Some problems about using link or zeroLength element

[YanYang]

Hello everyone,

I encountered some obstacles when using two-node or zero-length element as shown in the figure below. When I use only one element at the end of beam, the analysis is normal and can converge. But when I use two link elements continuously, the analysis is abnormal and the convergence fails. I tried the following solutions:

1) Two zero-length elements are connected by three nodes in the same position;

2) Two two-node link elements are connected by three nodes at different positions;

3) One zero-length element and one two-node link element;

The materials used for the link element are as follows:
First: 'HyperbolicGapMaterial' and 'Hysteretic' , are combined to form a material by 'Parallel';
Second: 'ImpactMaterial' and 'ElasticPP', are combined to form a material by 'Parallel';

My purpose is to monitor the force-deformation response of the two link elements separately. I would appreciate it if someone could help me solve this problem. Thanks.

[YanYang]

I guess the reason for the failure is that the relative deformation of the link element needs to be determined before the response can be calculated according to the predetermined force-deformation rule? If two link elements are connected in series, the relative deformation of the element becomes indeterminate, so the analysis is unstable and the convergence fails.

So what other simulation methods work well?