time-consuming exercise, particularly due to the need to tune in to the various frequency ranges. The frequency was increased in steps of 10, 20, 30 … up to 400 Hz, with the resonance having to be minimised at every stage. The complete control was also tuned during this time, in that the runtime delays between the reaction of the processor and its execution by the hydraulic system are captured and included in the control. Finally the control quality and curve form were optimised, this operation being followed by fine tuning with the help of a friction-free and loss-free spring, which measures the dynamic without phase displacement and so enables material tests to be carried out under clearly defined conditions. After up to 400 Hz had been reached, Dr. Jarchow’s team carried out further tests up to a frequency of 1,000 Hz. "We were surprised at what outputs were possible, up to double the nominal output at 800 Hz", said the hydraulic specialist. "It was only above this frequency that the limits of what is technically feasible at the moment were clearly reached. The hydraulic cylinder has more than matched the requirements placed on it, and that was with the use of a catalogue cylinder and at a very attractive price”. The finished system was then commissioned during the first quarter of 2002.

Practical application

Hänchen’s PZR hydraulic cylinders are now being used by a Daimler-Chrysler supplier to test vibration dampers for engine and gearbox suspensions for load carrying ability, damping behaviour and service life. These components are made from rubber-metal composite material with embedded passive hydraulic damping. The sealed glycol circuit in this component is used to dampen the vibrations. A new test bench enables the developers to optimise the damping characteristics. Sweep tests with a pre-selected load which corresponds to the engine or gearbox weight are used to determine at which frequency damping is most effective. For this test the frequency is superimposed over the static load with the aim of achieving an optimised damping over the whole frequency range of up to 400 Hz."

Our engineering competence, the experience and evaluation of our suppliers as well as the ability to develop test solutions together with our customers were the deciding factors", explained Dr. Jarchow, whose team performs all calculations, is responsible for design, software, electronic development, control, configuration as well as installation and realises the complete system in co-operation with the suppliers. "Suppliers whose products conform to our own high standards play a critical role. That is why we are working together with Hänchen Hydraulik". 疲劳试验机的特点都有哪些呢？

    疲劳试验机是一种主要用于测定金属及其合金材料在室温状态下的拉伸、压缩或拉、压交变负荷的疲劳性能试验的机器。

    关于疲劳试验机你们的了解有多少呢?

    下面来为大家详细介绍一下疲劳试验机的特点与使用时会出现的误差，一起来看看吧。

    疲劳试验机的特点与使用时会出现的误差

    疲劳试验机的特点

    首先，它是一种稳定性很不错的设备。

    类似于这种大型工业设备，用户对它的要求就是稳定性可靠，这不仅关系到正常的工作效率，同时也关系到每个工作人员的安全问题。

    可靠的稳定性主要体现在，设备不会因为阻力有所变化，就影响到运行，阻力有变化，设备也可以在范围之内正常工作。

    其次，低噪音。

    大型设备工作过程中难免会有很大的噪音，所以生产车间的环境往往会有大噪音，工作人员在这样的环境中工作对身体也没有好处。

    而该设备的噪音很低，赢得用户的认可。

    再其次，安装简单，维护方便。

    我们都知道大型设备安装的时候会比较麻烦，后期维护也会造成大的成本。

    但是疲劳试验机正好相反，简单的结构和精湛的工艺技术，减少了安装的繁琐，后期维护也简单方便；

    据了解，设备运行过程中不需要使用水源，电也用的好，所以这也大大减少成本支出。

    另外，使用寿命长久。

    疲劳试验机的价格昂贵，能够购买一台这样的设备，对于任何一个厂子都是一笔不小的开支。

    幸好设备使用寿命长久，能够为厂子带来更大的经济效益。

    还有，疲劳试验机是一种高科技设备，品质优越，效率高，成本低，这样的设备不断在哪里都是用户青睐的。

标签: 疲劳试验机 疲劳试验机标签： 疲劳试验机的特点都有哪些呢？_疲劳试验机组合标题：

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